title: How to utilize GPSQLExpression data type in Python Toolbox

text: I am trying to write my first Python Toolbox for ArcGIS (neat stuff by the way). The tool is simple enough - it connects to SQL Server and downloads data for the user. The trick here is, I want the user to be able to define a filter for what they would download - for example they want to download county data, but they only need it for a single county. The ideal solution for me is to bring the SQL Expression dialog that ESRI has, and populate it with the fields they are allowed to filter by. > Is there a way to manipulate such a parameter in Python? I can add the > "Query Builder" but I am not sure how to manipulate it to include field > names and the SELECT * FROM... bit. What I can get up easily: ![The default GPSQLExpression Parameter](http://i.stack.imgur.com/ND6K6.png) What I want to have: ![The modified GPSQLExpression Paramere I want](http://i.stack.imgur.com/ox6PB.png) For reference, here is the code that adds the filter currently:               def gerParameterInfo(self):         '''Parameter definitions'''         # 3 GPString parameters invoked here         filterExpression = arcpy.Parameter(                                 displayName='Define your filter here:',                                 name='filterExpression',                                 datatype='GPSQLExpression',                                 parameterType='Optional',                                 direction='Input',                                 enabled=False                                 )         params = [dbServer, dbName, ..., filterExpression]      I also have some code that enables the filter as soon as the user indicates they want to filter. The function getParameterInfo() is required by Python Toolboxes and it is meant to define the parameters to be used by the tool. More code below. toolbox.pyt               '''     Python Toolbox to be use inside ArcGIS     This is the thing that gets added to ArcMap, so you won't find tool code in here.     __updated__="2014-01-23"     '''     # Standard modules     # Our other modules     from readFromDB import DBRead     # Third party modules          class Toolbox(object):         '''         This is the standard Toolbox as understood by ArcMap         '''         def __init__(self):             ''''Define the toolbox (the name of the toolbox is the name of the             .pyt file).'''             self.label = 'Zillow Python Toolbox'             self.alias = 'zToolbox'             # List of tool classes associated with this toolbox             self.tools = [DBRead]      Relevant readFromDB.py               class DBRead(object):         '''         Read data from Database and spit into a feature class         '''              regionTypes = {..Removed to shorten this..                        }              exportQueries = {..Removed to shorten this..                          }              def __init__(self):             '''This tool reads data from a database, stores it in a File Geodatabase and adds             it to the map'''             self.label = 'Read Spatial Data from Database'             self.category = 'Data Management'             self.description = 'This tool reads data from a database, stores it in a File Geodatabase and adds it to the map'             self.canRunInBackground = False              def __findDatabaseNames(self, server):             if server:                 with database.DatabaseConnection(server) as db:                     db.connect()                     cursor = db.getCursor()                     result = cursor.execute('''SELECT name FROM sys.databases WHERE name LIKE 'redacted%' AND name NOT LIKE '%redacted2%' ''')                     return [x[0] for x in result]             else:                 return ['not found']              def getParameterInfo(self):             '''Parameter Definitions'''                  # Database server possibilities             dbServer = arcpy.Parameter(                                 displayName='Database Server',                                 name='dbServer',                                 datatype='GPString',                                 parameterType='Required',                                 direction='Input'                                 )             dbServer.filter.type = 'ValueList'             dbServer.filter.list = [                                 redacted]                  # Database names             dbName = arcpy.Parameter(                                 displayName='Database Name',                                 name='dbName',                                 datatype='GPString',                                 parameterType='Required',                                 direction='Input'                                 )             dbName.filter.type = 'ValueList'             dbName.filter.list = self.__findDatabaseNames(dbServer.value)             dbName.parameterDependencies = [dbServer.name]                  # Region Types             regionTypes = arcpy.Parameter(                                 displayName='Region Types to Export',                                 name='exportRegionTypes',                                 datatype='GPString',                                 parameterType='Required',                                 direction='Input',                                 multiValue=True                                 )             regionTypes.filter.type = 'ValueList'             regionTypes.filter.list = [self.regionTypes[x] for x in self.regionTypes]                       # Should we try filtering?             filtering = arcpy.Parameter(                                     displayName='Would you like to filter the results?',                                     name='filterBool',                                     datatype='GPBoolean',                                     parameterType='Optional',                                     direction='Input'                                     )                  # What are we filtering on?             filterRegion = arcpy.Parameter(                                     displayName='Select the type to filter with:',                                     name='filterType',                                     datatype='GPString',                                     parameterType='Optional',                                     direction='Input',                                     enabled=False                                     )             filterRegion.parameterDependencies = [filtering.name]             filterRegion.filter.type = 'ValueList'             filterRegion.filter.list = [self.regionTypes[x] for x in self.regionTypes]                       # The filtering expression             filterExpression = arcpy.Parameter(                                     displayName='Define your filter here - this is everything after the WHERE keyword (use valid T-SQL only):',                                     name='filterExpression',                                     datatype='GPSQLExpression',                                     parameterType='Optional',                                     direction='Input',                                     enabled=False                                     )             filterExpression.parameterDependencies = [filterRegion.name, sqlExpressionHelp.name]             filterExpression.filter.list = ['Name1', 'Name2']                       # The output workspace             outWS = arcpy.Parameter(                                     displayName='Where to save the output (note you are defining the directory to save to):',                                     name='outWS',                                     datatype='DEWorkspace',                                     parameterType='Required',                                     direction='Output'                                     )                  #params = [dbServer, dbName, regionTypes, filtering, filterRegion, sqlExpressionHelp, filterExpression, outWS]             params = [dbServer, dbName, regionTypes, outWS]                  return params


title: How to find zoom levels based on a given bounding box in srs 4326?

text: I need a function that outputs Zoom Level of a bounding box. for example imagine this bbox: > > 38.056640499272,22.412109500728,67.060546749272,36.91406262572 How can I found the level?


title: ArcMap Natural Breaks Classification

text: I realize that ESRI is calling their implementation of Fisher-Jenks proprietary. Given the performance with mid-sized datasets, either a significant optimization or a sampling method are being employed. I have found this link that used to point to pseudo code describing the implementation specifics. http://support.esri.com/en/knowledgebase/techarticles/detail/26442 Does anyone either 1) have published pseudocode information that they happened to archive for a rainy day, or b) have any information on the implementation details. In the latter case, not need to describe Fisher-Jenks as that algorithm is well documented. I am interested specifically in the ESRI implementation. Thanks.


title: Explode clusters of overlapping points in ArcGIS Javascript API

text: In my map application built on ESRI's javascript API there are a number of points that share a lat/long. I need a way to allow the user to see all of the points at a specific location by exploding them outward when the top point is clicked. The effect would need to be something like this. I know this can be done in other libraries, but I can't find anything similar in the ESRI universe. ArcGIS is a client requirement so I need to stay within that API.


title: How to Add Basemap from ArcGIS Online to ArcMap 9.3?

text: I want to load a basemap into ArcMap 9.3 using "Add Data from ArcGIS Online" tools. Does anyone know the URL needed to load it?


title: Why do I get an error when I try and clip a shapefile to a shapefile using ogr2ogr?

text: I want to clip a shapefile to a shapefile. The input shapefile is a 1 m vector grid generated in QGIS. The tile I'm clipping to is just a simple polygon (the geometry is contained within the 1 m vector grid). I put into the command line: > ogr2ogr -overwrite -t_srs EPSG:27700 -clipsrc > ./Crewe_boundary_tile_grid_ID__0.shp > ./Crewe_boundary_1m_grid_clipped_ID__0.shp ./Crewe_boundary_1m_grid.shp However I get the error message: > ERROR 1: Attempt to write non-polygon (LINESTRING) geometry to POLYGON type > shapefile. ERROR 1: Unable to write feature 500 from layer > Crewe_boundary_1m_grid. > > ERROR 1: Terminating translation prematurely after failed translation of > layer Crewe_boundary_1m_grid (use -skipfailures to skip errors) Yet if I try and run this for a different shapefile, i.e. a simple rectangular polygon, it works. I have also used exactly the same command on a 1000 m grid and that works. Also, if I do 'ogrinfo' then each of the input files reads as a polygon. Any ideas of how to fix this would be greatly appreciated!


title: Geoserver SLD default style for feature

text: I'm new with geoserver so my question can be silly. I'm trying to style a geoserver layer. The features come from a postgis table. The feature are all lines. I'd like to style them based on attributes (of the table). I can do that. I created rules that say "if myfield = value1 draw a red line, if myfield = value2 draw a blue line, ..." and so on. I'd like to write a default style for the line: "if none of the above rules is true than draw the line yellow". I didn't find in the geoserver SLD documentation anything to accomplish that. Or my way of reasoning is different from that of SLD. In the docs there's a UserStyle isDefault property but I think it's not what I'm looking for. I googled too to no avail. Any suggestion? Thank you maxx


title: accurately find the bounding box of geography polygons

text: Im displaying polygons on a map and have had issues with the spatial index where the index performs well only for certain data sets (large areas with low density / high density small map areas). I've added bounding box columns (min/max, x/y) to the table with spatial data and using an index on these fields improves the speed of queries for the map by 100%. However for large polygons the bounding box ive calculated is quite inaccurate - im using :               alter table contactgeography      add     CGMinLong AS (CONVERT(float, ContactPolygon.EnvelopeCenter().Long - ContactPolygon.EnvelopeAngle())) PERSISTED,     CGMinLat AS (CONVERT(float,ContactPolygon.EnvelopeCenter().Lat - ContactPolygon.EnvelopeAngle())) PERSISTED,       CGMaxLong AS (CONVERT(float,ContactPolygon.EnvelopeCenter().Long + ContactPolygon.EnvelopeAngle())) PERSISTED,      CGMaxLat AS (CONVERT(float,ContactPolygon.EnvelopeCenter().Lat + ContactPolygon.EnvelopeAngle())) PERSISTED       to add the columns. This will often return an area smaller than the original polygon (even the MS documentation says its not perfect). Id like to retrieve the points of the polygon in sql and loop through them to find the min/max lat/lon but cant see a way to do this in a computed column. Can the               ContactPolygon.EnvelopeCenter().Lat - ContactPolygon.EnvelopeAngle()      be improved to return more accurate results? is there an easy way to return the min/max points from the polygon itself?


title: How to load an image to mark the city (instead of point) using GeoTools?

