title: How can I do client side linear referencing in an Esri Silverlight/WPF app?

text: I have an Esri Silverlight/WPF UI with a mapcontrol and a slider. In the mapcontrol is a graphics layer with a single polyline on it, created using coordinates from a layer in a mapservice. The shapefield of the featureclass used by the mapservice has PolylineM's. I would like to find a way to move a point marker graphic along the polyline to reflect the M position as derived from the slider. The min and max values of the slider are the MinM and MaxM values of the polyline.


title: How to calculate flight line intersections?

text: I am new to GIS, and I have flight lines and I am interested in determining the crossover or intersection of those lines. Can I use QGIS for that and what would be the procedures for doing it?


title: How to Display Local Basemap Tiles from ArcGIS for Server Using OpenLayers?

text: I am using the OpenLayers JavaScript API within a web application. I generated a basemap tileset using ArcGIS Server for a particular region and i wrote a code to display the basemap tileset using OpenLayers. But whenever i load the webmap it shows the tiled images as pink and its not displaying... Can someone please help out?![enter image description here](http://i.stack.imgur.com/htwxf.png) Here's the sample code:               <!DOCTYPE html>     <html lang='en'>     <head>     <meta charset='utf-8' />     <title>Olabode Olushi OpenLayer</title>     <script type='text/javascript' src='OpenLayers.js'></script>          <script type='text/javascript'>          var map;          function init() {          map = new OpenLayers.Map('map_element', {});          cacheLayer = new OpenLayers.Layer.ArcGISCache( "ArcGISCache",                         "http://localhost:6080/arcgis/rest/services/Shane/Niagara_Cache_Example/ImageServer", {                             isBaseLayer: true,                              });          map.addLayer(cacheLayer);          map.addControl(new OpenLayers.Control.LayerSwitcher({}));     map.addControl(new OpenLayers.Control.PanZoomBar({}));                    map.zoomToExtent();          }          </script>     </head>          <body onload='init();'>     <div id='map_element' style='margin: 0; width: 1570px; height: 740px; box-shadow: 0px 5px 5px 3px #6B9000'>     </div>     </body>     </html>


title: "Enable Attachments" tool in ArcGIS 10.2.1 for Desktop

text: I am working through the tutorial for Arc Collector - Step 8, which says : To allow users to take pictures in the field and attach them to their assessment reports, enable attachments on the feature class you just created. To do so, right-click the feature class in the Catalog window, select Manage, and click Create Attachments. This is supposed to be available under the Data Management Tools - but all I see is a Photo tool, which does not appear to work the same way. Step 1 - need to "Enable Attachments" - but can't find the right tool Step 2 - right click feature class in catalog window....   Other users posted that you cannot add attachments to geodatabases with Desktop version, then why is this an instruction under this tutorial, which is for Desktop version...? Any help, greatly appreciated.


title: Properly clipping shapefiles in QGIS

text: I'm looking for help getting the correct shapefile. I'm working off of the files provided by the canadian government at http://geobase.ca/geobase/en/search.do?identifiant=&region=mb&produit=nhn&language=en These are identified as all the shapefiles that touch inside the Manitoba border. I've joined these files together and am attempting to clip them by another shapefile we have of the Manitoba border (Another tech created this by getting the entire Canadian border and cutting it down) My issue is, every time I clip it, the file returned always appears to be blank, despite the lengthy time it takes to create the file. I'm entering the input layer as the water layer, and the clipping layer as the border layer. We are working out of QGIS. Any help is appreciated. Any links for a good resource on this type of thing would also be appreciated. I personally have little to no GIS training, and this is just a small portion of a much larger project that we unfortunately have no one else to handle. Also I should note that I have made sure that the CRS match and I've also fixed all validity errors. EDIT: I meant to say validity, not integrity


title: Align line shapefile to base shapefile

text: I'm using Arcgis 10.1 and i have two line shapefiles. I know there is a way to make one shapefile follow the contour of the base shapefile but i cant figure how it is done. How can I make the blue shapefile lines align with the brown base lines? In other words apply the line configuration to the blue shapefile based on proximity? ![](http://i.stack.imgur.com/gpdB1.jpg)


title: arcpy.ListDatasets() returns emtpy list

text: I'm having trouble getting the ListDatasets (or any of the list functions) to return anything but an empty list when pointed at our SDE geodatabase, but the same code works for a file geodatabase. I searched how to connect to the SDE GDB and I can't see a mistake. I know the connection file works, I can open it with Catalog and log in just fine and it has a saved password with it. I'm at a loss, which means I have probably done something stupid. Help?               # Import arcpy module     import arcpy     from arcpy import env          env.workspace = r"F:Replicated Data\Auto_Extract_Connection.sde"          datasetList = arcpy.ListDatasets()          print datasetList          env.workspace =  r"F:\Replicated Data\Gatekeeper_Extract.gdb"          datasetList = arcpy.ListDatasets()          print datasetList      Returns: [] [u'ElectricDataset', u'CPUDataset', u'TransmissionDataset']


title: Convert Road layer shapefile into a graph

text: I'm going to use Astar algorithm to find a path between two selected points.And I used the following code for that.Is there any way I could convert my Road Layer shapefile into a graph, which can be use in this function? I'm new to QGIS and please help me to find a solution to this problem.               def astarSearch(self, graphAstar, current, end):         openSet = set()         openHeap = []         closedSet = set()              def retracePath(c):             path = [c]             while c.parent is not None:                     c = c.parent                     path.append(c)             path.reverse()             return path              openSet.add(current)         openHeap.append((0,current))         while openSet:         print "come2"             current = heapq.heappop(openHeap)[1]             if current == end:             print "come3"                                return retracePath(current)             openSet.remove(current)             closedSet.add(current)             for tile in graphAstar[current]:             print "come4"                     if tile not in closedSet:                         tile.H = (abs(end.x-tile.x)+abs(end.y-tile.y))*10                          if tile not in openSet:                                 openSet.add(tile)                                 heapq.heappush(openHeap, (tile.H,tile))                         tile.parent = current         return []


title: How to calculate X and Y projected coordinate in batch processing

text: I have more than 1000 shape files (all are point features). They were initially in WGS 84. I projected them in UTM. Then through batch processing I added X, Y fields in each table. But all the X, Y fields are now empty or rather filled with 0. I need to calculate X, Y projected coordinate through batch processing and fill newly added X, Y fields. I checked in calculate field option for batch processing under data management tool. But don't see any calculate geometry option there. Where can I find the tool in the tool box so that I can use it for batch processing all my tables to calculate X, Y in meters. I am using ArcGIS


title: How to change the settings for where ArcGIS splits world data

text: I have a world map made up of 6 shp files. All the files and the data frame are set to WGS84. The way Arc 10 and 10.1 decides to display the files, it splits Russia into 2. The majority of Russia can be seen to the East, however, one small bit is displayed at the western extent of the map. This is a single polygon. Is there a way to change the way ArcGIS treats this data so the the whole of Russia is displayed to the east? (I will eventually need to print the data). ![enter image description here](http://i.stack.imgur.com/KZNQo.jpg) EDIT: I'm starting to think that in order to do this I might need to create a new coordinate system (a copy of wgs84) and offset the centre of it so that it sits to the east. Thoughts?


title: ArcPad get vbs script location

text: Within arcpad (edit form) I want to get the current location of the vbs script running. This simple vbs script outside of arcpad works fine.               wscript.echo " " + Wscript.ScriptFullName      However, when I call this statement within a button click event in arcpad is gives and error and says object wscript required. I also tried this:               Dim sCurPath     sCurPath = CreateObject("Scripting.FileSystemObject").GetAbsolutePathName(".")     Application.MessageBox(sCurPath)      However, I'm getting > C:\Users\username\Desktop directory (not location of vbs script). Any ideas of how to find current directory of vbs script running in arcpad edit form? Thanks


title: ArcMap is Corrupting my Map Templates

text: Yesterday ArcMap crashed and corrupted the toolbar layout of a map I used as model. ![Corrupted](http://i.stack.imgur.com/qiAU5.png) No TOC, the Menu bar is on the left, ... Nothing dramatic, so I replaced them to something that is more of my liking: ![Normal](http://i.stack.imgur.com/l93Je.png) I saved, closed my map (to save the display in my Normal.mxt) and reopened the map. I was back at its corrupted "look"! I deleted my Normal.mxt template. Open ArcMap, and it was ok. I added the toolbars I use the most, saved it and made a copy of my Normal.mxt. If I open an new map, the display is fine. If I try to open any existing map (even one created a couple months ago), the display is "re-corrupted" but I know I was fine in that document. I used a script to create 45 maps from the model mentioned earlier, so I expect to them to have the corrupted layout (didn't notice this before creating them). But I don't want to have to replace all my toolbars everytime I open a map I created before. Never had that behavior before. I look like it's the same question as "ArcMap changing toolbars", but I didn't find an answer there for me. Thanks!


title: How do I remove unwanted attributes from spatial join using ModelBuilder?

text: I am new to ArcGIS 10 and am currently building a model. This is a brief rundown of what I am doing at the moment. I have 2 shapefiles: one a polyline and the other is point data. I have joined both files using the spatial join tool within the model which created a shapefile that contains the attributes of both files. But I would like to get rid of the attributes obtained from the polyline and retain the attributes from the points since the shapefile has changed to a polyine. Thanks


title: Works (publicly available) combining LUCAS with other European land data bases?

text: EUROSTAT provides the LUCAS dataset, a multi-purpose survey on the state and the dynamics of changes in land use and cover in the European Union. I wonder if there are any land classification projects (preferably public works), that make use of the LUCAS data base in combination with other (European-wide) geospatial data (remotely sensed or else) and/or land (cover and/or use) data bases. In particular, I am interested in a nomenclature correspondence between LUCAS and other European schemes. For examle, an attempt to assess CORINE's thematic accuracy using the LUCAS data set, is described in Fine scale profile of CORINE Land Cover classes with LUCAS data.


title: How can I relate between street and city in OSM imported data into SQL?

text: I've used OSM2MSSQL to fill db with 2 cities streets. Now I have the following tables in my DB :               tNode      tNodeTag     tRelation     tRelationMember     tRelationTag      tTagText      tWay      tWayCreation      tWayTag       How can I get all the streets that are in a specific city ?


title: Modifications to labeling engine is not supported in the QGIS composer?

