title: MapQuest License

text: I read the license of Geodata provider (facebook, foursquare...) but I don't understand what it means: > LICENSE FROM YOU TO MAPQUEST. If you **upload** any data, feedback, ideas, > suggestions, content, points of interest (including any points of interest > that include Trademarks) or other material to MapQuest (collectively “Your > Content”), you **hereby grant MapQuest a perpetual, worldwide, non- > exclusive, royalty-free license to access, archive, reproduce, publicly > display, translate, modify** the format or the display of, distribute, > transmit, stream, cache, overlay, seam, perform, sublicense, and otherwise > use Your Content with or without attribution and without financial > obligation, in whole or in part, via any method for any purpose. MapQuest > makes no assertion of ownership over Your Content, and you retain all > intellectual property rights to Your Content, subject to the license you > grant to MapQuest above. For example, I would like to use their data and load it into my geodatabase. Is that allowed?


title: How to join averaged precipitation values to each municipality

text: I have precipitation data that I would like to average over each municipal unit in a boundary layer. First, how do I average the rainfall spatially by each administrative unit? Second, the rainfall values are not unique to each administrative unit, and so I am not sure how to join them to the attributes table of the admin boundary layer. Although they will be unique once they are averaged, in the sense that there is one averaged value per administrative unit. If this is true, which variable do I merge on? Do I need to create something new? I am using the end result (an average rainfall value for each municipal unit) in STATA, hence the need to export the attribute table. The program I'm using is ArcMap. I did something like this years ago but cannot remember...any help would be greatly appreciated!


title: Sync tables option not available in local install of CartoDB

text: I've got a production version of Cartodb running locally, but when I try and create a table based on a spreadsheet hosted on dropbox I dont get the option to keep the data in sync, instead I get upgrade your account. What do I need to do to resolve this? Thanks


title: Putting multiple lines of Python into ArcGIS 10's Field Calculator

text: I've gotten some incredibly valuable help here on this already, much Thanks. Entering these lines of Python one at a time works like a charm.... Just need one more seemingly simply issue solved... How do we place **multiple** lines of Python code into ArcGIS's Field Calculator without producing **Error 000539 or syntax error**? I've tried several different syntaxes with colons and various spacings / returns .... screen shot: ![enter image description here](http://i.stack.imgur.com/lY7RA.jpg) multiple lines of Python code here:               '1201-LT 210A' if !sc2! in (12013,11999,11998,12016,12015,12004,12012,12011,12001,12002,11997,12017,12009,12003) else !March_Proj!          '1201-LT 210B' if !sc2! in (12074,12076,12078,12072) else !March_Proj!          '1201-BO' if !sc2! in (20052,20053,20044,20045,20039,20050,20051,24157,24158,22927,24783,24785,24784,24782,24035,22924,23923,24154,22528,21912,23164) else !March_Proj!          '1202-LT 21F' if !sc2! in (1067,1066,1078,1060,1052,1075,1068,1051,1079,1062,1070,,1071) else !March_Proj!


title: Which projection casts rays from a point on the surface of the globe to a cylinder?