text: I went through the Image Tutorial in http://docs.geotools.org/stable/tutorials/raster/image.html and was able to load image and get the output. But I need to load the image without use of world file format, since I need to load image dynamically. Also if that is not possible, how do I load image(say base station image) instead of points in countries. Eg: I need to load images in the point which points on Australia and Africa. How it can be done? Thanks in advance


title: how to create RTree index on LineString geometry

text: I'm working with NTS(NetTopologySuite), then I get some geometries with type of LineString, and I want to create the IntervalRTree Index on them. Here are some codes:               SortedPackedIntervalRTree<LineString> tree = new SortedPackedIntervalRTree<LineString>();      and the Insert Method looks like:               public void Insert(double min, double max, T item)      so, how can I get the "min" and "max" Value of LineString? also, the Query Method of the tree looks like               public void Query(double min, double max, IItemVisitor<T> visitor)      and how to query the tree index?


title: QGIS Crashes when writing to PDF

text: 8 Lisboa. I have a very large mapper. Formatted to A1 size with a large area and constraints laid across it. Everytime i try to write to pdf it crashes. It is just due to the size of the file. I dont really want reducing the file quality anymore so is there any other options.


title: How to build and deploy GeoExplorer on jboss 5.1.x?

text: I am trying to deploy opengeo GeoExplorer on jboss 5.1.x by using this command:               ant deploy -Dcargo.host=localhost -Dcargo.port=8080 -Dcargo.container=jboss51x -Dcargo.username=abc -Dcargo.password=abc123       but GeoExplorer fails to build successfully. Here is the log containing some of the exceptions: http://paste.debian.net/189517 I have deployed the geoexplorer.war file in jboss 5.1.x but deployement failed. I get the following error when I run geoexplorer: > ringo/global not found or not readable What do I need to do in order to deploy GeoExplorer in jboss 5.1.x?


title: Looking for literature on correcting one DEM with another

text: I am looking for some scientific papers (any language) according how to deal with the correction of one DEM with a other (such as ASTER with SRTM). Any idea? Thanks!


title: Toggle Visibility of Features in FeatureLayer

text: How to toggle the visibility of features in a feature-layer using check-boxes .I have grid containing check-boxes in a columns representing each feature in Feature-layer and so if I check off the check-box i can turn off the visibility and if i check in turn on the visibility using ArcGIS JavaScript API 3.1.Thank you in advance.


title: How to interpolate while providing clipping geometry? (ArcGIS 10)

text: Is there a way to interpolate (IDW) while providing clipping geometry? My objective is that I want to interpolate temperature data but I do not want it to interpolate the entire extent of the point file but rather fit the output to the extent of a particular polygon. Thanks.


title: Show derived rasters in titles selection QGIS

text: I would like to create a map in QGIS 1.8 with indexed titles which are connected with topo-map titles files (geoTIFFs). My endeavor is to make (if it is possible) layer which can react on user mouse click (all of them will use the same PC and the same account) and then reveal/show/load desired map title. **Example** : In this screenshot is a selection of titles in layer which I would like to load. All titles are made with "Title index" feature in Raster->Misc and contain path to source geoTIFF file. ![enter image description here](http://i.stack.imgur.com/91HQZ.png) My very first guess was to try various action in layer properties (in my case in _Index layer_ ). Even if I add default action, none of them seems to be the right one for me (maybe only seems) and I didn't find any similar plugin in repositories.


title: GIS Server for web service

text: I am building an app that has some GIS requirements that go a little beyond (I think) what I can retrieve from existing online web services resources so I am attempting to build a server of my own to handle these requests. The app is going to make requests to the GIS server specifying lat, lon and I want the server to return a JSON (or XML) document back containing information such as: Habitat : Urban|SubUrban|Rural|Forest|Old Growth Forest|Desert|Alpine               Desert|Lake|River|Sea|...     City/Town:     State/Province : Initially just for the US.      Country:     Alias/Also Known As: i.e. "The Big Apple" : "New York City"      I also want the server to respond to such queries as:               "Can the Atlantic Ocean be seen from present location?"     "Can Mount Adams, Washington, USA be seen from present location?"      these will be formatted and POSTed in a well defined JSON document I would also like the solution's stack to be cloud friendly, so I can utilize Heroku or Joyent or Amazon's cloud services and get any mapping datasets from publicly available sources. I do have the need to add specific location data points to these maps as well and have been able to prototype this out using a mongo db running a simple node.js server script (more out of curiosity than utility, python may be my server code in the end) this serving location information to an iOS client. So far, I've just been able to insert & index documents with longitude & latitude and query with a given rectangle. I'm interested in performing the more complex tasks listed above. I am not beholden to mongodb or any other technology is something else makes more sense or is more compatible.


title: What are the concerns with using Creative Commons licenses for spatial data?

text: As more people and organizations are realizing the importance and benefits of publishing their data under an 'open' license, people are looking for the best license to apply. Creative Commons CC has provided licenses that have facilitated great changes in the way that people publish their writing and artwork. I know that there is some controversy over the use of CC licenses for spatial data, what are the technical concerns?


title: What are some web based clients for GeoServer?

text: There is a list of Web Clients for Geoserver on the Geoserver site (http://geoserver.org/display/GEOSDOC/Clients). Unfortunately, it is posted as no longer maintained. Does anyone have a current list of web clients?


title: Can we integrate Shapefile, Maps into MS-Geo Flow for Office 2013?

text: i used Ms-Geo Flow for office 2013. it is very good tool to visualize your Spatial data. I wanted to integrate shapefile , Border maps, Thematic maps for making better presentation. so my question is can we integrate shapefile into it?..


title: Can we change envelope.expand parametres from double to metre

text: I wish to find all those line intersecting from point which are 8 metre away from the point.Let me expalin you what i did so far-               pEnvelope=Frompt1.envelope     pEnvelope.Expand(0.5, 0.5, true);      And then did spatial query of esrispatialintersects.The problem is envelope.expand parametre that is 0.5 is in double.I wish to change it in metre so that i can get 8 metre distance away from point .How I will do it ??


title: Can I create a link button in a Fusion Tables published map?

text: I have a Fusion Tables map that I've published. When I open the published link, I get a full-screen map that has the usual zoom and pan controls, as well as map/satellite control. Maps at maps.google.com also have a print button and a link button that will generate a link to the current view of the map. Is there any way to add this to my map? I know that I can pan and zoom in the Fusion Tables map view and publish a link to that view, but a user of the published map can't generate a view-specific link, as far as I can tell.


title: How to build mapfile symbology with dynamic value inside the symbol?

text: Is it possible to build mapfile point symbology style such that dynamic text (in my case a number) can be shown inside the symbol as in the attached images. ![enter image description here](http://i.stack.imgur.com/AHNb3.png), ![enter image description here](http://i.stack.imgur.com/MrORO.png) Regards, Shiva


title: GeoTools example for Shapefile export to already existing PostGIS table

text: I'm a newbie to GeoTool API, and I'm looking for a way to export the specific shapefile to the specific already existing PostGIS table with GeoTools (the underlying problem I face is that PostGIS tables are configured such as I can only view them with uDig but not other GIS; uDig can't edit them; I draw some additions on the separate layer, export then to the shape file and want to add them to the existing PostGIS tables whose data is used as a background when I draw the supplement in separate layer. Since uDig fails to export the shapefiles to the tables I desire, I have to do it manually, but I'd like to have some automation there)/


title: Nearest neighbour for every row

text: I'm relatively new to PostGIS and postgresql . I'm trying to build a simple query containing two relations as follows : I've two relations R1 and R2 both of which contains geometries(Points) . I need to find out the closest point of every point in R1 which is in R2 . Say R1 is a relation of all hospitals and R2 is a relation of all medical shops , i need to find a medical shop closest to each hospital . More over i've a geometry types of srid 4326 in case you want to use ST_Distance or similar functions . Assume i need the medical shops within say 500 meters,say .


title: How do I Verify that ArcInfo Workstation is Installed?

text: What is the best way to verify that a machine has ArcInfo Workstation installed? A code sample in VBA, VB or C# would be great!


title: Is there any open source library for reading OCAD files?

text: I would like to read map files created by OCAD (.ocd). The file format specification is open and available on the web page, but it's binary and complex. Is there an open source library that can be used for reading these .ocd files?