text: I' using QGIS 2.0 but this problem was also present in Qgis 1.8. I have a truetype font of freeway symbols that I use to label polylines. Each symbol requires between 3 font characters to display correctly. For this reason, each character has a field and I have duplicated the shapefile 3 times and use a different field for the label each time and overlap the labels. In the labeling engine, we can change the number of label candidates to 1 to force labels to overlap and this works great in the QGIS map canvas (working environment - see picture 1 below) but it's not working in the composer. The composer shows the three labels side by side instead of overlapping (see picture 2 below). In QGIS 1.8, with labeling from the layer properties menu (that is now deprecated if I'm not mistaken) worked fine with overlapping labels but it would create "static" labels. The labeling from the layer menu creates "dynamic" labels that move around with zoom level. I would like to have overlapping dynamic labels that also work in the composer. If anyone knows how to make the labeling engine also work in the composer, I would be very grateful. ![Correctly overlapping labels](http://i.stack.imgur.com/PrfT0.png) ![Labels not overlapping in composer](http://i.stack.imgur.com/sIAXG.png)


title: Dissolve Statistics Fields and Statistic Type as Parameters in GeoProcessor

text: I have a published service which uses a dissolve. In arcMap the I get prompted for all the fields, including statistics fields and stat type. I have the statistics fields marked as parameters. However, when I publish the service to arcgis for server 10.1 all parameters show except the stats fields in the parameter list on server. When I try to run the service through the javascript api it uses the field names and types I used just prior to publishing it. Which, of course, works fine if I pass features with the same name. Is it possible to publish a service with a dissolve which makes the stats fields and type a parameter that is accessible by arcgis javascript api?


title: grass plugin in QGIS all of sudden not working as expected

text: The previous week I was able to use the grass scripts in the QGIS 2.0.1 Dufour toolbox, but today they do not seem to be working. I am not sure where to place a '-c' which was a solution to the same error presented, by which the grass plugin is not outputting the layer and the grass configuration and installation seems to be fine. My log states the vector map is not found and the info message states Number of lines as 0 which should not be the case as I was using the v.to.points function and all of my parameters were the same as when the function previously worked. In any case my other grass functions are also not working, yet the other plugins seem to be working. The temporary directory where all of my previous usages of grass plugins is full of folders with temporary output shapefiles, so I am unsure if that would be the root cause.


title: Coordinate System changes after reprojection

text: I have changed the projections of some Natural Earth Shapefile to "WGS 84/Pseduo Mercator", that works fine (after cutting out the artic), but now the co ordinates of the shapefile are all out of wack. I can display the shapefile(s) in my application (using MapWinGIS), but the lat longs that i'm passing for points etc are in decimal degrees and the shape file seems to be in something else - meters maybe? What can i do to keep the shapefile in degrees, or is there a conversation between to two.


title: Best way to figure out which regions a point is in a shape file?

text: I'm trying to figure out the best way on Android to figure out if a point in region as defined in a shapefile. For instance, I might want to know what country I'm in using the Geo Common's Shapefile file for Countries. Is there an existing Android library that can manage such tasks with Shapefiles, or an equivalent substitute (KML, for instance)? A few other points:   1. I might be using a lot of regions. For instance, I might want to know what county I'm in, along with state and country. Thus, there is potential for overlap of regions.   2. Speed is desirable, if possible. I might, for instance, figure out which country I'm in, then state, then county, and only look at the applicable states for a country, and counties for a state.   3. Compactness is very important. At least one of the data files I want to work with is 47 Mb as a KML, Shapefiles seems like a reasonable size, assuming I can find a decent library for it.


title: How to import OSM Data into mongoDB in easy way

text: Can any one tell me how to import OSM data in mongoDB step by step ? This is the link of data http://download.geofabrik.de/europe/germany/baden- wuerttemberg/karlsruhe-regbez.html * * * https://gis.stackexchange.com/users/12320/ylka![enter image description here](http://i.stack.imgur.com/iCPWt.png) this is the error i am getting in the 1 step


title: Determine the list of circles (from 100K circles), that overlap with a given polygon

text: This question was asked on StackOverflow, came here because no response has been posted so far. ## Existing data structure we have polygons represented as an ordered list of lat/long coordinates and circles represented as lat/long coordinates with radius, stored in PostgreSQL (no PostGIS extension):               CREATE TABLE polygon_point     (       id character varying(40) NOT NULL, -- The polygon id        orderno integer, -- Ordering on the points       latitude numeric(9,6), -- The latitude of this point in lat/long representation       longitude numeric(9,6) -- The longitude of this point  in lat/long representation     );               CREATE TABLE circle     (       id character varying(40) NOT NULL, -- The circle id        latitude numeric(9,6), -- The latitude of this circle in lat/long representation       longitude numeric(9,6), -- The longitude of this circle in lat/long representation       radius numeric(10,2) -- radius in meters     );      ## Cardinality polygons: 1000 circles: 10000-20000 ## Task for a given polygon, we'll need to determine the list of circles, that overlap with the polygon. ## Plan   1. choose an appropriate opensource Java library that can compute the bounding box of a polygon and also the relationship of a circle and a polygon (contains, within, disjoint, intersects). Something like GeoTools, spaital4j, etc. Never used any of them, recommendations are welcome.   2. calculate the bounding box of the polygon (use the library). Let's suppose the bounding box vertices are numbered clock-wise, starting from the upper right corner: (lat1,long1), ..., (lat4,long4)   3. modify the bounding box so that each edge is moved radius meters to appropriate direction (upper right corner is moved to north and east, ..., lower left corner is moved to south and west)   4. query the db and list circles that possibly overlap   Query would be something along these lines:              select * from circle     where latitude between lat2 and lat1     and longitude between long3 and long2          5. Now we have a limited list of circles. For all these circles, compute the relationship with the polygon (use the library again) ## Question What library should I use and is this plan feasible at all?


title: ST_Intersects returning incorrect result on routing problem

text: I have a table that contains the shortest path between destinations for survey respondents on an osm2po created network. When calculating the shortest path result, I store the geometry in a column. Now, using the same osm2po network table and each shortest path geometry, I am trying to determine whether the shortest path crosses or intersects a highway. I created another table that just contains the osm2po network with clazz 11-16 and run an `st_intersects(shortestpathgeom,highwaygeom)` and get all false results. The shortest path geometry is multilinestring and the highway geometry is linestring, both are SRID 4326 and have been created from the same table. Why am I getting no intersections? Here is a picture of the shortest path in purple, highway in green, osm2po in red. ![shortestpath\(purple\), highway\(green\), network\(red\)](http://i.stack.imgur.com/roI2E.png) here is my code where po_routing.route is the shortest path, po_highway.the_geom is highway only network, and obstacle is the intersection test.               update analysis.po_routing      set obstacle = st_intersects(route,b.the_geom)     from analysis.po_highway as b;      Any help would be greatly appreciated, I don't understand why this fundamental function is not working as expected.


title: 6 degree to 3 degree Transverse Mercator transformation

text: I am looking to plot coordinates that were given to me but I am having some issues projections. I currently have my data projected to NAD83 MTM 1, but the coordinates that were given to me are based in a 51 Degree West longitude of the 6 Degree Transverse Mercator Projection, NAD 83. Using ArcGIS, what projection would I use to do the transformation.


title: Can you access ArcScan from a python script?

text: I'm using a python script with ArcPy in ArcGIS 10, and want to access some ArcScan functions. Is this possible? I can't see anything in the documentation about it, but I can't really find any very good ArcPy documentation. **Update:** Just to add some extra information: I want to run the centreline vectorisation method (see here) from an ArcPy script. Is that possible?


title: How to cut a 'tiled image' from a raster dataset using GDAL?

text: I am working on an app that needs to create tiles (jpeg) from a given raster dataset. My initial inclination was to use gdal2tiles.py, but its performance seems like it could be improved. That leads me to ask the following question: What would be the fastest way to cut a 'tiled image' from a raster dataset using GDAL? And by 'tiled image', I mean just a simple jpeg or png. In my proto-type, I use the MapServer C# mapscript bindings to do the job. That is, I create a map object, loop through all the tile bounds I need to cut, set the map objects extent, and then save the resulting image. The performance of this approach is significantly better than that of gdal2tiles.py, but I am wondering if I use GDAL directly if I cant make it even faster. Can anyone suggest a similar workflow with GDAL methods? EDIT: After some more research today, I found the answer right in front of me. If you have downloaded FWTools, the csharp\apps folders contains a number of classes to demonstrate the C# GDAL bindings. In my case the GDALRead.cs and GDALReadDirect.cs were what I was looking for.


title: What is the maximum, allowable field length for a FacilityID field in a Cityworks geodatabase?

text: Over the past couple of months, I have seen a few esri-geodatabases and they seem to be either a text field with a length of 20 or 30. Is 30 the maximum field length? Clarification: The answer I'm looking for is if there is a Cityworks-specific constraint on the text field length in the esri geodatabase.


title: Google Street View with Image Only

text: Is it possible to open a location in Google Street View and have it show ONLY the Street View image? For example, if I open the following link: http://maps.google.com/maps?q=&output=svembed&layer=c&cbll=34.9032895146312,-82.3337301891165&cbp=0,0,0,0,0 I want to set the attributes so that the navigation tools, the full screen button, and the overview map button are all gone from the screen. If possible, I would also like to be able to remove the Google logo at the bottom left. Can this be done? Thanks, Seth


title: How can I update ogr2ogr to include the PostgreSQL driver?

text: I'm trying to use ogr2ogr to upload a shapefile to a remote PostGres installation. When I ran this command:               celenius:~ celenius$ ogr2ogr -f PostgreSQL PG:"host=255.34.00.00 user=postgres dbname=mydb password=***" Dropbox/data/roads.shp;      I got the following error message:               Unable to find driver `PostgreSQL'.     The following drivers are available:       -> `ESRI Shapefile'       -> `MapInfo File'       -> `UK .NTF'      ...       -> `SVG'       -> `CouchDB'       -> `Idrisi'       -> `ARCGEN'       -> `SEGUKOOA'       -> `SEGY'      (I omitted some of the drivers as they are not relevant). Is there a way that I can update ogr2ogr to include PostgreSQL? I'm using a Mac with OS 10.7.4


title: Dropdown menu to select vector layer from current displayed layers in qgis

text: I'm trying to write a python plugin to create an input file for an urban climate model out of three shape files. One of the shape files contains the buildings (polygon), one the trees (point), and the third one the center point of the new model input file (point). I therefore need a function to select one layer out of the currently displayed ones. I tried messing around with               qgis.utils.iface.legendInterface().layers()            but then I get some ugly output like `qgis.core.QgsVectorLayer object at 0xb4b6f5c`. Is there a possibility to get readable names out of this? Or is there an easier way to select the layers? Any ideas or help greatly appreciated!


title: Installing GarminCustomMap: "missing _gdal_array module" error

text: I've used the GarminCustomMap plugin in QGIS 1.8 without troubles. But now, with QGIS 2.0, when I try to install it, I get the following message "missing _gdal_array module". Any idea how to fix this? Thanks a lot! Roberta


title: How can I read binary PBF and bzipped XML OSM data in QGIS?