text: What is the name of a map projection that casts rays from a point on the surface of the globe to a cylinder? Some people who make sundials put a map of Earth on the sundial. I want to use the "right" map projection such that, when the nodus casts a shadow on a particular city on the map, the sun is directly overhead that city on the real Earth. If the sundial is in the form of (part of) a cylinder, and the nodus fixed to a point on the axis of the cylinder, then such a map uses the cylindric perspective projection. If the sundial is entirely composed of flat surfaces, then such a map uses a gnomonic projection on each surface. A few sundials are in the form of (part of) a cylinder, and the nodus is a small notch or hole in the curved surface of the cylinder. Carl Sabanski calls this a "Cylinder Sundial: Type 1". Is there a name for the kind of map projection I want to use in this sundial? In the form of an analogy question: gnomonic projection : azimuthal conformal projection :: cylindric perspective projection : ___ _? **Edit:** Oops. My description seems to be a mishmash of 2 different projections. For lack of better names, for now I'm going to call them the "point-on-globe-in-cylinder projection" and the "Type 1 cylinder sundial projection". I hope that I will soon learn some other, less awkward name for each projection. After posting the original question, I realized that the "point-on-globe-in- cylinder projection" is _not_ the one I want to put on my "Type 1 cylinder sundial". The "point-on-globe-in-cylinder projection" involves a globe inscribed in a cylinder, where both of them have radius R, like most cylindrical projections. Like the azimuthal conformal projection, there is very low distortion around one special center point on the map. Like the azimuthal conformal projection, rays start at the antipode of that center point, then hit some city on that globe, travel a bit further and hit the paper where that city is mapped. Like most cylindrical projections, since the globe touches a circumference of the cylinder along some great circle, the map is pretty accurate at points near that great circle. With a very long cylinder, almost all the globe can be mapped. The "Type 1 cylinder sundial projection" is the projection I want to place on my "Type 1 cylinder sundial". The globe has radius R, while the cylinder has radius R/2. The globe is positioned so the geometric center of the earth is at the nodus hole on the surface of the cylinder. The point on the surface of the cylinder diametrically opposite the nodus is a special central point. The surface of the cylinder is tangent to the surface of the globe (only) at that central point. Along the straight line from that central point along the length of the cylinder, it's approximately a gnomonic projection -- rays start from the center of the globe, then hit a city on the globe, then travel a bit further and hit the paper where that city is mapped. Along the circumference from that central point around the cylinder to the nodus hole, rays start from the center of the globe, then hit the paper cylinder where a city is mapped, and then hit that city on the globe. With a very long cylinder, almost half the globe can be mapped, the hemisphere around the central point. Since there is a small hole punched in the surface of the cylinder to form the nodus, rays from the center of the nodus to the antipode of the central point (and the hemisphere around that antipode) never strike the cylinder, and so are not mapped anywhere on the cylinder. Is there a better name for what I'm calling the "point-on-globe-in-cylinder projection"? Is there a better name for what I'm calling the "Type 1 cylinder sundial projection"? Should I split this question up into 2 different questions, each one asking about 1 of these 2 projections?


title: VBA script for Incremental labeling in Field Calculator?

text: I have a shape file with a bunch of pipes in it. I would like to be able to label each pipe with "Pipe - X". X being the number in the row that the pipe falls on (Pipe - 1, Pipe - 2, Pipe - 3, etc). I've tried using a for loop VBA Script for this but it doesn't work. The VBA script is as follows: For counter = 1 To 192 Y = "Pipe - " & counter Next counter Pipe_ID = Y My result is "Pipe - 192" Any Ideas?


title: How can I specify a PROJ.4 projection with the north pointing *down*?

text: I would like to create a world map "upside down", with the south on top (in Mapnik). Can I take an existing projection string, e.g. Robinson projection               +proj=robin +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs      and flip/mirror it so the north points down?


title: How to use any ArcMap tool from a python script?

text: I'm trying to develop a tool that uses some of arcmap default tools like the `Sketch Tool` or `Trace Tool`. Is it possible? Let me explain a little more, I need to draw a feature, ask for user input, and save the feature + data to the shape file, can it be done using python?


title: Is it possible to save PostGIS connection string in OGR add-in to QGIS?

text: In QGIS I've saved a couple of PostGIS connections for adding data. This works fine. I've been unable to save the connections in the OGR layer converter add- in though. Has anyone found a way to do this so I don't have to type it every time?


title: Creating Raster with values based on function output

text: I have a function that calculates a price based on the input slope and distance. I want to write the price to a raster as the rastervalue. How do I do that? OpenSource and ArcMap solutions would work.               slopeRaster = "slope.tif"     emptyRaster = "emptyraster.tif" # How do I create an empty raster?     road = "road.shp"          for cell in emptyraster:         # get slope from sloperaster at cell location         ...         slope = ...              # get distance to nearest road from center of cell         ...         distance = ...              # calculate price for cell         price = pricefunc(slope, distance)              # write price to cell as value  # How do I write a value to a raster


title: Is there a way to populate a spreadsheet of city names with their latitudes and longitudes from Google Maps or some other service?