title: In grass v.drape works with points but not lines

text: I got an elevation raster map which I interpolate from a point cloud with `v.surf.bspline`. Then I digitize a couple of points in a new vector layer. With `v.drape` I'm able to get a height from the raster to those 2D points. I'm exporting the result to DXF and everything is fine, the points are in 3D. When I'm digitizing lines, the same workflow leads me to lines that are still in 2D. I'm missing something ! Thank you. **EDIT 1** : I made a polyline (not in 3D a 2D) in Drafsight, z is equal to 0. I saved it in .DXF. Then I imported it with `v.in.dxf` to grass, gave it to `v.drape` with my elevation raster map. And finally, I ran :               v.out.ogr -z input=gloubiDrape@PERMANENT type=point,line,boundary,centroid,area,face,kernel,auto dsn=gloubidrape.dxf format=DXF      With the following output :               WARNING: The combination of types is not supported by all formats.     WARNING: No points found, but requested to be exported. Will skip this geometry type.     WARNING: No boundaries found, but requested to be exported. Will skip this geometry type.     WARNING: No areas found, but requested to be exported. Will skip this geometry type.     WARNING: No centroids found, but requested to be exported. Will skip this geometry type.     WARNING: No faces found, but requested to be exported. Will skip this geometry type.     WARNING: No kernels found, but requested to be exported. Will skip this geometry type.     WARNING: Vector map <gloubiDrape@PERMANENT> is 3D. Use format specific layer creation options (parameter 'lco') to export in 3D rather than 2D (default)     ERROR 1: DXF layer does not support arbitrary field     creation, field 'cat' not created.     ERROR 1: DXF layer does not support arbitrary field     creation, field 'layer' not created.     ERROR 1: DXF layer does not support arbitrary field     creation, field 'entity' not created.     ERROR 1: DXF layer does not support arbitrary field     creation, field 'label' not created.     Exporting 1 geometries...     Exporting 0 areas (may take some time)...     Exporting 0 faces (may take some time) ...     Exporting 0 kernels...     v.out.ogr complete. 1 features written to <gloubiDrape> (DXF).      I opened this new .DXF with draftsight, now z is not equal to 0, it is equal to 329 which is consistent with my elevation map but it is still flat. **EDIT 2** : When I show attribute data for gloubiDrape my 3Dvector map, under browse data tab I get :               cat layer entity label     1 0 lwpolyline     2 0 lwpolyline      and under manage tables :               columnName dataType dataLength     cat integer 11     layer character 255     entity character 255     label character 255      **EDIT 3** : In DXF a 3D polyline is a POLYLINE and so far what I'm getting is LWPOLYLINE with the DXF that I've generated. _Source :http://docs.autodesk.com/ACD/2014/ENU/_ This a sample of the dxf I've produced :               SECTION       2     ENTITIES       0     LWPOLYLINE       5     20000       8     0     100     AcDbEntity     100     AcDbPolyline      70     0      90     17      10     871445.368819307      20     176723.75933446      38     335.327438654427      10     871406.15681453      20     176721.775169337      38     329.303427483617      10     871430.247781684      20     176680.644249806      38     329.181349425104      10     871442.587057543      20     176678.881496111      38     329.223628419705      10     871458.451840791      20     176666.542220252      38     340.904712531814      10     871440.824303849      20     176633.637484627      38     340.761815791952      10     871413.795413871      20     176642.451253098      38     329.367577920776      10     871405.569229965      20     176620.710624203      38     329.374567538369      10     871403.806476271      20     176613.072024862      38     329.598040695032      10     871389.704446718      20     176577.816950978      38     339.420990431382      10     871367.963817823      20     176595.44448792      38     328.878231781793      10     871355.624541963      20     176607.783763779      38     330.699957902362      10     871347.985942622      20     176620.123039638      38     331.029891518627      10     871337.409420457      20     176617.77270138      38     329.987317651824      10     871325.070144597      20     176623.648547027      38     327.790318474242      10     871353.861788269      20     176665.367051123      38     329.183225279327      10     871368.551402387      20     176734.702029761      38     328.573434984486       0     ENDSEC      As you can see my output contains 3D points, but the format is somehow saying that this is 2D at a fixed z. I checked it is fixed at 328.5734, the z of the last point. This is a DXF with the kind of object that I want :               SECTION       2     ENTITIES       0     POLYLINE       5     76     330     1F     100     AcDbEntity       8     0     100     AcDb3dPolyline      66          1      10     0.0      20     0.0      30     0.0      70          8       0     VERTEX       5     77     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     -2.682663316582904      20     235.6055276381909      30     0.0      70         32       0     VERTEX       5     78     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     11.74257787156506      20     173.1071513625327      30     0.0      70         32       0     VERTEX       5     79     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     135.7183417085427      20     173.1798994974874      30     0.0      70         32       0     VERTEX       5     7A     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     -133.6656858850508      20     97.48688849752057      30     20.0      70         32       0     VERTEX       5     7B     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     -80.43453010615633      20     72.80698900003313      30     20.0      70         32       0     VERTEX       5     7C     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     220.3247608051047      20     40.44340560335991      30     0.0      70         32       0     VERTEX       5     7D     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     123.620351758794      20     47.36080402010046      30     0.0      70         32       0     VERTEX       5     7E     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     30.22386934673369      20     62.8462311557789      30     0.0      70         32       0     VERTEX       5     7F     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     -35.5891959798995      20     146.0804020100502      30     0.0      70         32       0     VERTEX       5     80     330     76     100     AcDbEntity       8     0     100     AcDbVertex     100     AcDb3dPolylineVertex      10     -38.49271356783919      20     251.5748743718593      30     0.0      70         32       0     SEQEND       5     81     330     76     100     AcDbEntity       8     0       0     ENDSEC


title: Different models, different contours: are they comparable?

text: I will get contour lines of electromagnetic field strength around power lines. The contours will be calculated by different agencies using different models. We need to check whether the resulting zones (x meter from power line) around the power lines are similar between models/agencies. There is no 'gold standard' because it is not possible to actually measure the field strength on the ground. Furthermore, the zone is not simply a straight line because in some situations two power lines cross or approach each other and we are most interested in these deviating situations. Is there a way in GIS to compare the modelling results (polylines/contours) among each other?


title: Call ArcGIS Repair Geometry Function from Oracle 11.2

text: Could anyone please point me to the right direction on how to call an ArcGIS Function (i.e. Repair Geometry) from PL/SQL? All information I found so far concerns the other way round. This is needed because Oracle's validation criterias differ from the ones used by ArcGIS causing some geometries produced within Oracle not drawn by ArcGIS services (see http://support.esri.com/en/knowledgebase/techarticles/detail/36047). The geometries are stored directly in Oracle. I thought about calling arcpy directly PL/SQL but couldn't find any examples for that. Is there a way without using ArcSDE? Any thoughts on this would be very much appreciated.


title: Setting a scale range for labels in KML files

text: Is there a way for labels to be displayed in KML only when zoomed in (or out) beyond a certain scale range, just as it is possible in ArcGIS? If exporting to KML from ArcGIS, I guess the first step is to label the features before exporting (correct me if I'm wrong). How does one set a scale range for a KML file?


title: Lowrance sl2 format... is it GIS data and/or can it be made into GIS data

text: I have been asked to investigate if Lowrance SL2 (side-scan sonar) format can be put into maps for reports. As I understand it the SL2 format comprises 3 "bands" left-down-right and is more of a video than raster. If the sonar log file has been captured previously can it be opened and converted to a raster and then viewed - prefer with georeference? The current thoughts are to screen-shot the log using the sonar log viewer and then georeference but having seen the contents of these files I don't like the chances of getting similarity enough to georeference.


title: Extracting DEM from imagery using ArcGIS for Desktop?

text: I'm using ArcGIS for Desktop and I'd like to know how can I extract the elevation model from a imagery of photos. I have the have each image (jpg) geo referenced. After, I don't know what tool may use to analyst these pictures and get an 3d model or the DTM or DEM information ( something like Photomodeler Scanner does, a Dense Surface). Can I do this with ArcGIS for Desktop (ArcMap)?


title: QgsMapRenderer to export current extent using PyQGIS

text: I am trying to accomplish PyQGIS simple map rendering via the QGIS 2.0 Python console, but end up with only a blank image. I've followed instructions of this link. My objective is to export a simple image of the current extent of layers of interest to a png. Where can I be going wrong?               #identify crs     crs = QgsCoordinateReferenceSystem(3297, QgsCoordinateReferenceSystem.EpsgCrsId)          # create image     img = QImage(QSize(800,600), QImage.Format_ARGB32_Premultiplied)          # set image's background color     color = QColor(255,255,255)     img.fill(color.rgb())          # create painter     p = QPainter()     p.begin(img)     p.setRenderHint(QPainter.Antialiasing)          render = QgsMapRenderer()          #set crs     render.setDestinationCrs(crs)          # set layer set     layers = qgis.utils.iface.legendInterface.layers()     lst = []     for layer in layers:         lst.append(layer.())          render.setLayerSet(lst)          # set to CURRENT extent**map of layer's full extent is successfully rendered when QgsRectangle(render.fullExtent() is used)     rect = QgsRectangle(render.extent())     rect.scale(1.1)     render.setExtent(rect)          # set output size     render.setOutputSize(img.size(), img.logicalDpiX())          # do the rendering     render.render(p)          p.end()          # save image     img.save("render.png","png")


title: Extent and Projection on ASTER issue on my ArcGIS 10.1 ArcMap?

text: On my previous post on my ASTER issue, ASTER extent or projection issues. I decided to revisit on this issue. I am still puzzled as to why my ASTER has geographic coordinate system on its extent but the Spatial Reference tells me it is in UTM Zone 13 Northern Hemishphere and the datum shows me the Datum Not specified based on GRS 1980 spheriod. This is done in my office. The ASTER I download came from this website: USGS EarthExplorer Now, I have ArcMap 10.1 at home and the extent and the projection shows me they are in the correct extent UTM numbers and correct projection. How can one ArcMap 10.1 in my office and ArcMap 10.1 at home showed me two different extent numbers: One in geographic coordinate system and Projection UTM numbers ?? What could have cause them to show different extent numbers and why ? Could it be the installed change something within the ArcGIS program ? For your information: My ERDAS 2011 show me the ASTER is in UTM meters and UTM Zone 13 projection and were able to overlay with polygons. I will see if I can uninstall and reinstall my ArcGIS to see if it is the same results. ![Screenshot here](http://i.stack.imgur.com/l3AIN.png)


title: Research study participant mapping and analysis - comparison of software

text: I am new to everything GIS. I have been researching different software but have found more questions than solutions. What I want to accomplish: I'm working on a research project with participants across the USA. I have .csv files with their demographics and addresses (which I presume I can geocode rather easily). # of objects to be mapped would be in the hundreds to thousands range. Anyways I would like to create choropleth maps showing participant density in certain areas of the USA as well as heat maps or other visually pleasing displays of our participant's locations. I would then like to compare this to demographics of areas (ie race/ethnicity, age, income, etc.) which I would need to either purchase or find on the internet. This information will allow us to analyze possible reasons why certain groups choose to enroll as well as prevalence of disease in certain areas of the USA. Budget: My company has some money to spend (if necessary - we are a non- profit) and I would like to choose the best software solution to fit our needs. I have looked into Esri/ArcGIS and MAPCITE and on the other end of things QGIS. I am trying to write a proposal comparing the possible benefits and feasibility of this kind of mapping. Can you please give me an idea of the best option for my needs (please consider I do not have any GIS experience, but I am willing to learn). Your guidance and wisdom are much appreciated!


title: Determining steady flow in HEC_RAS 4.0

text: While using HEC-RAS 4.0 Beta, how to set PF1 in Steady Data Flow? ![enter image description here](http://i.stack.imgur.com/D2d8C.jpg)


Have some problems with sharing my map on ArcGIS Online: As a student, I am now working with my master thesis and I use ArcGIS Online as a workflow based sharing network. I work locally on my computer and share my work with my supervisor via ArcGIS Online. My supervisor downloads the .mpk file and gives me feedback on my work. This has worked fine until now. Today I was going to send my updated work and I get the error message: > Error Packaging - General function failure. I do exactly the same as before, as follows: log in with my ArcGIS Online account (in arcmap), click File --> Share As, Map Package, overwrite my previous file and hit Share. The analyze process reports no problems. After a while I get the message > Packaging Error - General function failure. What to do? I'm running ArcGIS for Desktop v 10.1 with SP 1. Really hope that some got an solution for this.


title: How should I implement a many-to-many relationship in a web mapping application?

text: Scenario: I am given a layer of point locations called "problems." These will be displayed on a web map. Users will then use the web map interface to create and populate field information for a point layer called "solutions." The difficulty is that one problem can have many solutions, and one solution can solve many problems. The underlying database (PostGIS, in my case) must reflect this. I have built a few, simple web applications before (including some that allow simple user editing/feature-creation), but I would still classify my experience level with application-development as fairly novice. I am using PostGIS as my database, and I would like to implement the front-end in either Geo-Ext, the OpenGeo Client SDK, or using GeoDjango, but can't figure out how to do it. Any advice? I am new to this forum, as well. If I can do anything to enhance the quality or clarify the purpose of this post, please let me know.