text: How can I read binary PBF OSM data, e.g. example.osm.pbf or bzipped XML OSM data in QGIS?


title: Which ESRI software is need to open MXD files?

text: I received a group of MXD, AHD, and XML files on a CD from a client. What is the least expensive ESRI software that would be needed to view the information contained in these files? I only need to view and print. Thanks! Rob


title: How to display a lot of images with OpenLayers?

text: I would like to display **a lot of images at same time**. The images are georeferenced (they have extents), with some labels on top of it which, on click, open popup. I can not say how many exactly because it will depends of user choices. And I want the user to choose the information he sees. There's some checkboxes he can check or not and it will display more or less images depending on his choices. My problem is that I have to deal with the "issue" (which actually is not really an issue) described in OpenLayers wiki: What is the maximum amount of layers I can have in my OpenLayers Map? I was wondering if there is a way to have more than 75 images. Because, the system actually works, except when I want to display more than 75 images: Popups and labels appear below images... I tried a long time to play with `z-index`, without success though. Thanks a lot.


title: ArcGIS - How to remove additional symbols on single points?

text: I have problems with a point data layer in ArcGIS (9.3). An additional symbol has appeared on some of the points within the layer which were recently created and checked-in from ArcPad. This additional symbol cannot be edited and has been placed on top of another symbol which I can edit normally using layer properties. I would like to remove the additional symbol and retain a single editable symbol for each point. Any advice on how to do this would be gratefully received. Edit #1: I have checked the map as suggested in the answer below and have multiple symbols on single points in a single layer. How do I remove the multiple symbols and return to a single editable symbol? Edit #2: The screenshot below shows an extract from the map (of trees). The blue circle is the editable symbol covering all points in the layer. The green circle is the additional non-editable symbol which has appeared for the most recently checked-in points. I have selected two points labelled Betula and Quercus. The selected point labelled Quercus has an additional green circle symbol, although that is not shown due to the selection highlighting. ![enter image description here](http://i.stack.imgur.com/NkXnI.jpg)


title: Calculating "relative slope" per Mora-Vahrson method in ArcGIS

text: I'm a longtime lurker who finally decided to register on the forum (in no way driven by my need to have a certain question answered, of course...). I was contacted by a colleague asking for help calcuating an input for a landslide model he's working on. Specifically, the model he's following (the Mora-Vahrson paper/model) asks for the slope input to be not in degrees or percents, but "relative slope." This is obtained by using the formula: **Sr= [(ElevMAX-ElevMIN)/(Area)]** , where the the min and max elevations are the lowest and highest points within a bounded area (most commonly 1 square km); these area searches/calculations are carried out across the desired study region without overlap. I've tried multiple ways to calculate this using my existing skillset (limited; I'm an archaeologist with a background in GIS who was asked to help out...) and program (ArcGIS). I'm using a 90m resolution SRTM DEM for the area and have currently settled on using the Block Stats tool to calculate the MIN (and the MAX) for for a specified area 1000 x 1000m, and then entering those resultant rasters into the Raster Calculator as part of the Mora-Vahrson equation), and dividing by 1 (as the area of the Block Stat calculation, expressed in square km). What I would like to gauge from more experienced GIS users is whether or not the Block Stats process I described seems to meet the requirements for the model's relative slope component. If anyone else has had experience calculating relative slope or a similar process, I'd be very interested to hear about it. Thanks.


title: How to render features with different symbols depending on in memory data?

text: We are developing a complex ArcMap extension software which contains class extensions, a workspace extension and some ArcMap extensions. The purpose of the software is to link our existing management sofware to the client's ArcGIS data. This way he can access our software's data without leaving ArcMap and without duplicating data. This way, some the client's data stays in their feature classes and our data is in a separate database, in another dbms. We have access to our systems's data inside the class extensions via some configurations made in ArcCatalog. We can easily put the needed data in memory for later use. We now have to implement advanced feature rendering(displaying different symbols for a featureclass) depending on data contained in our management software. On demand, we could fetch and store in memory the data needed to compute the symbol to draw for each feature. **Is there an exising renderer that I could use that works with in-memory data?** If not, **is there a way to temporarily add the in memory data to the feature class?** (add temporary in-memory fields) If it doesn't work I suppose that I need to create my own renderer. Where do I start?


title: Raster aggregation in ArcGIS

text: I'd like to aggregate a raster from 1m to 6m in ArcGIS with a custom rule. For example, each cell value of aggregated raster = mean value of 5 highest cell values from 36 aggregated values. How do I do that?


title: How can I use the proj string in java code?

text: I want to do projection from UTM/oblique mercator CRS to WGS84. And I know the solution to use a proj.4 string in commandline like`+proj=omerc +lat_0=51.4 +lonc=7 +alpha=-10 +k=1 +x_0=0 +y_0=0 +gamma=0 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs` However, I wonder if there is a way to do such transformation using plain code. I have configured the gdal jar for my eclipse and want to use the java bindings to do such transformation. From the OGR projection tutorial,I know how to define a Geographic Coordinate System and projected Coordinate Sytem with OGRSpatialReference class. I know how to define a transformation using OGRCoordinateTransformation class. But the only thing missing there is the possibility to customize my source UTM. I don't know how to set the lon,lat of my orgin point. I also don't know how to set the oblique angle. There seems to be no such pre-built method in the classes. Anyone can give me some hints? Thx for attention.


title: Can Elevation Profile data in Arc's Flex Viewer 3.0 be exported?

text: a related thread here: google earth profile used in mashup or flex Would like to export the elevation profile data (csv, txt, etc.) from Arc's Flex Viewer 3.0 as it creates one: ![Flex's Elevation Profile](http://i.stack.imgur.com/dUx6i.png) Also, if there is a way to do this export using Google Earth's Elevation Profile tool that would be helpful too. I know GPS Visualizer can do this with kml/gpx files but would like to have the ability to extract the data directly from Flex.


title: create a pie shaped object in shapely and export to gis polygon object

text: I would like to create a pie chart-shaped polygon with concentric layers like so: ![pie example](http://i.stack.imgur.com/05yAY.png) I can create this simple object with:               from math import sin, cos, radians      from shapely.geometry import Point,LineString          #variables for buffers     coordinates = (0,0)     point = Point(coordinates)     buffers=[]     outerRadius=100     numberOfCircles=5     radiusStep= outerRadius/numberOfCircles     innerRadius=radiusStep     pi=3.1415               #create the buffers     while innerRadius<=outerRadius:         buffers.append(point.buffer(innerRadius,200))         innerRadius+=radiusStep               #variables for linestrings      centerX = coordinates[0]     centerY = coordinates[1]     coordX=[]     coordY=[]     lines=[]          #create linestrings for circles     for i in xrange(1,361,45):         xCoord = centerX + outerRadius * cos(radians(i))         coordX.append(xCoord)         yCoord = centerY + outerRadius * sin(radians(i))         coordY.append(yCoord)         line = LineString([(centerX,centerY),(xCoord,yCoord)])         lines.append(line)      **My question is this:** How can I take multiple shapely objects of different geometries and create a geofile (geojson, shapefile, etc...) so that each section of the "pie" is treated as a separate polygon.


title: How to determine right side of the street vs left side?

text: ![Example picture](http://i.stack.imgur.com/3rIOi.jpg) Given the following information, how does the program determine which side is the even-numbered side of the street?


title: Convex Hull issue in QGIS 1.8

text: When creating convex hulls based on input field in qgis 1.8, there seems to be always one less convex hull created for the unique values in the input field. For example; I have a point vector file, and it has a field in its attribute table called 'type'. This field has two unique values, 1 and 2. When trying to create convex hulls for these types, only one convex hull is created, encompassing the 'type' value 2. The point vector file also has a field called 'year'. This field has three unique values, 2007, 2008 and 2009. When creating convex hulls for these types, only two convex hulls are created, encompassing 2008 and 2009 values only. I've tested this further with other vector files and it always seems to be the case that the lowest integer value is ignored when the convex hull process is run. I have also tested this with text based fields, it also creates one less convex hull than the number of unique variables in the text field. This issue was not present in previous verisons of qGIS. Can any of the developers or anyone else shed some light on this? As a workaround, a dummy feature has been included in the attribute table with an additional variable where its value is lower than that of the other unique variables. Thanks for your help.


title: Stats on individual grid points nearest neighbours

text: First, thank you for this extremely useful and easy-to-access forum! I have shp of points where each point is the centroid of the individual cells of a 1*1km grid (~ 500 000 points). For each of these points, I have their coordinates and elevation. What I want: for each of these points, I want to compute the mean, std dev, min, max and median elevation of the nearest 8 surrounding points. What I did so far: I wrote an R script to identify each of the nearest points for each of the points of the grid. But considering the size of the dbf and the general slowness of R, it takes forever. My tools: QGIS, ArcGIS, SAS, R or other free software if needed. Question: Does any one have a suggestion to do this (1- identify the direct neighbors, 2- compute summary stats from the elevation of these neighbors) in a more efficient way, using GIS? Thank you in advance! Helene


title: How do I set mmqgis create grid options?

text: I am having a puzzle about using mmqgis create vector layer option. I want to use UTM CSR![This are my options:](http://i.stack.imgur.com/BtqXf.png) this are my options. I want a grid of 20,000 meters in the east and north axis. Nevertheless i have an error screen stating: "invalid width/height 6.0/6.0". As I understand my settings I should have 6 lines separated by 20,000 meters Am I understanding this in the wrong way? Thanks in advance


title: Is a new map object required in order to create a wms overlay on top of a current map object with wfs layers using the leaflet api

text: I am trying to add a wms tile layer overlay over a wfs tile layer which I added to a map object. When I tried to simply add a layer on top of my current setView for my map object it overwrote the first layer's and all the GUI I added was gone. How do I add a wms tile layer overlay?


title: Unable to download osm2po from the original site

text: I've been trying to download the osm2po tool, in order to import the openstreetmap data into postgis database, from the original site and is impossible for me. All links I find in the page are cyclic, return to the main page and I can't find the way to access the tool. Any body can help me? Thanks in advance.