text: I have a long list of cities in the United States, and would like to get the coordinates for each city without looking up each one individually. Is there a way to do this?


title: ArcObjects diagram/object model?

text: Is there an existing object model diagram for ArcObjects? Something that can be printed out as a large poster.


title: Where is Web Applications in ArcGIS server 10.1?

text: I'm new in using ArcGIS server 10.1 . I used ArcGIS server 9.3,9.3.1 and 10 several years.now i want to use ArcGIS server 10.1.When I install ArcGIS server 10.1, I coudln't find Web Applications tab like ArcGIS 10 or later . In ArcGIS server 10 web applications and web services installed separately but In ArcGIS server 10.1 i just setup "ArcGIS For Server". I could create services but not Web Applications.The questions are that Where is Web Appications in ArcGIS server 10.1 ? How can i create a web application in ArcGIS 10.1 using wizard ? Thanks for Advance


title: Best way for rendering geotools in web service

text: I'm using geotools in my web service project. I always thought geotools is somehow compatible with openlayers, but now when it actually came to implementing this functionality, i can't find even one example. Any other ideas, tools to do it? I've read that geoserver is using openlayers with geotools, but as i said i can't find any example,documentation.


title: Loading custom dojo and Esri

text: We have to develop an application which will have lot of rich ui along with a map. For the map, I am using the arcgis javascript api which includes dojo. For UI components other than the map, I want to use a copy of dojo which I will host locally. How can I load both of these? I read this blog esri dojo, but this works with api 1.6, and I am using 3.6.


title: Access to SpatiaLite .dumpshp via Python?

text: I'm trying to interact with a SpatiaLite database via Python on my Windows machine. I've managed to connect to the database and load the SpatiaLite extension, which means that I can pass SQL queries in from my Python code e.g:               from pysqlite2 import dbapi2 as sqlite     myPath = r"C:\SpatiaLite\test-2.3.sqlite"     conn = sqlite.connect(myPath)     conn.enable_load_extension(True)     curs = conn.cursor()     curs.execute("select load_extension('libspatialite-1.dll')")         curs.execute("""SELECT name, peoples, AsText(Geometry) from Towns where                     peoples > 350000 order by peoples DESC""")     # Print the selected records     for row in curs:         print row      So far so good. I'd now like to know how to export a table as a shapefile. Using the command prompt in spatialite.exe I can do this using `.dumpshp`, but I can't figure out how to access this command from Python. Any ideas, please? I was hoping for something like this:               curs.execute("select dumpshp('Towns Geometry shape_towns CP1252 POINT')")      but perhaps it's more complicated than that? Thanks very much!


title: Add Raster To Mosaic Dataset: Could not recommend a data source crawler for the specified input

text: I'm trying to add rasters (TIFF) to a Mosaic Dataset after adding some rasters, the process fails with the message. ERROR 999999: Error executing function Could not recommend a data source crawler for the the specified input. The data source might be unnavigable or unrecognised. Failed to execute (AddRastersToMosaicDataset) What does this message mean and how do I fix the problem? I can't find anything different about the TIFF which failed compared with any other. I am using ArcCatalog 10.1 on Windows 10.1 x64 with the 64-Bit Geoprocessing.