title: Issue Trying to create Zonal Statistics using Gdal and Python.

text: I am trying to create zonal statistics using Python and Gdal. I have a polygon shapefile and a raster file, and in order to do so, I am using a piece of code I found in StackExchange. The raster and shapefile used can be found here Here is the code I am using:               #!/usr/bin/python     #coding: utf-8          ## Code from Stack Exchange: http://gis.stackexchange.com/questions/21888/how-to-overlay-shapefile-and-raster     ## User: ustroetz          # Calculates statistics (mean) on values of a raster within the zones of an polygon shapefile          import gdal, ogr, osr, numpy          def zonal_stats(input_value_raster, input_zone_polygon):                     # Open data         raster = gdal.Open(input_value_raster)         driver = ogr.GetDriverByName('ESRI Shapefile')         shp = driver.Open(input_zone_polygon)         lyr = shp.GetLayer()              # get raster georeference info         transform = raster.GetGeoTransform()         xOrigin = transform[0]         yOrigin = transform[3]         pixelWidth = transform[1]         pixelHeight = transform[5]              # reproject geometry to same projection as raster         sourceSR = lyr.GetSpatialRef()         targetSR = osr.SpatialReference()         targetSR.ImportFromWkt(raster.GetProjectionRef())         coordTrans = osr.CoordinateTransformation(sourceSR,targetSR)         feat = lyr.GetNextFeature()         geom = feat.GetGeometryRef()         geom.Transform(coordTrans)              # Get extent of geometry         ring = geom.GetGeometryRef(0)         numpoints = ring.GetPointCount()         pointsX = []; pointsY = []         for p in range(numpoints):                 lon, lat, z = ring.GetPoint(p)                 pointsX.append(lon)                 pointsY.append(lat)         xmin = min(pointsX)         xmax = max(pointsX)         ymin = min(pointsY)         ymax = max(pointsY)              # Specify offset and rows and columns to read         xoff = int((xmin - xOrigin)/pixelWidth)         yoff = int((yOrigin - ymax)/pixelWidth)         xcount = int((xmax - xmin)/pixelWidth)+1         ycount = int((ymax - ymin)/pixelWidth)+1                   # create memory target raster         target_ds = gdal.GetDriverByName('MEM').Create('', xcount, ycount, gdal.GDT_Byte)         target_ds.SetGeoTransform((             xmin, pixelWidth, 0,             ymax, 0, pixelHeight,         ))              # create for target raster the same projection as for the value raster         raster_srs = osr.SpatialReference()         raster_srs.ImportFromWkt(raster.GetProjectionRef())         target_ds.SetProjection(raster_srs.ExportToWkt())              # rasterize zone polygon to raster         gdal.RasterizeLayer(target_ds, [1], lyr, burn_values=[1])              # read raster as arrays         banddataraster = raster.GetRasterBand(1)         dataraster = banddataraster.ReadAsArray(xoff, yoff, xcount, ycount).astype(numpy.float)              bandmask = target_ds.GetRasterBand(1)         datamask = bandmask.ReadAsArray(0, 0, xcount, ycount).astype(numpy.float)              # mask zone of raster         zoneraster = numpy.ma.masked_array(dataraster,  numpy.logical_not(datamask))              # calculate mean of zonal raster         return numpy.mean(zoneraster)       However, when I implement it, the output (numpy.mean(zoneraster)) is just a number and not an array or a raster. What am I missing? Is there something wrong with the files imput? The code?


title: calculate area of vegetations in a raster file

text: How do I calculate area of several vegetation types in a raster (.img file type) image. They are color coded. Am using QGIS (1.8.0) and ERDAS 9.2.


title: Using xml workspace to overwrite geodatabase in ArcGIS Server 10 with ArcSDE for SQL Server?

text: I want to transfer a geodatabase from my development server to my client's production server. We are using SQL Server, but in different versions. Hence I cannot use Backup/restore or detach/attach. The servers don't have direct connection, so that I cannot copy the database. I used Moving a geodatabase using an XML document to export the database and then Import it to the destination. The export is done successfully, but since there are existing feature classes on the target database, I cannot import the data to the destination. I have to delete the existing features or overwrite the imported xml, but I don't know how.


title: Automatically georeference hundreds of png files based on polygon vector coordinates

text: I have 1000 polygons in my shapefile. I also have 1000 PNG files. Do you think it is possible (based on a common attribute), through a script or something, to assign each of those PNG files to a polygon? I am looking for an automated process which should "read" the polygon coordinates and based on that common attribute, it should somehow take the corresponding PNG, transform it in a tiff file and place it between the boundaries of that polygon? Basically, do the georeferencing for me ... I use mostly open source software and Global Mapper but I have no clue on how to do this.. Many thanks for the support,


title: Set size of map in PageLayoutControl to print ScaleBar underneath, not within map

text: For printing we have a PageLayoutControl where the user can select the map extent, he wants to print. I like the map to fill only a square in the middle of the page so that the title, the ScaleBar and some additional texts appear on top and underneath the map. By now the map fills the hole page. How can I resize the map? I tried setting the envelopes x and y values, but with no success:               public void SizeMap(IPageLayout pageLayout, IActiveView activeView)     {       IMap map = activeView.FocusMap;       IGraphicsContainer graphicsContainer = pageLayout as IGraphicsContainer;       IFrameElement frameElement = graphicsContainer.FindFrame(map);       IMapFrame mapFrame = (IMapFrame)frameElement;            IElement mainMap_Element = mapFrame as IElement;       IGeometry geometry = mainMap_Element.Geometry;       IEnvelope mainMap_Envelope = geometry.Envelope;            mainMap_Envelope.YMin = 5; // only example values       mainMap_Envelope.YMax = 12;            activeView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);     }      Is this the right approach? Thanks in advance.


title: Difficulty to display WMS and Googlemaps layers using Geoext and ext

text: i have the following code on my html file:                       // World Geodetic System 1984 projection         var WGS84 = new OpenLayers.Projection("EPSG:4326");              // WGS84 Google Mercator projection         var WGS84_google_mercator = new OpenLayers.Projection("EPSG:900913");                          // create a map panel with some layers that we will show in our layer tree         // below.         layers = [];              layers.push(new OpenLayers.Layer.Google("Google Maps", {             numZoomLevels: 20                         , 'sphericalMercator' : true                 }         ));              layers.push(new OpenLayers.Layer.WMS(         "National Parks", "http://localhost:8080/geoserver/wms", {             srs: 'EPSG:4326',             layers: 'National_Parks',             format: 'image/png',             buffer:0         }, {             'isBaseLayer': false         }         ));              map = new OpenLayers.Map({             allOverlays: false  // If it is true then both the wms and the map layers will be included under the "Overlays" folder              });              mapPanel = new GeoExt.MapPanel({             region: "center",             center: new OpenLayers.Bounds(-16.08,49.06,6.76,58.74).transform(WGS84, map.getProjectionObject()),             zoom: 2,             map: map         });              map.addLayers(layers);      As the code is at the moment i can see the googlemaps layer at full extent (although i wanted it zoomed in at these boundaries -16.08,49.06,6.76,58.74) but i can not see the national parks wms layer. What i did was to add 'displayOutsideMaxExtent':true next to 'isBaseLayer': false on the wms properties. When i did that i could see tha wms layer on all zoom levels but i couldnt see googlemaps at all. when i was zooming in and out the googlemaps layer was appearing instantly and then it was going off. Does anyone have any idea where the problem might be? I am using Geoserver, Openlayers, GeoExt and ext. Thanks ![Image 1 - White background](http://i.stack.imgur.com/P6wyM.png) ![Image 2 - Google Background](http://i.stack.imgur.com/foGIO.png)


title: how do i know my pgrouting version?

text: Is there a way to know what version of pgrouting do I have? My OS is ubuntu 12.04. I want to know my pgrouting version because the 1.05 version has some issues with shooting start and the directed graphs and the last stable version wich has this algotihm is the 1.03


title: How to export vector features to grid using proxy and WFS protocol?

text: I am trying to export vector features (current view) as a grid, something like: http://workshops.opengeo.org/geoext/wfs/grid.html so far layer features are not being retrieved.. I got empty grid in the window. would anyone take a look and let me know if I miss something ?               gridPanel = new Ext.grid.GridPanel({              title: "Feature Grid",              store: new GeoExt.data.FeatureStore({              fields: [                  {name: "id", type: "int"},                  {name: "name", type: "string"}              ],                  proxy: new GeoExt.data.proxy.Protocol({                  protocol: new OpenLayers.Protocol.WFS({                      url: "http://IP/geoserver/wfs",                      featureType: "myLayer",                      featureNS: "http://mapmap.org",                      srsName: "EPSG:3857",                      version: "1.1.0"                  })              }),                      autoLoad: true                      }),                      sm: new GeoExt.selection.FeatureModel(),              width: 320,          columns: [              {header: "id", dataIndex: "id"},              {header: "name", dataIndex: "name"}          ]          });                   //window to display grid              var gridWindow = new Ext.Window({                    items: [                           gridPanel                             ]                  }).show();


title: importing data into CartoDB

text: I've tried several ways of bringing my spreadsheet into CartoDB (.csv, .xls, .xlsx). However I keep getting a message like: An error ocurred when importing your data Error 99999   Unknown   What about...   Sorry, something went wrong and we're not sure what. Try uploading your file again, or contact us and we'll try to help you quickly. I have no idea why the same dataset will import as a .csv, but when I open it in excel, change one attribute, save it and upload it again as a .csv or .xls, I get this error.


title: Intersection between two ADF GraphicsLayer

text: I know how to intersect features from a ADF Geometry with a map ADF GraphicsLayer, but this requires me to have **ONE LAYER** on the map and then use a spatial filter on it. If I have two GraphicsLayer which are NOT on the map, but they are the result of a query themselves, how can I intersect them and show the result? I can't add one of them to the map because I can't interfere with it, this should be done in memory and not prompted to the user nor messing with the TableOfContents Any idea on how to do that?


title: empty buffer qgis

text: Help! I am trying to use three buffers to select three different sets of polygons. The buffers are from a .txt file with lat and long in decimals. I made a shapefile using North America Albers (I live in Vancouver, Canada). The buffers appear as expected on the canvas and clearly encircle the correct polygons. The problem: vector > intersect produces an empty selection. The attribute table of the buffer shapefile contains only the three points I used to make the shapefile in the first place. What am I doing wrong? Thanks!