title: Problem adding a join to a table via Python using addJoin_management

text: I am currently building a script for a script tool that will join data from a multitude of tables into a single table based on a common join field. Now, I have attempted to use arcpy.addJoin_management(...) to join data from a `linkTable` to a `primaryTable`, and received the following tool error message (ERROR 000990):               arcgisscripting.ExecuteError: Failed to execute. Parameters are not valid.     WARNING 000970: The join field METER_GRIDNO in the join table Customer_Accounts is      not indexed. To improve performance, we recommend that an index be created for the     join field in the join table.     ERROR 000990: All_Meters is already joined     Failed to execute (AddJoin).      Here is the code leading up to the point of failure:               # Create table views or feature layers in order to join data using      # the Add Join tool.     if primaryTableIsFC:         arcpy.MakeFeatureLayer_management(_primaryTable, primaryTableView)     else:         arcpy.MakeTableView_management(_primaryTable, primaryTableView)     arcpy.MakeTableView_management(_linkTable, linkTableView)          # Join link table coordinates and other data to primary table.     arcpy.AddJoin_management(primaryTableView, _primaryJoinField,                               linkTableView, _linkJoinField, "KEEP_COMMON")      I have received this error message regardless of what tables or feature classes I use, and have tried inputting parameters of varying types into the tool to no effect. When I tried to "remove" the join indicated by the error message, I receive an error that the table `file cannot be opened`. What is strange is that there is no problem executing this code segment in ArcMap via the 'Python Window' when I use full path names to the files. From my own troubleshooting in ArcMap I have discerned that the Add Join tool will give this error when the only the join table basename for the feature class is supplied, but will work when the full path to the table is used. This is not the case outside of ArcMap however. For a relatively simple tool, it is surprising to be having such difficulties executing it inside of an IDE (Eclipse Juno, to be precise). If someone out there knows enough about the intricacies of the `arcgisscripting` module from which this tool operates to provide some insight as to what might be going wrong, I'd greatly appreciate the help. Also, I'm in the process of learning python scripting using arcpy, so if there is something simple that I missed, please let me know. Full Code Up to Error: From module `construct_analysis_fc`:               # Coded input of parameters, for debug and testing purposes     outputPath = (r"G:\Projects\Water_Resources\WaterEfficiencyTargeting" +                   os.path.sep + r"GIS_Data\WaterUseByBillingTier.gdb")     importDir = None     fileFilterList = None     outputName = "Customer_Accounts_Spatial"     primaryTable = "Customer_Accounts"     primaryJoinField = "METER_GRIDNO"     linkTablePath = (r"G:\Projects\Water_Resources\WaterEfficiencyTargeting" +                     os.path.sep + "GIS_Data\WaterUseByBillingTier.gdb\All_Meters")     linkJoinField = "METER_GRIDNO"     linkXYFields = ["LONGITUDE", "LATITUDE"]     linkOtherFields = []     joinTables = []     fieldList = ["Customer_No", "Account_No", "Service_Address",                   "Service_City", "Service_Zip","METER_GRIDNO",                   "Account_Type", "Adjustment_Form", "Read_Date",                  "Bill_Date", "Max_Tier", "Billing_Cycle_Days",                  "Bill_Number", "Billed_Consumption","Billed_Charges",                  "LONGITUDE", "LATITUDE", "Landscape_Area"                  ]     constructMethod = "XY_LINK"          # Prepare workspace and environment variables     if not scratchPath:         scratchPath = arcpy.env.workspace     scratch = workspace_setup.getScratchWorkspace(scratchPath)     arcpy.env.workspace = outputPath     arcpy.env.overwriteOutput = True          # Create geodatabase tables from imported table files.     if importDir:         import_xlsx_data.importXlsxData(importDir, outputPath, fileFilterList)          # Initialize data containers for processing     primaryTableInfo = [primaryTable, primaryJoinField]     linkTableInfo = [linkTablePath, linkJoinField, linkXYFields, linkOtherFields]     joinTablesInfo = fc_constructor.create_field_info_dict(joinTables, fieldList)          # Use methods of a `FeatureClassConstructor` class instance to build the     # desired output feature class.     fc_constructor_ = fc_constructor.FeatureClassConstructor(outputPath)          if constructMethod == fc_constructor.GEOCODE:         pass     elif constructMethod == fc_constructor.XY_LINK:         fc_constructor_.construct_xy_linked_fc(outputName, primaryTableInfo,                                                 linkTableInfo, False, joinTablesInfo)     elif constructMethod == fc_constructor.COMPREHENSIVE:         pass     else:         arcpy.AddError(constructMethod + " is an invalid construction method.")         exit(1)      From module `fc_constructor`:                def construct_xy_linked_fc(self, outputName, primaryTableInfo, linkTableInfo,                                writeUnmatched=False, joinTablesInfo=None):         """Join coordinate data from reference table to primary table and join         data from additional tables based on a common join field. Return a         feature class containing all specified input data.              The `primaryTableInfo` argument specifies the table to which spatial         information and all other data be joined to via a join field. It is         supplied in the following form:              primaryTableInfo = [<"tableName">, <"joinField">]              The `linkTableInfo` argument specifies a table containing coordinate         and optionally other data to be joined to the primary table, allowing         a feature layer to be exported to a feature class as output. It is         supplied in the following form:              linkTableInfo = [<"tablePath">, <"joinField">, <["xField", "yField"]>,                          <["fields"]>]              where <"tablePath"> is a complete path to the table, <"joinField">         is the field to join by, <("xField", "yField")> is a list of fields          specifying coordinate information, and <["fields"]> is a list of         fields to also be joined to the primary table. In the case where         the link table resides in the same workspace as the primary table,          <"tablePath"> can simply be the name of the link table.              `writeUnmatched` specifies weather to create a supplementary table          containing the link IDs of records in the primary table that have no          matching records in the link table.              `joinTablesInfo` specifies a dictionary of table name - field detail         tuple key-value pairs indicating what field data from other tables          should be joined to the primary table. It is supplied in the following         form:              joinTablesInfo = {<"tableName_01":[field_01, ...]>, ...}              where each `tableName` key is linked to a list of field names and types         to be joined to the primary table. All of the tables MUST have the same         join field as in the primary table in order to be joined.              """              env.workspace = self.outputPath         #curEnv = env.workspace              _outputFC = outputName + u"_spatial"         _primaryTable = primaryTableInfo[0]         _primaryJoinField = primaryTableInfo[1]         _linkTablePath = linkTableInfo[0]         _linkJoinField = linkTableInfo[1]         _linkXYFields = linkTableInfo[2]         if len(linkTableInfo) == 4:             _linkFieldNames = linkTableInfo[3]         env.workspace = os.path.dirname(_linkTablePath)         _linkTable = os.path.basename(_linkTablePath)         _linkFields = ([fields for fields in arcpy.ListFields(_linkTable)                          if fields.name in _linkFieldNames])         _linkFields.extend(_linkXYFields)              primaryTableView = _primaryTable + "_view"         linkTableView = _linkTable + "_view"         tempPrimaryXYLayer = _primaryTable + "_xy_lyr"              if writeUnmatched:             _unmatchedTable = _primaryTable + u"_Unmatched"             arcpy.CreateTable_management(self.outputPath, _unmatchedTable)             arcpy.AddField_management(_unmatchedTable, _primaryJoinField.name,                                        _primaryJoinField.type)              # Determine whether the input types are either tables or feature classes         primaryTableIsFC = False         if arcpy.Describe(_primaryTable).dataType == u"FeatureClass":             primaryTableIsFC = True              env.workspace = self.outputPath         #curEnv = env.workspace              # Create table views or feature layers in order to join data using          # the Add Join tool.         if primaryTableIsFC:             arcpy.MakeFeatureLayer_management(_primaryTable, primaryTableView)         else:             arcpy.MakeTableView_management(_primaryTable, primaryTableView)         arcpy.MakeTableView_management(_linkTable, linkTableView)              # Join link table coordinates and other data to primary table.         arcpy.AddJoin_management(primaryTableView, _primaryJoinField,                                   linkTableView, _linkJoinField, "KEEP_COMMON")      Additional information:   * ArcInfo License   * Version 10.0   * Service Pack 5 Thanks to those who can help!


title: How does a newbie get household income data based on address to the block level?

text: I am beginning a research project and need to find a way to access the census data about household income. We need it at a closer level than by zip code since income varies a lot by zip code in our area. Is there a way to get household income based on address or at least down to the block level? Any help and or links you have would be great. Thanks!


title: Integrate grid and polygon of municipalities keeping the biggest municipality per cell with QGIS (or another)

text: I have a 9x9 grid and a polygon of municipalities of an extensive area of Brazil. My goal is to have a field indicating the biggest municipality per grid cell. I've been trying with intercept without good results. I know there are similar questions but i cant figure it out how to handle it in QGIS. Here is a screenshot of what i'm talking about: ![enter image description here](http://i.stack.imgur.com/ULVk3.png) I was thinking that maybe with intersecton and then spatial union joining with maximum but it didnt work. I want to get the final grid with a field indicating the biggest municipality inside each grid cell. Thank you all in advance Sergio Now


title: Personal Geodatabase not recognized as valid datasource in the last QGIS Windows Weekly build (64 bits)

text: I was using Personal Geodatabases in QGIS without any problem but it's stopped to work since I installed the last 64 bits weekly build for Windows (1.9.0-35-Setup-x86_64). I'm now receiving an "Invalid datasource" error message. Is this problem related to the last weekly build or specific to the 64 bits version? **EDIT:** I confirm that it work on the last 32bit weekly build so the problem is specific to the 64 bits version... Thanks a lot Etienne


title: Calculate values to represent bus route attribute

text: I'm working with bus routes and looking for a way to represent some values in this system. I want each street to be represented by thickness based on value returned in SUM or COUNT. I don't have big issues with Symbology process but some getting those values. I have two layers:   1. Streets/roads. No overlapping lines. Topology OK. Attribute table with STREET_NAME, ID.   2. Bus lines. One feature per bus line/direction. Attribute table with variables for these lines like number of passengers, name, direction. Some lines, or part of them, are overlapping. What I did until now in ArcGIS:   1. Spatial Join with this two layers (one to many, match option WITHIN)   2. Dissolve by street’s name+ID. Trying to SUM some fields and COUNT another. Results:   1. Ok for SUM fields (p. ex. number of passengers)   2. COUNT return 0 when COUNT using LINE_NAME field (text). Solved by create a field (double) and fill with value “1” for each feature. Now COUNT or SUM function returns the number of bus routes over each street. Any help in this process, alternative or optimized way? I’m using ArcGIS and QGIS in this project. Thanks. UPDATE Attached some images with results using SUM on Dissolve function. I achieved what I wanted but I'm interested if there some better other option in this process. I´m not planning to build a Network now. Maybe in the future as I don't know if is possible to represent these infos in a Network Dataset. Thanks again. ![Streets](http://i.stack.imgur.com/ufxw8.png) ![Bus routes](http://i.stack.imgur.com/TWv0d.png) ![SUM on bus routes](http://i.stack.imgur.com/arvIf.png)


title: Drag marker from outside to leaflet map

text: > Is there any way to drag a marker from outside to the map using leaflet Api > . Any suggestions plese help me?


title: Displaying z-values in arcscene

text: Probably there is a very simple solution to my problem - I just can't find one! I have a point shapefile with x, y and z data - I can display it in arcscene but it is flat - the z data isn't being used! How can I direct arcscene to the z field in my attribute field so that it displays points at different levels?!