title: Point Cluster Layer not defined

text: I am trying to do a point cluster layer based on the JSON objects I obtained from database. Here is my JavaScript to plot a point cluster layer:               function addClusters() {     $.ajax({         url: "index.aspx/getBusCommuter",         type: "POST",         data: "",         contentType: "application/json; charset=utf-8",         dataType: "json",         success: function (data) {             var parsed = JSON.parse(data.d);             $.each(parsed, function (i, jsondata) {                 var coordXicon = jsondata.BusStopX;                 var coordYicon = jsondata.BusStopY;                 var commuterAmt = jsondata.CommuterAmt;                      var latlng = new esri.geometry.Point({ "x": coordXicon, "y": coordYicon, "spatialReference": { "wkid": 4326 } });                      // cluster layer that uses OpenLayers style clustering                 clusterLayer = new ClusterLayer({                     "data": commuterAmt,                     "distance": 100,                     "id": "clusters",                     "labelColor": "#fff",                     "labelOffset": 10,                     "resolution": map.extent.getWidth() / map.width,                     "singleColor": "#888"                 });                 var defaultSym = new SimpleMarkerSymbol().setSize(4);                 var renderer = new ClassBreaksRenderer(defaultSym, "clusterCount");                      var picBaseUrl = "http://static.arcgis.com/images/Symbols/Shapes/";                 var blue = new PictureMarkerSymbol(picBaseUrl + "BluePin1LargeB.png", 32, 32).setOffset(0, 15);                 var green = new PictureMarkerSymbol(picBaseUrl + "GreenPin1LargeB.png", 64, 64).setOffset(0, 15);                 var red = new PictureMarkerSymbol(picBaseUrl + "RedPin1LargeB.png", 72, 72).setOffset(0, 15);                 renderer.addBreak(0, 2, blue);                 renderer.addBreak(2, 200, green);                 renderer.addBreak(200, 1001, red);                      clusterLayer.setRenderer(renderer);                 map.addLayer(clusterLayer);             });         },         error: function (request, state, errors) {         }     });     }      However, when I try to run it, it told me an error message which is clusterLayer is not defined. I wonder which part I missed and am I doing in the correct way. Also, I wonder is it possible/correct to set the commuterAmt I obtained to data so that for each point on the map will be attached with the correct amount? I get the reference from: ArcGIS Documentation Thanks in advance.


title: How to save currently opened mxd and changes using ArcPy and Python?

text: Here is what I have so far...               import arcpy          import arcpy.mapping as map          mxd = map.MapDocument()          mxd.save()      And yes I know that map.MapDocument requires an argument, but I want it to automatically select the currently open mxd, and overwrite it. If I can't get it to select the currently open mxd I can use:               > import arcpy     >      > import arcpy.mapping as map     >      > mxd = map.MapDocument(C:\GIS\Untitled.mxd)     >      > mxd.save()      But I would still like it to overwrite the mxd with the changes I just made to it in arcmap. Think of it like the save button except scripted. Any help is greatly appreciated.


title: Raster format to read with python

text: I currently have a DEM raster stored in an ESRI geodatabase. I've been asked to create a purely python (e.g., no arcpy functions) program that works with the values. Therefore, I need to convert the raster into something that can be read by python as an array. What file format would that be? (Alternatively, is this a terrible idea and should I argue for sticking with arcpy functions?)


title: ST_MakeEnvelope returning too many geos

text: I am using the following query in my db:               SELECT bg_id, ST_AsGeoJSON(the_geom)     FROM bg     WHERE bg.the_geom && ST_MakeEnvelope(xxx, xxx, xxx, xxx);      It seems to execute alright but when I draw out the geos on my map (I'm using Leaflet for this) it includes a bunch of geos that are not within the bounds I provided. For a little more detail as to what exactly I'm trying to accomplish... I have a map on a webpage. As the user navigates throughout the map the bounds of the map are sent back to the db and then the db should send back geos for only what is within the current view. This seems to only be working if the map is zoomed in very close. If I zoom out at all it begins to include lots of geos that I am not looking for. I would only like to include geos that are ENTIRELY within the view. Thanks.


title: Help with Python and adding a grouplayer to arc, renaming it from a folder name, then adding layers to it from that folder