title: Data Interoperability or FME ESRI Edition?

text: I've been debating keeping our Data Interoperability licence or going with the full FME ESRI Edition. I'm looking for advice. Thank you. D


title: create a vegetation mask using Landsat 7

text: I'm working on a very large study area. The aim is to create a vegetation mask representing only pines. I'm using Landsat 7 images. Since the recordings were made in the winter it's pretty easy to distinguish the conifers from the rest, because everything else is covered with snow. Unfortunately I do not get a satisfactory result. What is the best methodology to get good results? I've tried to use a NDVI. Unfortunately, the results are bad. I have also tried to use a tasseled cap transformation. Unfortunately, I have no experience using TC, so I'm not sure how to interpret/use the results. I am using Erdas Imagine and ArcGIS. Do you have any tips on how I can solve the problem?


title: How to create random points outside polygons?

text: The tool Create Random Point is able to generate a certain number of points within polygons. I am wondering, given a bounding box, is there any way that I can generate random points outside those polygon?


title: Create polygon based on the spatial extent in arcgis

text: Is there anyway that I can input   1) The Coordinates System (projected is OK)   2) The boundingbox   and create a rectangle polygon based on these?


title: Is there a programmatic way to retrieve Landsat 8 Satellite Images?

text: I have not been able to find out this myself, but is there a way to programmatic access Landsat 8 Satellite Images? I know that I can go to USGS EarthExplorer to search and browse through the scenes, and even download them. But I do not want to download them to my own computer for two reasons, My internet is slow and my laptop have cooling issues. So instead I figure I want to transfer the images directly to a “cloud”-instance for data processing. I would also be nice if I could download and process these images as they become available from USGS. Is there a way this could be done?


title: How to retrieve latitude/longitude from Tiff with Geotools

text: I am new to Geotools and I have to work on project which includes a set of tiff image maps. In that I need to get latitude/longitude for a given point. Ex: When mouse click occurs I want to get the lat/long for the clicked point. I tried following code snippet               frame.getMapPane().addMouseListener(                 new MapMouseAdapter(){                     public void onMouseClicked(MapMouseEvent ev) {                              //DirectPosition2D pos = ev.getMapPosition();                         //System.out.println(pos.x + " " + pos.y);                         DirectPosition2D pos = ev.getWorldPos();                         System.out.println(pos.x + " " + pos.y);                          }                 }              );      Are these simply the X/Y coordinates for a given point? I appreciate your help, thanks.


title: How to split complex lines?

text: I want to edit some complex polylines, which I imported from my GPS. These polylines have many vertices and are selfintersecting many times. When I try to split these lines using the 'Split Features'-command the line is split on every selfintersect and not only where I draw the cuting line. What am I doing wrong? Any suggestions? I'm using QGIS 1.8 on Windows8 (64).


title: What is the relationship between ITRF and WGS84?

text: Why are there people saying that "I am using WGS84(ITRF96)"? There are newer version of ITRF. Will WGS84 follow it? If so, what will be the influence to us?


title: when should I use a web coverage service instead of a wms?

text: Having used WMS for years now, I am wondering what extra benefits there could be if I also offered WCS for certain raster datasets eg. DEM. I have geotiff DEMs which I have loaded into geoserver and the height value is readable by WMS-getFeatureInfo. If I displayed this as a wcs what would I gain? thanks for any help, Rob


title: What are best alternatives to Esri software for LIDAR data?

text: I will be working with LIDAR data soon and am wondering what are the best alternatives to Esri software in your opinion? Which are generally considered to be the tops and flops of the LIDAR Sofware range? ... including of course all open source solutions!


title: How to add content below the map with Javascript?

text: Is it possible to enable some container below the map with JVectorMap? I have some links for all states which needs to appear when user clicks on state. I am new with Javascript so please help me. For example, I have three links which needs to show when user clicks on Florida: www.google.com http://gis.stackexchange.com ebay.com How to define those links to be related to Florida? Links need to appear in the container when user clicks on that state.


title: How do I create a quick test/demo app with ArcGIS Mobile

text: We are trying to do a quick evaluation of ArcGIS Mobile 10 on Windows. Part of that is determining whether we can load online maps (like arcgisserveronline for example) and what the performance/rendering quality is like. We tried using the 9.3 TileServices example but it does not appear to work with 10.0. Anyone else tried anything like this? Anyone know any good links on how to quickly get started on displaying maps on mobile (without our own map server)?


title: Is there a DTM available for free somewhere?

text: To go a little bit further than the semantic question regarding DEM/DTM/DSM, I'd like to know if there is a free (of charges and use) **DTM** datasets? And what about resolution? As far as I know,only DSM are available to public for free. Thanks, simo


title: How to add layer to OpenLayers, but without it getting automatically added in LayerSwitcher Control?

text: I have a Openlayer web map with LayerSwitcher control added. I need this to switch some of my layers. But I am also adding and removing some layers, which are temperory and i donot want them added to the LayerSwitcher Control. So is there a way to add layer to OpenLayers, but without it getting automatically added in LayerSwitcher Control?


title: google maps V3 : in javascript api, render route obtained with web api

text: I have to obtain route directions with the Google maps v3 WEB (http request) api (computations are made server-side, based on this data, without client interaction, so no JS available). Then, the routes are sorted out with internal logic, and the server (apache/PHP) send a web html/js/jQuery page to the client, which displays a page with a Google map (displayed with JS (ajax) api) On this map, i would like to render the routes obtained earlier by the server with the web api. So I tried to give the DirectionsResult to the google.maps.DirectionsRenderer::setDirections() but it does nothing, and firebug doesn't trace any error (and google JS if obfuscated, of course) Yes, I first set the map with setMap(), and the directionsRenderer is initialized correctly, all that is OK ! It seems that de DirectionsResult is not the same when obtained from Web API and from JS API. Is there a way to "translate" it, so that it could be rendered ? The alternative would be to do the route computations again on the client side with the ajax api, only to render them, but I think this is stupid to recompute directions as I already have them; so I don't want to do it this way unless it is the only way. Thank you for your help !


title: Finding the max. zoom level containing imagery at a point in Google Maps?

text: Is there a way to find the maximum zoom level containing imagery at a point in GMaps? I'm wanting to automatically zoom my map in as much as possible when a user chooses a point, but sometimes there is no hi-res imagery (i.e. only level 18, not 21) at that point? Is there a way to know beforehand?


title: Where to buy training licenses for learning ArcObjects?

text: A client of mine wants me to do some work with C# and ArcObjects. However, I have no real experience with C# (or much ArcObjects except with Java to be honest). Rather than outsource the work, I thought I'd treat it as a _personal_ training opportunity, which I've not done for many years; can anyone recommend a cheap resource for purchasing ArcObjects (C#), or a method of buying one solely for training purposes (clients have their own copy)? I have chanegd this to outline I do not need, per se, training media, or details (although I am sure that will follow), but the actual software; I do nto want to shell out for commercial rates, if it is just for my own use.


title: Looking for free web service that calculates driving distance between 2 addresses

text: I'm looking for a free web service that gets an input of 2 addresses and returns an output of **driving** distance between the 2 points. In addition I'm looking for a web service that doesn't require submitting a domain in order to use it (like google's distance matrix web service). Thanks.


title: Positional changes bewteen MapInfo 7 and 10

text: I have just come across something bizarre and I can't explain it. I have programs for creating grid squares and for converting points to polygons based on an OS grid reference [GB BNG]. Recently we upgraded to version 10 having previously been on version 7. Some data needed updating based on a new protocol for the disclosure of a protected species. The data, using a new easting and northing was given a point and then run through the same polygon generating routine which creates a polygon based on the accuracy of the grid reference. When projected on current data and grids the newly created data is not aligned correctly. On further investigation all our data appears west 5 meters and 222 metres south of where it should be in MapInfo 10 but is in the correct position in MapInfo 7. I cannot see what it is that could be different or changed. All the data created in MapInfo 7 appears in the correct position but if it is generated in MapInfo 10 it is not. We've checked alignment against on-line OS data and what we seen in MapInfo 7 is correct! Some have suggested that MapInfo 10 is more accurate but a metre is still a metre and 10 metres from the projection origin is still the same 10 metres. Any thoughts?


title: How to select multiple segments along one roadway?

text: I have a roadway network shapefile which only contains the center line of the roadway. I'm trying to create directional roadways from the center line. So I use "Copy Parallel" to create roadways at both sides of the center line and then add attribute to specify the direction. This is not a good method since the length of the lines do not change, so the ends of each segment can't meet (See 1st pic). Is there anyway to do it like tracing? Another problem is that after adding the parallel lines, I need to specify the direction of the parallel lines (whether it is northbound or southbound roadways). Since one roadway is consist of multiple segments, it takes a lot of time to manually select roadway of one direction. I can't use "Select By Attribute" since it is difficult to differentiate the parallel lines after copying and pasting.So I'm wondering if there is a way to select the whole road (multiple segments) by picking the start and end point of the roadway (So all segments directly connect to each other will be selected)? Any suggestions would be very much appreciated. ![Copy Parallel](http://i.stack.imgur.com/M0Xsc.jpg) ![Select Centerline](http://i.stack.imgur.com/DpKn0.jpg)


title: How does one calculate distortion on Equirectangular Projection?