title: How can I symbolize a layer with graduated colors by a date/time field?

text: I've got a layer of polygons where each has a date associated with it. I want to color the polygons with graduated colors, but I want the colors to start with the newest polygons and fade to the oldest polygons. So far I haven't been able to find a way to do this in ArcMap (<= 9.3.1) other than to create a new field and calculate some integer or float value based on the date. Is it possible to use a date or time field directly?   * The data is natively a date-time value   * There are far too many records to use any unique-value renderer   * Converting the date to a numerical field is an answer for a different question.


title: Selecting Polygon Features in QGIS Lisboa

text: I want to select and save as a separate shape file, a smaller section (polygon) from a whole island country which includes both land and shallow habitat coastal features (like coral reefs) and when I draw and select a polygon, the indicated yellow selected area includes areas outside of the polygon I have drawn. What am I doing wrong so that I can select polygons that are subsections of larger maps without including these 'outside' areas?


title: Why does GRASS eliminate polygons when using v.generalize?

text: I am facing a dilemma while trying to use v.generalize to simplify polygons which are similar in size and structure to US Counties or States. Often, I lose polygons from the data set after running either a simplification or smoothing method on them. What troubles me is that there does not seem to be any consistent pattern to this behavior. In some cases the same set of commands applied to different data sets causes causes completely different results. As a result, I am unable to develop a repeatable workflow and am reluctantly starting to look for other simplification tools that preserve topololgy. Here is an example:               # LOAD AND CLEAN     v.in.ogr dsn=counties.shp output=county     v.build.polylines input=county output=county_polylines     v.clean input=county_polylines output=county_clean tool=bpol,rmdupl type=boundary          # SMOOTH AND GENERALIZE     v.generalize input=county_clean output=county_smooth method=sliding_averaging look_ahead=7 slide=1     v.generalize input=county_smooth output=county_general method=douglas threshold=.005      Each of the v.generalize steps results in some of the polygons disappearing. I'd like to understand why this happens. Is it due to features being loaded into insufficient memory? Are my parameters "tight" enough to cause features to be excluded because they've met some sort of geometry criteria? (Note that I'm losing some very large features.) Is there a problem with the topology of the dropped features which causes them to get erased? Related to that last question, I assume that build.polylines and clean operations that I do initially should take care of this, but I'm not entirely certain, and I can't seem to find good instructions that address this. Are there any? Appreciate any insights people can give, especially those based on personal experience with the v.generalize tool. Roger


title: How to add a print function to GeoExt MapPanel?

text: I´m trying to add a print function to my GeoExt MapPanel, using the following code:               bbar: ["->", {                         text: "Print...",                         handler: function() {                              var printDialog = new Ext.Window({                                     items: [new GeoExt.PrintMapPanel({                                         sourceMap: mapPanel,                                         printProvider: new GeoExt.data.PrintProvider({                                             method: "GET",                                              url: "/geoserver/pdf",                                                   listeners: {                                             "loadcapabilities": function() {                                             var printPage = new GeoExt.data.PrintPage();                                                 printPage.fit(mapPanel, true);                                                 printProvider.print(mapPanel, printPage);                                             }                                             },                                                 customParams: {                                                     mapTitle: "LVR WebGIS",                                                     comment: "created with GeoExt"                                                 }                                         })                                     })],                                     bbar: [{                                         text: "Create PDF",                                         handler: function() {                                             printDialog.items.get(0).print();                                         }                                     }]                             });                         printDialog.show();                         }                     }]      Using this code, I get the firebug error message               this.printProvider.layout is null      in line 240 of the PrintMapPanel.js               239  adjustSize: function(width, height) {     240  var printSize = this.printProvider.layout.get("size");     241  var ratio = printSize.width / printSize.height;       when trying to print the MapPanel. Do I have to add a size/layout definition somewhere in the code or in the config.yaml of the print provider? Any help is appreciated! Cheers, Philippe


title: Rename postGIS table and updating the GeoServer?

text: I want to rename one of my postGIS tables. However, when I do this by applying a simple               ALTER TABLE old_name RENAME TO new_name;      The spatial data, as I understand it, isn't updated with the new name. First, can these references be fixed by running the function:               SELECT probe_geometry_columns()      Is the table itself OK after this? Or should other measures be taken also? Second, how do I update GeoServer so that it finds this new table? As of now, if I run the above commands, _and_ edit the layer info on the GeoServer to point to the new name... I still get an error (GeoServer still tries to find it under the old name). Exactly, where should the layer name be changed on the GeoServer?


title: How to calculate oblique photo scale?

text: Is it possible to calculate oblique photo scale by given vertical photo scale ? I mean is there any kind formula relation between them or maybe is it possible to calculate rough approximation of oblique scale ?


title: How to start an ArcMap editing session without displaying the Editor toolbar

text: I'm developing a toolbar with some geoprocessing routines and digitizing functionality. On this toolbar I have implemented a "start edit" button. I want to start an edit session by clicking that button on my toolbar, but the original ArcMap Editor toolbar shows up too, even so I deselected it form the customize menu. Is it possible to prevent the Editor toolbar from opening, so users are forced to use my custom toolbar? (You can simulate my workflow by adding the "Start Editing" button to any toolbar in ArcMap's Customize mode. Note that the Editor toolbar always switches on when starting an edit session).


title: connecting cartodb to existing mysql database

text: I'm trying to create a simple heat map based on longitudinal and latitudinal map coordinates that can be transferred from a database on mysql that I've created. I read that cartodb can be connected to other databases, but I'm not sure how to go about doing that. Any help that could be provided would be greatly appreciated. Thanks for your time.


title: Raster to Vector: Displaying classes in Vector Layer - GRASS GIS

text: I use Maximum Likelihood classification to classify Landsat image into two landuse classes - one of my interest and rest including all others. Inorder to assess the accuracy I export it in vector format using `r.to.vect` with feature type as area. But I find no option to export it in such a way that I can differentiate between two classes. Is there any way to do that?


title: How to handle URLs longer that 2048 chars in JSAPI v2.7 and ArcGIS 10.2

text: In ArcGIS Server 9.3 and JavaScript API v2.4 there was need to set proxy.config in ASP.NET in order to handle requests to REST map services having more than 2048 characters in the URL as parameters. Is there any change in ArcGIS 10.2 and JS API v2.7 (or higher)? How the URLs longer than 2048 characters are handled in ArcGIS Server 10.2? Thanks.


title: Export to Mapbox (TileMill) from PSD (or SVG/PNG)

text: Newbie question: I designed a map (not Earth-related) in Photoshop and I want to use something like Mapbox to serve the map and make it dynamic (bounding boxes, zoom in/out, etc). How can I go from an SVG/PNG to a tile-based map? TileMill accepts as data input geoJSON, SQLite, PostGIS. For example:               {"type":"FeatureCollection","features":[     {"type":"Feature","id":"BRA","properties":{"name":"Brazil"},"geometry":{"type":"Polygon","coordinates":[[[-57.625133,-30.216295],[-56.2909,-28.852761],[-55.162286,-27.881915],[-54.490725,-27.474757],[-53.648735,-26.923473],[-53.628349,-26.124865],[-54.13005,-25.547639],[-54.625291,-25.739255],[-54.428946,-25.162185],[-54.293476,-24.5708],[-54.29296,-24.021014],[-54.652834,-23.839578],[-55.027902,-24.001274],[-55.400747,-23.956935],[-55.517639,-23.571998],[-55.610683,-22.655619],[-55.797958,-22.35693],[-56.473317,-22.0863],[-56.88151,-22.282154],[-57.937156,-22.090176],[-57.870674,-20.732688],[-58.166392,-20.176701],[-57.853802,-19.969995],[-57.949997,-19.400004],[-57.676009,-18.96184],[-57.498371,-18.174188],[-57.734558,-17.552468],[-58.280804,-17.27171],[-58.388058,-16.877109],[-58.24122,-16.299573],[-60.15839,-16.258284],[-60.542966,-15.09391],[-60.251149,-15.077219],[-60.264326,-14.645979],[-60.459198,-14.354007],[-60.503304,-13.775955],[-61.084121,-13.479384],[-61.713204,-13.489202],[-62.127081,-13.198781],[-62.80306,-13.000653],[-63.196499,-12.627033],[-64.316353,-12.461978],[-65.402281,-11.56627],[-65.321899,-10.895872],[-65.444837,-10.511451],[-65.338435,-9.761988],[-66.646908,-9.931331],[-67.173801,-10.306812],[-68.048192,-10.712059],[-68.271254,-11.014521],[-68.786158,-11.03638],[-69.529678,-10.951734],[-70.093752,-11.123972],[-70.548686,-11.009147],[-70.481894,-9.490118],[-71.302412,-10.079436],[-72.184891,-10.053598],[-72.563033,-9.520194],[-73.226713,-9.462213],[-73.015383,-9.032833],[-73.571059,-8.424447],[-73.987235,-7.52383],[-73.723401,-7.340999],[-73.724487,-6.918595],[-73.120027,-6.629931],[-73.219711,-6.089189],[-72.964507,-5.741251],[-72.891928,-5.274561],[-71.748406,-4.593983],[-70.928843,-4.401591],[-70.794769,-4.251265],[-69.893635,-4.298187],[-69.444102,-1.556287],[-69.420486,-1.122619],[-69.577065,-0.549992],[-70.020656,-0.185156],[-70.015566,0.541414],[-69.452396,0.706159],[-69.252434,0.602651],[-69.218638,0.985677],[-69.804597,1.089081],[-69.816973,1.714805],[-67.868565,1.692455],[-67.53781,2.037163],[-67.259998,1.719999],[-67.065048,1.130112],[-66.876326,1.253361],[-66.325765,0.724452],[-65.548267,0.789254],[-65.354713,1.095282],[-64.611012,1.328731],[-64.199306,1.492855],[-64.083085,1.916369],[-63.368788,2.2009],[-63.422867,2.411068],[-64.269999,2.497006],[-64.408828,3.126786],[-64.368494,3.79721],[-64.816064,4.056445],[-64.628659,4.148481],[-63.888343,4.02053],[-63.093198,3.770571],[-62.804533,4.006965],[-62.08543,4.162124],[-60.966893,4.536468],[-60.601179,4.918098],[-60.733574,5.200277],[-60.213683,5.244486],[-59.980959,5.014061],[-60.111002,4.574967],[-59.767406,4.423503],[-59.53804,3.958803],[-59.815413,3.606499],[-59.974525,2.755233],[-59.718546,2.24963],[-59.646044,1.786894],[-59.030862,1.317698],[-58.540013,1.268088],[-58.429477,1.463942],[-58.11345,1.507195],[-57.660971,1.682585],[-57.335823,1.948538],[-56.782704,1.863711],[-56.539386,1.899523],[-55.995698,1.817667],[-55.9056,2.021996],[-56.073342,2.220795],[-55.973322,2.510364],[-55.569755,2.421506],[-55.097587,2.523748],[-54.524754,2.311849],[-54.088063,2.105557],[-53.778521,2.376703],[-53.554839,2.334897],[-53.418465,2.053389],[-52.939657,2.124858],[-52.556425,2.504705],[-52.249338,3.241094],[-51.657797,4.156232],[-51.317146,4.203491],[-51.069771,3.650398],[-50.508875,1.901564],[-49.974076,1.736483],[-49.947101,1.04619],[-50.699251,0.222984],[-50.388211,-0.078445],[-48.620567,-0.235489],[-48.584497,-1.237805],[-47.824956,-0.581618],[-46.566584,-0.941028],[-44.905703,-1.55174],[-44.417619,-2.13775],[-44.581589,-2.691308],[-43.418791,-2.38311],[-41.472657,-2.912018],[-39.978665,-2.873054],[-38.500383,-3.700652],[-37.223252,-4.820946],[-36.452937,-5.109404],[-35.597796,-5.149504],[-35.235389,-5.464937],[-34.89603,-6.738193],[-34.729993,-7.343221],[-35.128212,-8.996401],[-35.636967,-9.649282],[-37.046519,-11.040721],[-37.683612,-12.171195],[-38.423877,-13.038119],[-38.673887,-13.057652],[-38.953276,-13.79337],[-38.882298,-15.667054],[-39.161092,-17.208407],[-39.267339,-17.867746],[-39.583521,-18.262296],[-39.760823,-19.599113],[-40.774741,-20.904512],[-40.944756,-21.937317],[-41.754164,-22.370676],[-41.988284,-22.97007],[-43.074704,-22.967693],[-44.647812,-23.351959],[-45.352136,-23.796842],[-46.472093,-24.088969],[-47.648972,-24.885199],[-48.495458,-25.877025],[-48.641005,-26.623698],[-48.474736,-27.175912],[-48.66152,-28.186135],[-48.888457,-28.674115],[-49.587329,-29.224469],[-50.696874,-30.984465],[-51.576226,-31.777698],[-52.256081,-32.24537],[-52.7121,-33.196578],[-53.373662,-33.768378],[-53.650544,-33.202004],[-53.209589,-32.727666],[-53.787952,-32.047243],[-54.572452,-31.494511],[-55.60151,-30.853879],[-55.973245,-30.883076],[-56.976026,-30.109686],[-57.625133,-30.216295]]]}}     ]}      However, I don’t have those coordinates to define the polygon area. Any ideas? Thanks!