text: I am trying to use os.walk to go through a directory tree, pull out all the .shp files in it, create a grouplayer in the mxd, rename the grouplayer the folder name, then add the layers from that folder to the group. This is because I have a lot of folders with files in them that represent geologic formation and they don't mean anything once seperated from the name of the formation. From what I read you can't just add a blank group layer in an mxd from python without first creating a blank one and adding that. The problem starts at the for group_name in rename_group_layer loop. It doesn't even make it through to the print group_name test. Basically it just falls out of the loop from what I can tell. Then I need to figure out how to add the layers from the folder into the renamed group layer. I have two lines commented out that I think are a start, but I haven't gotten it to go through the renaming loop yet. It will rename the first "New Group Layer" if I put that line above the loop to the correct folder name. I am pretty new to python so any help you can give would be greatly appreciated. Thanks in advance.               import os     import arcpy          # Set workspace environment to a folder     WS = r'c:\test_define\Appalachian Basin'     arcpy.env.workspace = WS          mxd = arcpy.mapping.MapDocument(r"c:\test_define\test_python_add3.mxd")     df = arcpy.mapping.ListDataFrames(mxd, "layers")[0]          print ("#") *80     for (path, dirs, files) in os.walk(WS):         for name in files:             if name.endswith(".shp"):             print path                print "^^^^^^^^^^^^^^^^^^ path variable"                      try:                     layers = arcpy.mapping.ListLayers(mxd)                     for layer in layers:                         if layer.isGroupLayer and layer.name == os.path.basename(path):                             newLayer = arcpy.mapping.Layer(os.path.join(path, name))                             arcpy.mapping.AddLayerToGroup(df, layer, newLayer, "BOTTOM")                         else:                             groupLayer =                       arcpy.mapping.Layer(r"c:\test_define\empty_group_layer.lyr")                               arcpy.mapping.AddLayer(df, groupLayer, "BOTTOM")                                  layers = arcpy.mapping.ListLayers(mxd)                             for layer in layers:                                 if layer.isGroupLayer and layer.name == "New Group Layer":                                     layer.name = os.path.basename(path)                                  newLayer = arcpy.mapping.Layer(os.path.join(path, name))                             arcpy.mapping.AddLayerToGroup(df, layer, newLayer, "BOTTOM")          #mxd.save()               # print messages when the tool runs successfully                 print(arcpy.GetMessages(0))                 #print ("+") *50             except arcpy.ExecuteError:                 print(arcpy.GetMessages(2))                  except Exception as ex:                 print(ex.args[0])      mxd.saveACopy(r"c:\test_define\test.mxd")


title: How to develop a web mapping app to upload, process, and download results?

text: I would like to make a web mapping application where a user can import their own x-y-z data file, then the application applies filters that I write to it, contours the resulting data, then displays the results and exports to common GIS formats. I have medium-level web programming skills (PHP, MySQL, etc.). My question is this: what tools would be the best way to get my end product? Would something like MapScript work? Or do any commercial solutions come to mind? Thanks for any suggestions anyone might have.


title: Why is my simple arcpy script failing? (sets raster cell value to null if below threshold value, ArcGIS 10.1)

text: As mentioned in the title, simple script to set null cell values below three standard deviations beyond the mean:               import arcpy, sys, os          #Accept input and output raster     inRas = sys.argv[1]     outRas = sys.argv[2]          #Pull mean and standard deviation from input raster     meanie = arcpy.GetRasterProperties_management(inRas, "MEAN")     meanres = meanie.getOutput(0)     meanfloat = float(meanres)          stdev = arcpy.GetRasterProperties_management(inRas, "STD")     stdres = stdev.getOutput(0)     stdfloat = float(stdres)          #Calculate threshold value     threshold = meanfloat + (3 * stdfloat)     threstring = str(threshold)          #Create where clause     whereClause = "VALUE < " + threstring          #Test output     arcpy.AddMessage (whereClause)          #Run SetNull     outRas = arcpy.SetNull(inRas, inRas, whereClause)      This results in the following error:               Traceback (most recent call last):     File       "Z:<directory-redacted>\Nullify.py", line 27, in <module>     outRas = arcpy.SetNull(inRas, inRas, whereClause)     AttributeError: 'module' object has no attribute 'SetNull'          Failed to execute (Nullifiy).      If anyone has any ideas, I'd really appreciate the help, thanks so much. -Alex