text: I am trying to calculate distortion so I can distort overlaying text and forms to precisely match an image of an equirectangular projection. So, how does one calculate the distortion at a given latitude on an equirectangular projection 1:45,000,000 (say, 2000 pixels wide x 1000 pixels high)? I've been trying to figure out this post and its links to no avail: How to create an accurate Tissot Indicatrix? I am not a professional, just a very interested amateur, so please dumb it down for me! Many thanks! * * * Thanks for the prompt replies! Here's the long story; I hope it is clearer. I am visualizing/mapping data using the Processing programming language and would like to have the 2D mapped data (different sized fonts and circles) appear undistorted when wrapped to a 3D globe. The data is mapped using equirectangular x, y's and the maps I want to use as backdrops are all this projection, so I'm assuming I want to "match" this distortion (e.g. by calculating distortion via latitude using Tissot equations?). Using the programming language I can precisely distort both the text and the circles. I think all I need are the equations to do it correctly. Here is the original 2D data map: ![enter image description here](http://i.stack.imgur.com/IjnOw.png) When wrapped it looks distorted, like this: ![enter image description here](http://i.stack.imgur.com/drRRZ.jpg) The $10,000 Question: How can I make my 2D image look undistorted when wrapped to the 3D sphere? For reference, here's the same question asked differently on the Processing forum. Thanks again! * * * If I understand you correctly I'm not sure I want to reproject to an orthographic projection. I want my 2D data map to wrap to a 3D sphere model that can be interacted with (i.e. spun). I am using a 3D modeling program (Cinema 4D) to wrap a sphere with a 2MB "Blue Marble" image (equirectangular projection) from NASA. When wrapped it appears undistorted from all hemispheres (not just one hemisphere, as an orthographic projection would be?), see: still from 3D model above. (The modeling program is doing the orthographic projection for me as I rotate the object, I suppose.) Therefore, I think that if I distort my 2D data map in a similar way it too will appear undistorted on the 3D sphere. Here's a shot I took with an equation that approximates equirectangular distortion. You'll notice the egg shaped ellipses from the 2D image look like a circle when wrapped to the 3D sphere. Similarly, the Tissot ellipses also appear as circles on the 3D sphere. ![Tissot Indicatrix with distorted circles](http://i.stack.imgur.com/0y6uS.png) ![Distorted circles wrapped to 3D sphere](http://i.stack.imgur.com/PGyrR.png) This is why I was looking at the Tissot equations...to more precisely figure out the distortion of the equirectangular projection at different latitudes so I could distort my overlay accordingly. Hope this all makes sense. Perhaps you're right that I should use a GIS program. I just downloaded Cartographica and will see if I can figure it out. Any Mac software suggestions for a newbie undertaking this task? Thanks again.


title: How to determine if point is surrounded using raster processing?

text: I am attempting to improve a currently extremely cumbersome vector/python process for a natural hazard model. At the moment we have a lengthy script which generates distance/bearing lines from a given point to determine:   1. the type of polygon that it intersects (e.g.. Forest, grass, swamp, etc)   2. the distance to that polygon   3. how many of these lines intersect polygons, to determine how 'surrounded' it is. There's a lot more involved but that's the gist of it. I am trying to find a way to improve this and am currently stumped on part 3. The idea is to determine if a point is completely surrounded by polygons, within say 200m![PointA is surrounded, whilst PointB is only ~50% surrounded](http://i.stack.imgur.com/1BlF2.jpg) So in my attached image, I would want point A to be marked as being at higher risk than point B as it is completely surrounded by my polygons. This is repeated for about 13 million points so is not a small task and I would rather have a surface to derive values from, rather than running our script. I'm thinking there's got to be a variation of hydrology tools or cost-path to do this but I can't seem to get my head around it. Some assistance/suggestions on the best way to go about this would be MUCH appreciated.


title: Postgis - extrude a polygon

text: I want to extrude a polygon shape in postgis to create a pseudo 3D effect. To this end I have written a crude function to achieve it. This is very much test code and it creates a new Y vertice for each point on the polygon and then closes it by returning to the original point:-               CREATE OR REPLACE FUNCTION public.extrude_polygon(wkb_geometry_param geometry, height integer, simplify boolean DEFAULT false)       RETURNS geometry AS      $BODY$     DECLARE     f int;     ret_geom geometry;     wkb_geometry geometry;     BEGIN          --convert polygon to linestring     IF ST_GeometryType(wkb_geometry_param) != 'ST_Polygon' THEN          RETURN NULL;     END IF;          IF simplify THEN         wkb_geometry =         ST_Simplify(ST_Transform(ST_Exteriorring(wkb_geometry_param), 27700), 0.5);     ELSE     wkb_geometry = ST_Transform(ST_Exteriorring(wkb_geometry_param), 27700);     END IF;          --initialise output geometry     ret_geom =ST_MakeLine(ST_PointN(wkb_geometry,1),ST_PointN(wkb_geometry,1));          --Move first point to up          SELECT ST_AddPoint(ret_geom,           ST_MakePoint(ST_X(ST_PointN(wkb_geometry, 1)),                         ST_Y(ST_PointN(wkb_geometry, 1)) + height)     ) into ret_geom;          FOR f IN 1..ST_NPoints(wkb_geometry) LOOP         IF f < ST_NPoints(wkb_geometry) THEN         --across to next high point         SELECT ST_AddPoint(ret_geom,                    ST_MakePoint(ST_X(ST_PointN(wkb_geometry, f + 1)),                     ST_Y(ST_PointN(wkb_geometry, f + 1)) + height)         ) into ret_geom;         --down to next point         SELECT ST_AddPoint(ret_geom, ST_PointN(wkb_geometry,f + 1)) into ret_geom;         --back to last point         SELECT  ST_AddPoint(ret_geom, ST_PointN(wkb_geometry,f)) into ret_geom;         --back then up again         SELECT ST_AddPoint(ret_geom, ST_PointN(wkb_geometry,f + 1)) into ret_geom;         SELECT ST_AddPoint(ret_geom,                    ST_MakePoint(ST_X(ST_PointN(wkb_geometry, f + 1)),                     ST_Y(ST_PointN(wkb_geometry, f + 1)) + height)         ) into ret_geom;     ELSE         --across to first high point         SELECT ST_AddPoint(ret_geom,                    ST_MakePoint(ST_X(ST_PointN(wkb_geometry, 1)),                     ST_Y(ST_PointN(wkb_geometry, 1)) + height)                ) into ret_geom;              SELECT ST_AddPoint(ret_geom, ST_PointN(wkb_geometry,1)) into ret_geom;          END IF;     END LOOP;          RETURN ST_Buffer(ST_Buffer(ST_MakePolygon(ret_geom),10), -10);               END;          $BODY$       LANGUAGE plpgsql      It works with simple polygons but has problems with interior rings, but the main issue is that it is really slow. I need to output the resultant shape as a polygon that can be shaded and rendered in mapserver. Hence the buffer operations at the end which is the only way I know of reducing the shape to it's outline. The end result will be an extruded shape representing the original polygon. I can then offset the original polygon by the same extrusion distance and place it on top to make the roof. ![enter image description here](http://i.stack.imgur.com/t1KBT.png) I considered using the ST_Extrude function in postgis-2.1.1 BUT this creates a ST_PolyhedralSurface type and I am not able to render it in mapserver. As far as I can tell there is no way to create an outline of this either as ST_Buffer does not work with ST_polyhedralsurfaces. So, my question is, can my function be improved? Or is there a better approach. The output needs to look as per the diagram which I created by placing the offset polygon onto my extruded shape.


title: GetFeatureInfo on TMS layer with OpenLayers

text: I'm using OpenLayers.Layer.TMS to display external layers that have a different projection than EPSG3857/EPSG900913. I followed this tutorial. Now I can't use OpenLayers.Control.WMSGetFeatureInfo or OpenLayers.Control.WMTSGetFeatureInfo controls so how to handle getFeatureInfo request with my TMS layers?


title: Can I create, union and intersect 3D multipatch features using 3D Analyst extension (ArcGIS 10)?

text: I'm on ArcGIS 10. According to all the documentation I've read, 3D Analyst _should_ be able to do what I am trying to get it to do, but I am running into problem after problem and I'm almost ready to give up and find a simpler way to answer the question I'm being asked. In a nutshell, I have several layers I need to intersect or union in 3D. Some are points (thousands of them, which each represent a 3D volume, either a cube or a sphere, the dimensions of which are attribute values), some are polygons. I'm pretty sure the 3D Union and 3D Intersect tools only work on Multipatch features so I need to convert all of them to Multipatch features first. The main problem I'm having so far is that the 3D Analyst Union and Intersect tools refuse to operate on Multipatch features that are not "closed", and I can't seem to force ArcGIS to create Multipatches that _are_ closed. I've tried converting my one polygon layer (8 features) to a Multipatch both by extruding it in Arcscene using its height and converting that to multipatch and also using the "Extrude Between" tool, and they both produce some multipatches that are closed and some that aren't. I tried converting my points to spheres, using an example I found on ESRI's site here: http://www.esri.com/news/arcuser/1010/3danalysis.html Which tells you to symbolize the points as spheres, using an attribute as the radius, then use the "Layer 3D To Feature Class" tool to make them into multipatches. That also produces multipatches that are not closed and therefore useless. I haven't tackled converting points to 3D cubes yet. So if anyone knows a way to reliably create closed multipatches from 2D polygon layers and/or center points (with attributes describing the dimensions), let me know. Any alternative software solutions would be great too, I'm not tied to ESRI. Indeed, after mucking about with this for the last few days and realizing that ESRI's own tools create multipatches that _can't be used_ with many 3D Analyst tools, an alternative would be preferable. ETA: What I'm ultimately after is to calculate the volume of space that is occupied by (for example) cubes with a an attribute value of X where they intersect spheres with a value of Y (of course, I have lots and lots of values of X and Y to run).


title: R or QGIS? Measuring elevation at points on DTM surface

text: Based on answers to this recent question I have been able to create natural looking digital terrain models using a combination of `raster`, `rasterVis` and `rgl` working on data held in ESRI ASCII grid files. Next I want to measure the the height (elevation) of points on the surface of the digital terrain model. Ultimately I am interested in establishing the height of certain points on the hills compared to the floor of the valley nearby. Obviously, I could look at the data in the ASCII file - this is raw elevation data, after all - but it is impossible to relate the points in the plot to the data in the file. I would like to be able to visually inspect the plot, click on a point and read off the elevation, then click on another point and read that elevation. While plotting the data in R has been very easy, I can't think of any obvious way to measure heights using an R-based solution. Perhaps Quantum GIS is a better tool in this case? Suggestions on how to approach this using either R or QGIS would be appreciated. Image showing what I'm after and the code used to produce it follow below. (NB I do not have permission to reproduce the original DTM data, hence the mathematical surface.) ![surface](http://i.stack.imgur.com/7gaZl.jpg)               # Create an ESRI ASCII raster grid and plot it.     # For details of format, see:     # http://goo.gl/lsKNm7          out.file <- "your_file_name_here.asc"          num.cols <- 50     num.rows <- 50          # Mathematical surface taken from ?persp example     x <- seq(-10, 10, length.out = num.cols)     y <- x     rotsinc <- function(x,y) {         sinc <- function(x) { y <- sin(x)/x ; y[is.na(y)] <- 1; y }         10 * sinc( sqrt(x^2+y^2) )     }          my.mat <- outer(x, y, rotsinc)          # Create header as per format specs     header.df <- data.frame(variable = c('ncols','nrows','xllcorner','yllcorner','cellsize','nodata_value'),                             value = c(num.cols,num.rows,378923,4072345,2,-9999))          fileConn <- file(out.file)     write.table(header.df,                 quote = FALSE,                 row.names = FALSE,                 col.names = FALSE,                 sep = " ",                 file = fileConn)          # Append matrix to file     fileConn <- file(out.file, open = "a")     write.table(my.mat,                 row.names = FALSE,                 col.names = FALSE,                 file = fileConn)          close(fileConn)          # Now we can plot     library(raster)     library(rgdal)     library(rasterVis)          my.raster <- raster(readGDAL(out.file))     plot3D(my.raster,            smooth = FALSE,            specular = "black")


title: Why is the exterior shell of this GeoJSON invalid?