title: normalizing Haversine distance

text: I need to normalize the Haversine distance. What's the maximum Haversine distance ? The Earth circumference I guess ? how much is it ? thanks


title: Setting the map projection in the flex API to an overlay layer

text: I'd like to use a basemap containing world map data as a backdrop to some point and outline data that I'm hosting in ArcGIS server in the ESRI Flex API, but I would like the map control to share a WKID with my data, so I don't need to reproject it on every operation. However, the Map control seems to want a) the layers to be displayed with the first being on the bottom, and b) the first layer to be the layer that defines the WKID. Is there a good way to work around these contraints?


title: Bilinear interpolation of point data on a raster in Python?

text: I have a raster that I'd like to do some point interpolations with. Here is where I'm at:               from osgeo import gdal     from numpy import array          # Read raster     source = gdal.Open('my_raster.tif')     nx, ny = source.RasterXSize, source.RasterYSize     gt = source.GetGeoTransform()     band_array = source.GetRasterBand(1).ReadAsArray()     # Close raster     source = None          # Compute mid-point grid spacings     ax = array([gt[0] + ix*gt[1] + gt[1]/2.0 for ix in range(nx)])     ay = array([gt[3] + iy*gt[5] + gt[5]/2.0 for iy in range(ny)])      Up to now, I've tried SciPy's interp2d function:               from scipy import interpolate     bilinterp = interpolate.interp2d(ax, ay, band_array, kind='linear')      however I get a memory error on my 32-bit Windows system with a 317×301 raster:               Traceback (most recent call last):       File "<interactive input>", line 1, in <module>       File "C:\Python25\Lib\site-packages\scipy\interpolate\interpolate.py", line 125, in __init__         self.tck = fitpack.bisplrep(self.x, self.y, self.z, kx=kx, ky=ky, s=0.)       File "C:\Python25\Lib\site-packages\scipy\interpolate\fitpack.py", line 873, in bisplrep     tx,ty,nxest,nyest,wrk,lwrk1,lwrk2)     MemoryError      I'll admit, I have limited confidence in this SciPy function, as the `bounds_error` or `fill_value` parameters don't work as documented. I don't see why I should have a memory error, since my raster is 317×301, and the bilinear algorithm should not be difficult. Has anyone come across a good bilinear interpolation algorithm, preferably in Python, possibly tailored with NumPy? Any hints or advice? * * * (Note: the nearest neighbor interpolation algorithm is easy cake:               from numpy import argmin, NAN          def nearest_neighbor(px, py, no_data=NAN):         '''Nearest Neighbor point at (px, py) on band_array         example: nearest_neighbor(2790501.920, 6338905.159)'''         ix = int(round((px - (gt[0] + gt[1]/2.0))/gt[1]))         iy = int(round((py - (gt[3] + gt[5]/2.0))/gt[5]))         if (ix < 0) or (iy < 0) or (ix > nx - 1) or (iy > ny - 1):             return no_data         else:             return band_array[iy, ix]      ... but I much prefer bilinear interpolation methods)


title: QGIS WKT Raster Plugin error, what does this mean?

text: I have been playing with the WKT Raster plugin. I have installed the WKT Raster experimental binaries in PostGIS successfully and followed the instructions in the read me to the letter. When i am in QGIS I use the WKT Raster plugin to "Load Raster to PostGIS" everything seems to run fine there but once completed I get this error below. ![Error message I receive after loading raster to postGIS](http://i.stack.imgur.com/oxcbx.png) Even though I get this error the table shows up in PostgreSQL and I can load it into QGIS but it does appear empty/blank. I checked in PostgreSQL and the table is there and it has values in it. Also the error message says "DbError: relation '' already exists", but its the first time I have ever created a table with that name in the DB. Any ideas? Thanks Ando


title: Image viewer or browser for large images

text: I have some big images. I'm looking for an easy way to browse and view them. Currently I'm using Preview.app on OS X, but it wasn't designed for these types of images. My images are, for example:   * .JP2, 42 MB, 50,000 x 30,000 pixels   * a 3.4 GB TIF   * something in NITF format etc.


title: How to install QGIS on Centos 6?

text: I'm new on this; I really tried a lot before ask.. but nothing works. I did all that the qgis page says. Install ELGIS. after that i investigate and tried diferents comands.. but nothing works..the last I tried was:               yum --enablerepo=elgis install qgis      this was the response:               Loaded plugins: fastestmirror, refresh-packagekit, security     Loading mirror speeds from cached hostfile      * base: mirror.edatel.net.co      * epel: mirror.symnds.com      * extras: mirror.edatel.net.co      * rpmfusion-free-updates: mirror.hiwaay.net      * updates: mirror.edatel.net.co     Setting up Install Process     No package qgis available.      seems just with centos this is complicated! If you can help me I really apreciate it. Greetings from Ecuador. sorry my English


title: How to add a layer file to an ArcGIS map document programmatically?

text: I want to create a feature layer from a layer (.lyr) file and add it to my ArcGIS map document programmatically. I am using C# and ArcGIS. I have a layer file and a shapefile.


title: Cursors and Field calculation - Python 2.5 - ArcGis 9.3

text: I hope my question is not redundant. I wrote a script to Update a table using two imbricate cursors. The goal was 1) to read a records, update some of its values 2) Make a selection based on this record (e.g. closest neighbors) 3) Update the neighbors I have first tried using two imbricate update cursors like the following:               rows = gp.UpdateCursor(Infile)     row = rows.Next()      while row:         # Read InFile attribute         val = row.GetValue(Attribute)         #  Update some attributes         val = row.SetValue(Field, function(val))         # Select Neighbors         gp. gp.GANeighborhoodSelection(Infile, Layer, Condition related to val)         //.....//         # Update Neighbors         urows = gp.UpdateCursor(Infile)         urow = urows.Next()          while urow:             #  Update some attributes             val = urow.SetValue(Field, function(val))             urows.UpdateRow(urow)             urow = urows.Next()          del urow, urows         //.....//         row.UpdateRow(row)         row = rows.Next()         //.....//      Using such a code, the second update cursor was calculating correctly (i printed some intermediate results) but the calculation was not applied to the table (ie. not physical updation). I modified the code by replacing the second update cursor by a Select by attributes followed by a calculate field. Again, the calculations were not applied to the table. I think there is a lock problem somewhere but I did not found how to solve the problem. Finally, I replaced my first UpdateCursor by a SearchCursor and then used an UpdateCursor based on a condition in order to reduce the number of record processed. The code look like this:               rows = gp.SearchCursor(Infile)     row = rows.Next()      while row:         # Read InFile attribute         val = row.GetValue(Attribute)         #  Update some attributes         val = row.SetValue(Field, function(val))         # Select Neighbors         gp. gp.GANeighborhoodSelection(Infile, Layer, Condition related to val)         //.....//         # Update Neighbors         urows = gp.UpdateCursor(Infile, Condition based on val)         urow = urows.Next()          while urow:             #  Update some attributes             val = urow.SetValue(Field, function(val))             urows.UpdateRow(urow)             urow = urows.Next()          del urow, urows         //.....//         row.UpdateRow(row)         row = rows.Next()         //.....//      Using such a structure, all is working fine. However, calculation is longer (around 5 sec. for 1000 records). Do you have any idea 1) why using 2 imbricate UpdateCursor is not working and 2) how to use select by attributes and calculate field within a cursor to fasten the calculation? Thanks a lot Cedric


title: Python script/Model to populate cross street names at intersections

text: Has anyone created a Python version/model of this VBA script from ArcScripts which populates the `to` and `from` street names at street intersections? A logical workflow is outlined quite nicely in this ESRI thread, but it requires ArcInfo, and I would like to know if there is another way to do it. The end result would be, for example, if there are lines intersecting at First Street and Third Street, and First Street and Main Street, the record for First Street would have `to = Third Street` and `from = Main Street` (the order does not matter). Using `Select By Location` to select connected roads seems like it would work, and could even possibly replace the need to create points in the aforementioned workflow (looping over each street, writing to separate fields the streets it touches based on the output of the select by location, then extracting the two street names which are different). Does anyone have any other ideas?