title: How to update a value in an ArcSde table using ArcMap's VBA

text: First of all, I want to update a table, not a feature class (no geographical information). I tried the following               Public Sub updateInSql(tableName As String, whereClause As String, field As String, value As String)              ' get table         Dim pTable As ITable: Set pTable = getTableFromSQL(tableName) ' this is my function that gets the table object (it works for sure)         If (pTable Is Nothing) Then Exit Sub              Dim pQueryFilter As IQueryFilter: Set pQueryFilter = New QueryFilter         pQueryFilter.whereClause = whereClause         If (whereClause = "") Then Set pQueryFilter = Nothing              Dim pCursor As ICursor: Set pCursor = pTable.Update(pQueryFilter, False)         Dim pRow As IRow: Set pRow = pCursor.NextRow         Do Until pRow Is Nothing             pRow.value(pRow.fields.FindField(field)) = value             pRow.Store             Set pRow = pCursor.NextRow         Loop          End Sub      I get "Automation Error" at "Set pCursor = pTable.Update(pQueryFilter, False)" Why?


title: Need to get the ArcGIS Runtime SDK for WPF Routing example to work with my gpk and mpk

text: I went through the following two examples to get an idea of how to create a custom, local Routing Task This is a walkthrough that takes you step by step through the creation of your first routing geoprocessing package: http://resources.arcgis.com/en/help/runtime- wpf/concepts/index.html#/How_to_author_and_publish_a_geoprocessing_model/0170000000m5000000/. And here is the second part, that completes the picture and shows you how to run it from code: http://resources.arcgis.com/en/help/runtime- wpf/concepts/index.html#/How_to_develop_a_point_to_point_routing_application/0170000000m6000000/ I was able to get it to run using my map package that I created (with my own vector data). However, when it runs and I click the "Solve" button, I can only get the Route graphic to display, that was displayed when I created the gpk from the result. The two points that I click on when running the code are obviously not used by the code to create the resulting Route graphic. I don’t know what I’m doing wrong with this example. Aren’t you supposed to be able to use a gpk file to (in a sense) run that same model, but with different data each time? Thanks, Renee


title: Defining OID causes Query Layer on PostGIS to disappear from ArcMap?

text: I used query layer to load my layer from PostGIS and show it in ArcMap 10, I had two cases;   1. if I defined the OID in the configuration of connection, there was no problem with the attribute table of the layer but my layer disappeared from the map.   2. if I didn't define the OID, then the layer appeared in the map but when I try to open the attribute table of my layers the following error message occurs:  > Error reading OID form table. Reading rows has been stopped. Check that the > datasource is valid. OID mapped column has null value ... in the table was empty.


title: Calculate polygon field based on neigboring polygon attribute

text: I have a vector shape with many different sized polygons each possessing an own class name (for instance "houses", "houses with offices", etc ...) I want to assign a new field to each polygon containing the name of the majority (higher proportion) of adjacent polygons attribute name. Ergo some kind of **polygon neighborhood analysis**. ![enter image description here](http://i.stack.imgur.com/5QtlW.jpg) The query should look to the attribute of each bordering polygon and change another fields value to the name which occurs the most. For instance the beige polygon in the middle of the above image is surrounded by polygons with the attribute "houses" and therefore it should get the attribute "houses". (Best would be if i can somehow display and save the proportion of different attributed polygons). * * * Does anyone have an idea or a tool how to accomplish this task? I am thankful for every partial or full solution. Any good way to solve this problem is appreciated! I intend to use QGIS, but i can also switch to other tools (Arcgis 9, Grass, Saga, R, ...)