text: I got some data from Zillow's neighborhood database as shapefiles and converted them to GeoJSON. However, some of the objects appear to be malformed when inserting them into MongoDb. Is there anything obvious incorrect with this object? If not, I'll post to a mongodb group. I get the mongodb error `Exterior shell of polygon is invalid` Here is the GeoJSON that validates on http://geojsonlint.com               { "type": "Polygon", "coordinates": [ [ [ -118.446969222686, 34.0469016326594 ], [ -118.434190835956, 34.0504320311002 ], [ -118.430613269546, 34.0514987186012 ], [ -118.423933835946, 34.0574851170443 ], [ -118.423199406258, 34.0549809139169 ], [ -118.422660125007, 34.0533079256341 ], [ -118.421636562507, 34.0524724295396 ], [ -118.421512675788, 34.0512202381322 ], [ -118.41717327344, 34.046211074065 ], [ -118.416411648439, 34.0466005350029 ], [ -118.412196886716, 34.0489869060989 ], [ -118.409930683589, 34.0502700193813 ], [ -118.406049503898, 34.0526248670397 ], [ -118.405972386711, 34.0526120701647 ], [ -118.405962628898, 34.0526126092272 ], [ -118.405960624992, 34.0526101170397 ], [ -118.405959847648, 34.0526091482897 ], [ -118.405959847648, 34.0526099881335 ], [ -118.405960624992, 34.0526101170397 ], [ -118.405962624992, 34.0526126092272 ], [ -118.405668488273, 34.0526288904772 ], [ -118.405687144523, 34.0526748201648 ], [ -118.406090394523, 34.0535528201656 ], [ -118.405981945304, 34.0540129959473 ], [ -118.405474109366, 34.0542725857913 ], [ -118.40546691796, 34.0549122811044 ], [ -118.405903062492, 34.0549061678231 ], [ -118.405825968742, 34.0556394139175 ], [ -118.405820851554, 34.0571164373564 ], [ -118.399104050767, 34.0571106834502 ], [ -118.39054288279, 34.0571204920439 ], [ -118.38356623044, 34.0570572772001 ], [ -118.383860707003, 34.0544064764164 ], [ -118.384332789034, 34.0504714412565 ], [ -118.385436363254, 34.0487181834424 ], [ -118.389399999977, 34.0347272732731 ], [ -118.391367691385, 34.0301953865501 ], [ -118.391625523416, 34.0300484412375 ], [ -118.392837789042, 34.0295663865495 ], [ -118.393894082012, 34.0291868552992 ], [ -118.397096902327, 34.0289949412365 ], [ -118.399457230455, 34.029248132643 ], [ -118.404499855459, 34.0296909529559 ], [ -118.407776429681, 34.030082620925 ], [ -118.411082187497, 34.0307397263944 ], [ -118.415095054688, 34.031983468583 ], [ -118.418410257816, 34.0320081951455 ], [ -118.422025265632, 34.0318939295204 ], [ -118.426063460948, 34.0318955701454 ], [ -118.429185390639, 34.0317586248328 ], [ -118.432878500017, 34.0313464529574 ], [ -118.433469000018, 34.0314239021762 ], [ -118.436109089864, 34.0337636365534 ], [ -118.43832727346, 34.0371181795253 ], [ -118.446969222686, 34.0469016326594 ] ] ] }


title: Should OGR2Layers plug-in respect layer transparency?

text: When I export a graduated style layer from QGIS Dufour to OpenLayers using the OGR2Layers plug-in and QGIS rendering the colors and categories come across correctly. However, the opacity in the HTML is set to 1, where it should be .3 in my example . Am I doing something wrong, or does OGR2Layers not handle transparency? It's easy enough to edit the transparency in the HTML, but if there's a direct way, that would be nice.


title: sending a XAPI-Request to the API-Server - over http

text: pretty new to Geo-Informatics so do not bear with me if my questions sound like newbie-questions: can i do some requests on POIs of Openstreetmap with XAPI. doing like so: i send a request to the API-Server - over http as a respond i get the following result - in XML **example:** the following link gives back all the Nodes of the Type amenity=restaurant in XML-Format.Note: the bounding box (bbox) limits the area:               http://xapi.openstreetmap.org/api/0.6/node[amenity=restaurant][bbox=9.4908142,48.7810801,9.5660019,48.8387351]      see here the results:_               <?xml version='1.0' standalone='no'?>     <osm version='0.6' generator='xapi: OSM Extended API 2.0' xmlns:xapi='http://www.informationfreeway.org/xapi/0.6' xapi:uri='/api/0.6/node[amenity=restaurant|fast_food|pub|cafe][bbox=9.4908142,48.7810801,9.5660019,48.8387351]' xapi:planetDate='20100824' xapi:copyright='2010 OpenStreetMap contributors' xapi:license='Creative commons CC-BY-SA 2.0' xapi:bugs='For assistance or to report bugs contact 80n80n@gmail.com' xapi:instance='zappyOsm'>      <node id='721241970' lat='48.830856' lon='9.5116892' user='mabe75' timestamp='2010-05-04T19:01:28Z' uid='260302' version='1' changeset='4607010'>      <tag k='amenity' v='restaurant'/>      <tag k='name' v='Lamm'/>      </node>      <node id='392682646' lat='48.8315734' lon='9.5468864' user='MattGPS' timestamp='2010-05-11T19:00:20Z' uid='12973' version='3' changeset='4671372'>      <tag k='amenity' v='restaurant'/>      <tag k='name' v='Gasthaus an der Wieslauf'/>      </node>      <node id='319597380' lat='48.8277913' lon='9.5477029' timestamp='2008-12-17T21:13:15Z' version='1' changeset='444629'>      <tag k='amenity' v='restaurant'/>      <tag k='name' v='Gasthaus zur Linde'/>      </node>     [...]      well this example does not work here... what do ido wrong **update:** although this page doesn't explicitly say where xapi.opentreetmap.org points to these days, it does say that jxapi.openstreetmap.org (which it might point to) is down for maintenance right now. However, Mapquests's jxapi instance should be up, so we should be able to do that. Well actually i did a try and did just this:               wget http://open.mapquestapi.com/xapi/api/0.6/node[amenity=restaurant][bbox=9.4908142,48.7810801,9.5660019,48.8387351]      and it works. Note that there's an extra "/api" in the Mapquest xapi URL. The bbox is currently limited to 10 square degrees. See the various links from the XAPI wiki page for more info, including the terms of service for the Mapquest instance of the XAPI. Any idea how i can delimit the bbox - in order to run over a whole town like Hamburg or Berlin or lemme take Paris for example **By the way**. How to get the results stored in a databasse- note i have to convert the xml to a db-sheme.. mysql is preferred- any idea and helping hand is greatly appreciated


title: How can we work with QGIS Server on Windows?

text: I want to work with QGIS Server on Windows. I have not information about properties in this area. Where should I start? Thank


title: How to get the signal when the color changes in pyQGIS?

text: I would like to have the signal when the color of a vector layer is changed by the user. In the doc, there is a signal that seems to fit (http://qgis.org/api/classQgsVectorLayer.html#a403f235d3743aa59bb3aad69a72a5705) but nothing happens when it is called. I have a method called rendererChanged: `QObject.connect(self.iface.activeLayer(), SIGNAL("rendererChanged()"), self.DoSomething)` When executed, my function DoSomething is not executed. I have also tried : `self.iface.activeLayer().rendererChanged.connect(self.toto)` But I get this error : `AttributeError: 'QgsVectorLayer' object has no attribute 'rendererChanged'`


title: White lines in merged GeoTIFF files after ImageMosaicing on GeoServer

text: I have merged 21 GeoTIFF images using GDAL utilities. Each image is the result of merging 500 smaller tiles. I am using ImageMosaic in Geoserver but I am getting a mosaic that contains white lines and distortions. The lines and distortions become smaller and finer when zooming in. ![enter image description here](http://i.stack.imgur.com/umk9o.png) ![enter image description here](http://i.stack.imgur.com/qgftZ.png) What could be the reason behind having those white lines? The commands that I used are:               gdalbuildvrt -srcnodata 255 -vrtnodata 255 -a_srs EPSG:27700 -input_file_list tiff_list.txt mosaic.vrt          gdal_translate -of GTiff -co TILED=YES -co BIGTIFF=YES -co COMPRESS=JPEG -co JPEG_QUALITY=80 -co BLOCKXSIZE=512 -co BLOCKYSIZE=512 -co PHOTOMETRIC=YCBCR mosaic.vrt mosaic.tif          gdaladdo mosaic.tif -r average --config COMPRESS_OVERVIEW JPEG --config JPEG_QUALITY_OVERVIEW 60 --config INTERLEAVE_OVERVIEW PIXEL --config PHOTOMETRIC_OVERVIEW YCBCR 2 4 8 16 32 64 128 256 512      Thank you in advance


title: "System not initialized. Programmer forgot to call G_gisinit()." message when loading table into GRASS via QGis

text: I am trying to load a CSV table into Grass with `v.in.ascii`from the interface of Qgis 2.0.1 on Windows XP. As the progress bar indicated 74% of the data already loaded, I got the message `"System not initialized. Programmer forgot to call G_gisinit()."`. From that moment on, the loading stops. There is no further error message, the progress bar just gets stuck at 74%. The exact command was: `v.in.ascii input=N:/my_path_here/AREA_NOAS04_17_131004.csv output=t7j format=point "fs=;" skip=1 x=1 y=2 z=9 cat=0` I also tried loading the CSV table into QGis, then importing the resulting vector layer (points) into GRASS with `v.in.ogr.qgis`, with the exact same problem (same message, loading stops at 74%). If that helps, I'm using the CSV file contained in the Zip archive at the bottom of this page. I'm able to load other vector layers from Qgis into GRASS without problems. Might the large size of the dataset (4'128'498 points) be a cause of the problem? I tried to google the error message, but without any helpful results. Does anyone know what this message means and how I can solve this problem? Thanks a lot!


title: How to meet "Contour plugin" and "Profile Tool" dependencies in OSX?