title: How to combine rows in an attribute table

text: I'm fairly new to GIS and could use some help with an issue I've run across. I have an attribute table with three columns "FID" "Shape" and "Class" All records have the same shape (polygon). Each record has its own FID. I have three classes, "A", "B", or "C". I have twenty records for Class C and would like to combine them into one record. I have tried doing a dissolve without specific anything in the Dissolve Fields area and the result was a shapefile with all the Classes combined into one, which I don't want. I also tried doing a dissolve while specifying Class in the Dissolve Fields area. This resulted in a shapefile with the same twenty records for Class C. How do I get those twenty polygons into one record? Thanks in advance for any advice!


title: How to improve drawn shapes in Quantum-GIS?

text: I have a polygon-shape in qgis-1.7.0 and want to fix overlays and gaps between the edges of adjacent polygons. See image below. ![enter image description here](http://i.stack.imgur.com/laIoq.png) Is there any automated way to do this in quantum-gis? Or any other F/OSS that can do things like that? Any hints appreciated! Thanks!


title: Installing Lecos plugin for QGis 2.0.1 on linux fedora 20

text: I try to install Lecos plugin, which requires python imaging library (pil), but the installation fails with the following: "you need to have the image library pil installed" I installed the python-pillow library instead of the pil library: pil is almost dead and I can't find it in fedora repositories so i suppose it has to be build from source. Pillow is the "new pil" library and using pillow the command "from PIL import ModuleX" does work from the qgis python console, but Lecos plugin installation still fails. Is there a way to get Lecos recognize pillow library, or do I have to install the outdated pil library ? thanks for your help


title: Shifting Polyline Feature Class

text: I need to horizontally shift a Polyline feature class (clip1diss) (just one raw) 360 degrees East (deltaX = 360). It would be the equivalent as to "Move" in an Edit session in ArcMap but I cannot quite find the appropriate Python code to perform the same operation. Any help would be greatly appreciate it. Many thanks


title: postgis create geom from lat long

text: I ran this query successfully, but the column highwayid isn't updated as expected:               update unique_latlongs set highwayid =        (SELECT h.osmid FROM rn.highways h WHERE h.geom &&       ST_Expand(ST_Transform(st_setsrid(st_makepoint(lon, lat),4326), 3414), 50)       ORDER BY ST_Distance(h.geom,        ST_Transform(st_setsrid(st_makepoint(lon, lat),4326), 3414)) limit 1);      What do you think could be wrong in this query? In unique_latlongs, lat and lon are columns. **EDIT** : Perhaps I should explain what I was trying to do: I have lat and long values in the unique_latlongs table. I also have the column highwayid, which I want to update to the id the the closest highway to each respective lat long in unique_latlongs. The highways are store in the rn.highways table, with the h.geom being the geometry value of the highway.


title: Which free web service for presenting travel routes?

text: I have a plenty of GPS logs from my travels in NZ and would like to create some maps also for other people and share them. The logs are both GPX and plain TXT containing Lon/Lat, altitude and date/time, one file per day (but per day using UTC so it is wrong). I need to merge them, correct the UTC time to local time, add some notes and export separate routes. I expect to have multiple routes per day - car transports between various location and then hikes. Have logs for about 20 days... First I was thinking about creating static maps in QGIS but maybe dynamic web maps would be better... Would be perfect if you could select day and zoom to particular route + absolutely ideal if you also could view some notes like altitude or time of the visit for single point. The background map could by Google or OSM. Do you have some experience with such task? The whole "project" is noncommercial (will not get any money for it, unfortunately :-D ) and one-man- show so I do not want to pay for some hosting etc... Any ideas or advices welcomed. Thanks :-)


title: Web Application/Android Application

text: I want to develop a web application/android app which has following functions.   1. Runs OpenStreetMaps   2. Creating Markers   3. Changing colors of the markers   4. Connecting all to a MySQL Database Please let me know how can I proceed. Thanks


title: Geoserver Exception Handling

text: I'm implementing an application that uses GeoServer deployed on apache tomcat. I would like to know if there is a way to handle an error case, such as when GeoServer is hung. For example, I'd like to display a message to user or something like that on client side. I've been told that :               If GeoServer hangs, you will receive no answer. You should set a read        time out for your GeoServer HTTP requests. After the timeout, you can        send back whatever you want.       but since I'm pretty beginner at these stuff, I've no idea how to do that. would anyone please explain me more how to set a readtime out for your GeoServer HTTP requests ?? **EDIT: Can I convert the configuration in proxyhost to message displays to the user ?**


title: How to Intersect between a vector (administrative areas) and a raster layer (slope)?

text: What I've got: 1: A vector-layer with administrative areas of my country 2: A raster-layer with the slope of the terrain of the same country (it is derived from SRTM elevation data with QGIS) What I want: A new vector-layer with the 'flat' land of all administrative areas. How do I achieve this in QGIS? A) How to extract the area below a certain slope (in the raster-layer)? - The option for rule-based display is not available (maybe this is just there for vector-layers). B) How to 'intersect' the flat-land-raster-layer(-mask) with my admin-vector- layer? Update: A) Actually the "Clip to MinMax" with an appropriate set Min- and Max-value (e.g. Min: 10, Max: 100 - or inverse Min: 0, Max: 10.1) does the job. Now I want to use this as a 'clipping-mask' for my vector-layer, but how?


title: Feature edition errors

text: I've created a feature editor, of a puntual feature layer, in a flex 3.1 client. The feature layer is served by a feature service in ArcGIS Server 10.0. When I try to update or delete features (I didn't try creation), I get errors eventhough the changes are made in the database. The errors are like these :               TypeError: Error #1009: Il est impossible d'accéder à la propriété ou à la méthode d'une référence d'objet nul.         at com.esri.ags.components::Editor/saveUnsavedAttributes()[C:\checkout\flex_api3\api\src\com\esri\ags\components\Editor.as:5189]         at com.esri.ags.components::Editor/attributeInspector_saveFeatureHandler()[C:\checkout\flex_api3\api\src\com\esri\ags\components\Editor.as:2674]         at flash.events::EventDispatcher/dispatchEventFunction()         at flash.events::EventDispatcher/dispatchEvent()         at mx.core::UIComponent/dispatchEvent()[E:\dev\4.y\frameworks\projects\framework\src\mx\core\UIComponent.as:13152]         at com.esri.ags.components::AttributeInspector/dispatchSaveFeatureEvent()[C:\checkout\flex_api3\api\src\com\esri\ags\components\AttributeInspector.as:1030]         at Function/http://adobe.com/AS3/2006/builtin::apply()         at mx.core::UIComponent/callLaterDispatcher2()[E:\dev\4.y\frameworks\projects\framework\src\mx\core\UIComponent.as:12232]         at mx.core::UIComponent/callLaterDispatcher()[E:\dev\4.y\frameworks\projects\framework\src\mx\core\UIComponent.as:12170]               TypeError: Error #1009: Il est impossible d'accéder à la propriété ou à la méthode d'une référence d'objet nul.         at com.esri.ags.components::Editor/featureLayer_editsCompleteHandler()[C:\checkout\flex_api3\api\src\com\esri\ags\components\Editor.as:1491]         at flash.events::EventDispatcher/dispatchEventFunction()         at flash.events::EventDispatcher/dispatchEvent()         at mx.core::UIComponent/dispatchEvent()[E:\dev\4.y\frameworks\projects\framework\src\mx\core\UIComponent.as:13152]         at com.esri.ags.layers::FeatureLayer/http://www.esri.com/2008/ags/internal::editHandler()[C:\checkout\flex_api3\api\src\com\esri\ags\layers\FeatureLayer.as:2638]         at mx.rpc::AsyncResponder/result()[E:\dev\4.y\frameworks\projects\rpc\src\mx\rpc\AsyncResponder.as:95]         at com.esri.ags.tasks::FeatureLayerTask/handleApplyEdits()[C:\checkout\flex_api3\api\src\com\esri\ags\tasks\FeatureLayerTask.as:311]         at Function/http://adobe.com/AS3/2006/builtin::call()         at com.esri.ags.tasks::BaseTask/handleResultEvent()[C:\checkout\flex_api3\api\src\com\esri\ags\tasks\BaseTask.as:729]         at mx.rpc::AsyncResponder/result()[E:\dev\4.y\frameworks\projects\rpc\src\mx\rpc\AsyncResponder.as:95]         at mx.rpc::AsyncToken/http://www.adobe.com/2006/flex/mx/internal::applyResult()[E:\dev\4.y\frameworks\projects\rpc\src\mx\rpc\AsyncToken.as:239]         at mx.rpc.events::ResultEvent/http://www.adobe.com/2006/flex/mx/internal::callTokenResponders()[E:\dev\4.y\frameworks\projects\rpc\src\mx\rpc\events\ResultEvent.as:207]         at HTTPOperation/http://www.adobe.com/2006/flex/mx/internal::dispatchRpcEvent()[E:\dev\4.y\frameworks\projects\rpc\src\mx\rpc\http\HTTPService.as:991]         at mx.rpc::AbstractInvoker/http://www.adobe.com/2006/flex/mx/internal::resultHandler()[E:\dev\4.y\frameworks\projects\rpc\src\mx\rpc\AbstractInvoker.as:318]         at mx.rpc::Responder/result()[E:\dev\4.y\frameworks\projects\rpc\src\mx\rpc\Responder.as:56]         at mx.rpc::AsyncRequest/acknowledge()[E:\dev\4.y\frameworks\projects\rpc\src\mx\rpc\AsyncRequest.as:84]         at DirectHTTPMessageResponder/completeHandler()[E:\dev\4.y\frameworks\projects\rpc\src\mx\messaging\channels\DirectHTTPChannel.as:451]         at flash.events::EventDispatcher/dispatchEventFunction()         at flash.events::EventDispatcher/dispatchEvent()         at flash.net::URLLoader/onComplete()[/CODE]      In the code I have declared the editor inside the along with a geometry service:               <esri:Editor id="mainEditor" map="{mainMap}" geometryService="{geometryService}" />      And I assigned the following method to 'initialize' attribute of the application:                protected function application_initializeHandler(event:FlexEvent):void                 {                     mainEditor.featureLayers = [arrets];                      }      where "arrets" is the name of the feature layer I want to edit. Do you have any idea of why the errors appear? Regards.


title: How to enable "snapping" in Quantum-GIS while drawing polygons?

text: I tried to draw polygons in qgis-1.7.0 and I somehow can't find or failed to find the "snapping" option. I'm used to ArcGIS-10.0 where you have some snapping options, like placing points of polygons at points/edges/shapes/etc. Is this also possible with qgis? And if yes, how to activate it? I've tried to figure out all the editing options, but couldn't find any snapping or similar. Any hints appreciated! Thanks!