title: OpenLayers.Layer.XYZ keep previous tile if zoom with no tile

text: I've god an OpenLayer web with a custom XYZ layer which downloads tiles from the server itself:               OpenLayers.Layer.MOBAC_OSMDROID_ZIP = OpenLayers.Class(               OpenLayers.Layer.XYZ, {                   name: "tiles base",                   transitionEffect: "resize",                   sphericalMercator: true,                   url: '../map/${z}/${x}/${y}.png',                   [...]               });      The funny thing here is that I can use MOBAC to download selected parts of OpenStreetMap and serve them from my website. So far, so good. The problem is: obviously I do not want to download the whole world from OpenStreetMap, but only, for example, zoom levels 0 & 1 for the world, 2-4 for Europe, 5-7 for Spain and so on. Then, when I am zomming in to Spain I get the right tiles. But if I move outside Spain, I just get the damn pink "no-tile" image. I can easily remove such no-image with the .olImageLoadError CSS class... but it still does not show a map. What I would like is: if there is no tile, use the previous tile, scaled. This way you will probably have an overview of where you are when there are no specific tiles for such level. Any idea? Is something like this included in OpenLayers? Any idea to implemente it myself? Since the "resize" effect does not remove the old tiles for a while, maybe keeping them "forever" would work...


title: Do daytime Road Traffic Accidents (RTAs) have same spatial pattern as those of night?

text: With the following set of recorded data:   1. Location of Road Traffic Accident (RTA) along 160km Expressway   2. Date of accident   3. Time of occurrence   4. Causes of the accident etc What spatial analysis tool in ArcGIS 10.1 can be used to show whether the RTA occurred during the day and night have the same spatial pattern or not? i.e in terms of cluster or being dispersed.


title: How to bring georeferenced raster data into MAPublisher?

text: What is the appropriate method to import a georeferenced raster image into MAPublisher? I have been able to import other forms of map data, and created map views and such for them, but I am now interested in importing a raster image with spatial data and retain that data within MAPublisher. Do I need to have some sort of GIS data in the document before I can import the georeferenced raster image? Or is it possible to bring it in on it's own?


title: What are the advantages of using Rails for a GIS/mapping application?

text: I've heard some good things about Rails, but I don't know much about it yet. There are only a few questions about Rails on GIS.SE (and there's not even a Rails tag).   1. Is it worthwhile to learn about Rails, from a GIS professional's perspective? (eg, what advantages does Rails give when building a website containing GIS functionality, compared to not using Rails?)   2. Are there any examples of good GIS/mapping websites built on Rails? (I don't have any specific requirements in mind yet - I just want to know whether to invest time in learning Rails.) Thanks.


title: How can I share my own spatial data on an online map?

text: Note: I am very new in this field! Can I find an open source map that enables me to display an overlay of my own layers? I need to add some text and rectangles for a certain area, but my modification must be on the tile level (500 mt height as example)? I have a big work area; I need to make a new layer that determines every engineer’s works area, to be shown for my customer. I need to provide him an interactive map, that when he zoom in the area, he will find the details when he reach 500 meter height, I need to r3epeat this method for more than one area in UAE country, and this is the reason why I need it to be an interactive map. Example: This is UAE country map: ![enter image description here](http://i.stack.imgur.com/CVjHF.jpg) This is Abu Dhabu emirates map: ![enter image description here](http://i.stack.imgur.com/dUlnK.jpg) This is area map: ![enter image description here](http://i.stack.imgur.com/cJWAm.jpg) I need to put an overlay on them (from the source data of the rectangles and text, which I included in the question), And I need to show them in web tool or any easiest way.


title: How to extracting raster data to multiple polygons?

text: I have a reclassified raster dataset (10 classes) and I want to find out the area of each class contained within multiple (hundreds-to-thousands) polygons. I have all the polygons in the same shapefile and have used 'Extract by Mask' which has given me the raster for all the polygons, but now I want to do this for each individual polygon. I have been selecting each polygon individually and running 'Extract by Mask' which is working but will obviously take forever with 1000's of polygons.


title: Transform all pixels from one projection to another projection under the Matplotlib Basemap

text: Is there a way to transform all pixels from one projection to another projection under the Matplotlib Basemap?


title: If conditional for multiple raster

text: I have 12 raster on NDVI. I want to use if conditional statement. Something like this :               Con ("raster1"=="raster2"=="raster3"=="raster4"=="raster5"=="raster6"=="raster7"=="raster8"=="raster9"=="raster10"=="raster11"=="raster12","raster1",255)      In that statement, I use raster calculator. But, it is error. Does anyone know how to perform this in ArcGIS?