text: So I have two similar but different issues than my previous question, one I may have mentioned already. When attempting to install the Contour plugin I am told I need matplotlib, which I have on my system (v. 1.1.1). Also, the Profile Tool is telling me I need Qwt5...I have no idea what this is. I posted earlier about needing Shapely.wkd for the Profile from Line tool, and received a response that the issue has to do with incompatibility between pyQwt5 and pyQwt. The Contour plugin does not seem to be related to the Qwt5 issue. Is it possible there is a suite of python modules I am missing on my install? Install: KingChaos 1.8.0 Lisboa System: MacOSX 10.7.5 Thanks much for the help. I really enjoy QGIS, but I want it to work correctly.


title: Problem with convert georeferenced jpg to geotiff

text: I'm beginner with GIS tools. I have jpg file with GPS data and I need reference this file to Microstation as georeferrenced raster. I tried use function Raster -> Conversion -> Translate with defined target SRS but without success. When recieved geotiff is referenced to Microstation he is not visibile. It is visible when SRS is set in Microstation model but problem is that raster lands on 0,0 coordinates. I enabled GDALTools plugin. Thanks in advance for help. Regards, Krzysztof


title: Will there be QGIS for Playbook?

text: Does anyone know if a mobile version of QGIS is planned for the Blackberry Playbook. I know there is an android version, I tried converting it to .bar and gave up when it wouldn't load because it needed Minstro to configure. Any help here would be appreciated.


title: Is dynamically changing a datasource possible in arcgis js api?

text: I've posted a related question is in the ArcGIS Desktop forums, but hasn't gotten any replies yet. In that case, I would like tackle this in another way, which is dynamically changing a datasource using arcgis js api. Is this possible? To give some detail, the layers defined in my mapservice are joined with another view through oledb. Will the class QueryDataSource be able to do this, and how?


title: Programmatically determine ArcGIS Layer(*.lyr) file version

text: I've been through IStorage, Microsoft Compound File Spec, ArcObjects deserialization etc. trying to detect the .lyr file version. Using ArcObjects, I can get at the Layer properties, data source, extent, etc, but the documentVersion property of the LayerFileClass always reports back 'esriArcGISVersion10' on 9.3 Layer files.               ILayerFile l = new LayerFileClass();     l.Open(fileName);     LayerFileClass t = (LayerFileClass)l;     string version = t.DocumentVersion.ToString();      Any help is appreciated. Note this crusty forum post from 2007.


title: Layer 3D to Feature Class Empty Output

text: I'm trying to build 3D buildings from 2D footprints. I extrude by the building heights, and input the surface by editing the properties. From here I use the Layer 3D to Feature Class tool to convert to multipatch. However the output from this results in a seemingly empty feature class, with no entries in the Attribute Table. I've tried saving the extruded buildings as a layer and using that as input to the Layer 3D to Feature Class tool, producing the same result of an empty feature class. Am I missing something about this tool? Thanks for any help.


title: Why has Web Mercator (auxiliary sphere) become the web map standard?

text: I understand what the difference is between the Web Mercator projection and Web Mercator Auxiliary Sphere (WMAS). I also understand that both Google and Esri have adopted this projection as their primary projection for their web- maps which is why we have specialized functions that not only re-project between all projections, but are specific functions for WM, such as webMercatorToGeographic. So ultimately I was wondering **why we use the WMAS projection, and the reason it has become a standard in web mapping.** Is it a purely a result of two spatial giants moving in that direction or was it just solely because of accuracy reasons? Additional Links:   Mercator Projection


title: How to dynamically update a KML layer in OpenLayers 2.10?

text: Arguably, this is a easy question for you guys GIS expert. Here is the question, how to outsource a dynamic KML file using JavaScript in OpenLayers. I want to refresh every 7 seconds. Below are snippet of the given codes:               <script type='text/javascript'>          var map;          OpenLayers.IMAGE_RELOAD_ATTEMPTS = 3;          function init() {         map = new OpenLayers.Map({             allOverlays: true,             controls: [                 new OpenLayers.Control.Navigation(),                 new OpenLayers.Control.PanZoom(),             ]         });              var osm_layer = new OpenLayers.Layer.OSM();         map.addLayer(osm_layer);              var MyKML = "http://www.xyz.com/tld/mypath/myfile.kml"              map.addLayer(new OpenLayers.Layer.GML("KML", MyKML,                 {                 format: OpenLayers.Format.KML,                  formatOptions: {                   extractStyles: true,                    extractAttributes: true,                   maxDepth: 1                 }                }));              // Adding controls to map           map.addControl(new OpenLayers.Control.ScaleLine());         map.render('map_element');              map.setCenter(                 new OpenLayers.LonLat(101.587008,3.021612).transform(                     new OpenLayers.Projection("EPSG:4326"),                     map.getProjectionObject()                 ), 17             );           }     </script>      The KML file could refresh automatically in Google Earth but not in OpenLayers. That is the real problem. And one huge complexion is I cannot visualize the KML layer in OpenLayers. Either I use static or passive KML file is quite successful. Anybody? Thanks in advance.


title: How to invert a Buffer(get the inside of a ring buffer)?

text: I have a line layer of a road network around which I create a buffer zone of 1000 m with Analysis Tools>Proximity>Buffer. But I am interested in the areas outside the buffer zone, and not the buffer zones themselves. Is there a way to invert the buffer, or which is the best way to pick out the the polygons outside the buffer area?


title: Why shapefile loaded in canvas always appear in random color?

text: I created the simple frame .UI file, compiled with pyuic4, and tried the ShapeViewer.py to load the shapefile "world_borders.shp". However, the map is always loaded in different random colors every time I rerun the python program. Why is this so? I tried loading the map in QGIS program & it loaded consistently with the same colors.               #! /usr/bin/env python          from PyQt4.QtCore import *     from PyQt4.QtGui import *     from qgis.core import *     from qgis.gui import *     import sys, os          # Import our GUI.     from shapeviewer_gui import Ui_MainWindow          class ShapeViewer(QMainWindow, Ui_MainWindow):       def __init__(self):         QMainWindow.__init__(self)              # Required by Qt4 to initialize the UI.         self.setupUi(self)         self.layers = []              # Set the title for the app.         self.setWindowTitle("ShapeViewer")              # Create the map canvas.         self.canvas = QgsMapCanvas()         self.canvas.useImageToRender(False)              # Set the background color to white.         self.canvas.setCanvasColor(Qt.white)         self.canvas.enableAntiAliasing(True)         self.canvas.show()              # Lay our widgets out in the main window using a vertical box layout.         self.layout = QVBoxLayout(self.frame)         self.layout.addWidget(self.canvas)              actionZoomIn = QAction(QString("Zoom in"), self)         actionZoomOut = QAction(QString("Zoom out"), self)         actionPan = QAction(QString("Pan"), self)              actionZoomIn.setCheckable(True)         actionZoomOut.setCheckable(True)         actionPan.setCheckable(True)              self.toolbar = self.addToolBar("Canvas actions")         self.toolbar.addAction(actionZoomIn)         self.toolbar.addAction(actionZoomOut)         self.toolbar.addAction(actionPan)              # Create the map tools.         self.toolPan = QgsMapToolPan(self.canvas)         self.toolPan.setAction(actionPan)         self.toolZoomIn = QgsMapToolZoom(self.canvas, False) # false = in         self.toolZoomIn.setAction(actionZoomIn)         self.toolZoomOut = QgsMapToolZoom(self.canvas, True) # true = out         self.toolZoomOut.setAction(actionZoomOut)              self.pan()              # Layout is set - open a layer.         # Add an OGR layer to the map.         self.Add_Map_Layer("qgis_data/world_borders.shp")              self.connect(actionZoomIn, SIGNAL("triggered()"), self.zoomIn)         self.connect(actionZoomOut, SIGNAL("triggered()"), self.zoomOut)         self.connect(actionPan, SIGNAL("triggered()"), self.pan)            def zoomIn(self):         self.canvas.setMapTool(self.toolZoomIn)            def zoomOut(self):         self.canvas.setMapTool(self.toolZoomOut)            def pan(self):         self.canvas.setMapTool(self.toolPan)            def Add_Map_Layer(self, mapFileName):         # Add the layer         if mapFileName == "":           layer = QgsVectorLayer()         else:           layer = QgsVectorLayer(os.path.abspath(mapFileName), mapFileName[mapFileName.rfind("/")+1:-4], "ogr")              if not layer.isValid():           print "Layer failed to load! :("           return              # Add layer to the registry         QgsMapLayerRegistry.instance().addMapLayer(layer);              # Set extent to the extent of our layer         self.canvas.setExtent(layer.extent())              # Set up the map canvas layer set         self.layers.append( QgsMapCanvasLayer(layer) )         self.canvas.setLayerSet(self.layers)          def main(argv):       # create Qt application       app = QApplication(argv)            # Environment variable QGISHOME must be set to the install directory       # before running the application       qgis_prefix = os.getenv("QGISHOME")       if qgis_prefix == None:         qgis_prefix = "/usr"            # Initialize qgis libraries       QgsApplication.setPrefixPath(qgis_prefix, True)       QgsApplication.initQgis()            # create main window       wnd = ShapeViewer()       # Move the app window to upper left       wnd.move(100,100)       wnd.show()            # run!       retval = app.exec_()            # exit       QgsApplication.exitQgis()       sys.exit(retval)          if __name__ == "__main__":       main(sys.argv)


title: Click link inside Leaflet Popup and do javascript

text: I have a leaflet map up and running. It overlays a series of polygons (via GeoJSON) on the map and attaches popups to each polygon. Each of the popups display information about that polygon. I'd like to have inside the popup a link that, when clicked, runs a javascript function that pulls further smaller polygons via AJAX and shows them. I can't get the script to catch a click on the link via the normal jQuery/Javascript click events. Here's what I mean by normal (the following doesn't work):               $('a .smallPolygonLink').click(function(e){       console.log("One of the many Small Polygon Links were Clicked");     });      The bindPopup part is as follows. It runs on each polygon when made and it pops up correctly on clicking on a polygon. It does show the link, just won't run the above code on click.               var popupContent = "Basic Information..." + 'Click here to see the smaller polygons';     layer.bindPopup(popupContent);      Any help is appreciated.


title: What GIS tools and packages are needed to find out nearby users in android application?

text: I'm building a location based android application with following _requirements_ :   1. Need to find out nearby users(i.e users using the same application)   2. Need to find out users in the state   3. Need to find out users in the country All the processing will be done on the server side. The android application will communicate with the server through web services. **What tools and packages do I require to achieve these requirements?** I'm new to GIS. My preferences are java and free software.