title: Can distance be calculated to a destination feature based on an attribute in the source?

text: All, Is it possible to specify which destination point to calculate distance to based on an attribute in the source? STDistance will give me the distance each student (point) is to their closest school (point). When I pull a list of students based on their boundary school number (the school they should go to based on their proximity to their house), I also get back their choice school number (the school they actually go to). I would like to calculate the distance each student is from their choice school. I'm using SQL Server 2012, hence the STDistance function (rather than ST_Distance in PostGIS) Any thoughts appreciated! -m


title: Overlapping buffers - Doublecount points that fall within 2 or more buffers

text: I want to analyze crime around certain types of stores in a city. I made buffers around the stores and I need to a) select and extract crimes that occurred within those buffers, and b) join the two shape files (buffers and crimes) so that for every crime I also have information on the store it is close to (e.g. type of store, opening date). Here's my problem: When two buffers overlap and a crime falls within both of them, I need to doublecount that crime and assign it to both buffers (and both stores). Is there a way to do this in ArcMap? Thank you, Giulia


title: Rendering 3D timezones KML on a 2D map

text: I'm trying to render a KML layer (with timezones) in Google Maps API v3. The KML layer works fine in 3D (in Google Earth), but when I render it in 2D, the timezone lines that meet at the North Pole are spread out in a really weird way: ![Google Maps rendering](http://i.imgur.com/9v9VQ.png) Here is the correct rendering in 3D: ![Google Earth rendering](http://i.imgur.com/TsTNu.png) How do I get fix that weird spread?


title: How to merge raster quadrangle tiles in qgis?

text: I've downloaded some dem tiles from here http://www.granit.unh.edu/data/search?dset=dem/dem174, which I'd like to merge into a single smooth digital elevation model usinq QGIS. So far I've tried to use the raster merge function (gdal_merge.py) with default options. The merge is successful, but null value bands are introduced between the original dem extents that are actually larger than I would have expected from viewing the tiles separately. How do I get rid of these gaps?


title: 10 GB Raster Aerial Image in Quantum and POSTGIS

text: I have a problem... I have been successful in uploading the raster in postgis but when I access it through Qgis. it does not open even after several hours. I have 10GB aerial image raster and everytime i try to open it through QGIS it does not open even after many hours and QGIS crashes... why is this happening...?? is it really due to the file size..?? Regards, Omer


I want to do time based mapping on openstreetmap data in the Kathmandu, Nepal area. I think i have two options   1. Using OpenStreetMap Change files (OSC)   2. Using OpenStreetmap History files (OSH) I have found js libraries for reading OSC files. Are there any js libraries for reading OSH data?


title: Do I have to convert a line shapefile to points to store it in another database?

text: This is the surprisingly the first time I've come across this. If I wanted to export a line shapefile from ArcGIS to another database (say Access) would I first need to convert the vertices to points and add the x y columns? To then reuse the data in a GIS I would need to convert back to lines. I feel sure I must be missing something.


title: How to check WFS error

text: I'm adding a layer to an OpenLayers Map which includes data from GeoServer retrieved using WFS. The layer is created like following:               var saveStrategy = new OpenLayers.Strategy.Save();     var wfs = new OpenLayers.Layer.Vector("Editable Features", {         strategies: [new OpenLayers.Strategy.BBOX(), saveStrategy],         projection: new OpenLayers.Projection("EPSG:26713"),         protocol: new OpenLayers.Protocol.WFS({             version: "1.1.0",             url: "http://localhost/geodemo/geoserver/wfs",             featureType: "LayerName",             srsName: "EPSG:26713",                 featureNS: "http://www.openplans.org/MyNS",             geometryName: "the_geom",                                 })     });       When sending WFS messages to GeoServer, the server could send errors (formatated as XML). How it is possible to be aware from these errors? Thanks.


title: OverlappingMarkerSpiderfier show which markers are in a 'spiderfy cluster'?

text: I have a google map with a bunch of markers on it. Some of those markers have the same lat/lon as other markers, so sit on top of each other. I'm using the oms library to allow for the markers to be spiderfied out so each marker can be clicked. All working great so far. However the only way you can tell if there's multiple markers is by clicking on the markers, which is a problem for my application. **Is there a way to indicate which markers are grouped into 'spiderfy' clusters?** I'm also using the MarkerClustererPlus library to handle clusters. It could be possible to use the clusterer library to provide a count and then 'on click' spiderify the markers but I couldn't figure out how to do that. Thanks in advance for any help.


title: Rendering PyQGIS objects in MapCanvas

text: I'm quite new to PyQGIS and have what is probably a pretty basic question, but I haven't been able to pick it up from the documentation. I have a `QgsVectorLayer` object from a PostGIS server, and I want to render it in the Map Canvas. How do I go from vector layer object to rendered map? Thanks!


title: How can you prevent ogr2ogr from truncating trailing zeros when setting coordinate_precision=0 and saving to GeoJSON?

text: This weekend I started using ogr2ogr and discovered that it's a great tool for converting from one spatial reference system to another. I used it to convert a shapefile to GeoJSON, from WGS84 to a NAD83 stateplane, and wanted decimals truncated, but I discovered that its "smart truncation" feature then truncated the trailing zeros on the resulting integers (e.g., 1100000 was written as 11). I searched the web for a while, but wasn't able to find a command-line argument that would avoid this issue. Below is the full command I was running. My short-term solution was to set the precision to 1 and then use a regex on the resulting file to truncate decimals.               ogr2ogr -f "GeoJSON" CTABusStops.json -s_srs EPSG:4326 -t_srs EPSG:102671 -select     OBJECTID,STOP_ID,STREET,CROSS_ST,DIR,POS,ROUTESSTPG,PUBLIC_NAM -where STATUS=1 -lco     coordinate_precision=0 CTA_BusStops.shp


title: create grid cells of fixed dimension around a point acting as a centroid

text: I've been trying to solve a problem for the last few days but not having much luck. I'm hoping someone here can point me in the right direction. I'm new to ArcGIS so I hope my explanation makes sense. Here's my problem. I have a layer of points with x,y co-ordinates. They are laid out in a mecrator projection. What I need to do is create another layer with a grid. Each grid cell needs to be 2 degrees high, by 2 degrees wide, with the point acting as a centroid (so the boundaries are at a distance of 1 degree above the point, 1 degree below, 1 degree left and 1 degree right of the point). The grid cells cannot overlap. Because of the mecrator projection, I would expect the height of each cell (latitude) to remain the same, but the width (longitude) to expand the further away from the equator they are. I've tried the thiessen polygon tool, creating buffers, the fishnet, and the minimum bounding geometry tool but its not quite what I'm after. Any ideas? Any help is greatly appreciated! Thanks very much PS: I've popped a (badly drawn) image up on to G+ of what I want. See here. Figure 1 is what I have, and Figure 2 is what i need to create ![enter image description here](http://i.stack.imgur.com/Y8YEl.jpg)


title: How to get custom colormap onto 3D NVIZ in QGIS GRASS

text: I am trying to create a 3D version of my 2D raster using QGIS GRASS NVIZ. I have been following these steps: http://linfiniti.com/2010/12/3d-visualisation-and-dem-creation-in-qgis-with- the-grass-plugin/ I have no problems creating the 3D model, but my colors always get lost. This is frustrating because the second option on the NVIZ module asks for a raster to use for color. I've tried multiple times to get NVIZ to create the 3D model with the color of the raster indicated and I always get the Pseudocolor or grayscale colormap. The link provided in the above directions (http://linfiniti.com/2010/12/a-workflow-for-creating-beautiful-relief-shaded- dems-using-gdal/) claims to explain how to map colors, but does so only through command line procedures. I am not yet familiar enough with GRASS command line to take that route and meet my deadline. This GISSE question did not really explain how to do it through the NVIZ module: How to change the raster color range in GRASS NVIZ? Any suggestions would be much appreciated. -mike


title: kml network link styling

text: I have a kml network link (parent) that loads a second kml file (child) that contains a set of polygons. Currently the style of the polygons is set to a url within the child kml file. I would like to be able to modify the style of the polygons at the level of the network link, without having to change the childs xml. Is this possible?


title: Computer vision/Image processing degrees

text: I just want to ask. Where do you recommend someone to take a "Computer vision/Image processing" related degree ONLINE? Thanks.


title: Protect our WMS map tiles to only accessible from our site

text: We are using geoserver (2.3) to serve WMS map tiles generated from mapping data we licenced. We use leaflet on the client side to show the map (part of a ruby on rails site running on heroku). Because of the licence of the mapping data, we should not allow anybody to use these map tiles, it should be only accessible by our users when they are using the map on our website. Is there any way to avoid somebody just taking the WMS URL from our javascript code and using it on another site? Or bulk downloading all the map tiles? We can configure the geoserver to require username/password or certificate, but then we would need to expose it to the client side. Thanks!


title: Basic proj4 conversion UTM grid -> longlat and back

text: I'm a GIS novice, and am struggling to understand how to drive proj4 to accomplish what seems like a simple thing. I've googled for a couple of days, but everything I find seems to presuppose quite advanced knowledge, and leaves many things unsaid. Stack overflow couldn't clear it up for me, either.. I have a conversion between UTM easting/northing and lat/long to do in both directions. Once I get this working, I'll add some different projections/datums. I'm working on my recently acquired knowledge/assumptions:   1. This conversion will require a datum translation, because WGS84 (standard datum for UTM) has it's prime meridian approximately 100m east of Greenwich (where longitude is zero).   2. I don't need to worry about ellipsoids, because the lat/long are _geographic_ coordinates, rather than projected ones.   3. I can either start the conversions using one string (as used in the command-line instantiation), or can pre-assemble a source and destination object, and call `pj_fwd(data, ref)` directly. Another issue is that if I call the code directly, while I've found the `projUV` datatype - I can't find the corresponding UTM version. Could someone _please_ get me started with the format of the string(s) of either method required? Say conversion from zone 56 499451mE 6960921mS to lat/long as an example? Many, many thanks.


title: How to trim strings in Field Calculator?

text: I am currently working on a County plat book and am in the process of prepping the "Owner_Nm" field that will serve as my annotation layer. I am trying to whittle down the owner names, based on parcel size, to either full name (easily done) to first initial + full last name or just initials. The format of the names is currently something like this "John H Smith" or "John H Smith & Lucy L Smith" for example. I know next to nothing about python in field calculator so I am hoping to get some help from this community. INRE: how to write my python code in field calculator to return, dependent on parcel size, either (using the above examples) "J H Smith" or "J H S" or "J H Smith & L L Smith" or "J H S & L L S". I have nothing to offer as to the code I've tried as it has mostly returned gibberish....Thanks in advance.