title: QGIS - identifying polygons and distances along the edges of a superset

text: I have two layers of polygons. layer A is a superset of dissolved polygons from my other layer, B. Using QGIS, how can I determine polygons in B, that lie along the edges of A? There would be some polygons that entirely in the central, but I'm not interested in those.


title: GeoServer LDAP Authentication 'Test Connection' succeeds, but login fails

text: I am attempting to use Active Directory for GeoServer authentication. When I click the 'Test Connection' button on the Admin > Authentication > Providers > LDAP settings page, it says "Connection Successful." However, when I log out of Geoserver, and try to log in with the same credentials, I get an "invalid username/password combination" error. My LDAP settings are as follows, where `ADserver`=my Active Directory server, and `domain`=my company domain: Server URL: `ldap://ADserver/dc=domain,dc=com`   TLS: `[Not checked]`   User lookup pattern: `[empty]`   Filter used to lookup user: `(userPrincipalName={0})`   Format used for user login name: `{0}@domain.com`   Use LDAP groups for authorization: `[Not checked]`   User Group Service: `default` And I have selected this Authentication Provider in my Provider Chain. Why does the Test Connection succeed, but actually logging in fails?


title: How to use ogr2ogr to remove features from a shapefile using sql statements (Unable to open datasource `action/North' with the following drivers.)

text: OK, I've spent the obligatory 15-25 minutes on this and haven't gotten anywhere so, here's the command I'm trying to get to work right now:               ogr2ogr -f "ESRI Shapefile" -where "area > 4000" ./filename_w_area_tight.shp filename_w_area.shp      Which is getting this error:               Unable to open datasource `action/North' with the following drivers.     -> ESRI Shapefile     -> MapInfo File     etc      The error is probably some stupid syntactical thing but the general question is how to use ogr2ogr to "prune" a shapefile based on negative selection criteria. I could of course just as easily use `<` and do it the other way. Whatever works is fine. Generally what I'm trying to do is sieve out tiny speck polygons coming in as artifacts from a raster polygonization process. The step prior to this I've added the area column like so:               ogr2ogr filename_w_area.shp input.shp -sql "SELECT *, OGR_GEOM_AREA AS area FROM input”      which works well. The automation here seems appealing because this is a fairly repetitive process and using qgis takes a lot of time and doesn't allow for multiple processes at one time which is what drove me to this ultimately. I'm currently in the process of building a script to automate in ruby. This is currently the last step. Thanks


title: Discontinuous or Interrupted map projections?

text: Do any of the current open source GIS softwares support discontinous projection systems? E.g. sinusoidal, dymaxion, butterfly, etc? If not, are there any affordable commercial ones that do (affordable meaning < $150)? **Upate:** apparently it was a bad idea to lead with "sinusoidal", as that projection also has a single point non-interrupted form. Please note, the key word here is **discontinuous** or **interrupted**. Thanks. ![Cahill's 1909 butterfly map](http://upload.wikimedia.org/wikipedia/commons/thumb/0/06/Cahill_Butterfly_Map.jpg/220px- Cahill_Butterfly_Map.jpg)


title: Draw lines from points

text: Please any body help me for creating lines from points in electric network for instance electric poles are there in point feature with "polename" field like "P01", "P02", "P03" etc. I need a tool that create lines on Target (Feature Class) from P01 to P02 then P02 to P03 in continue.


title: How to change default projection in ArcPad 10?

text: Is there a way to set a default projection in ArcPad 10? The only way I can tell is by creating a quickProject based on a project that contains a shapefile with the same projection, but that's just ridiculous.


title: How can i search over my layers with openlayers?

text: i have my map running over geoserver and openlayers. but i want to add a search box to find places in it. Well not specifically places but directions. The map reads the layers directly over geoserver ( without postgis) but i'm a bit lost with the search thing. How can i implement this feature and what tools are appropriated for it? Now i will explain how the searching process must be: 1.- I have layers with streets, blocks and house numbers. 2.- the user will search by street name or house direction (house number and street name) and the map will show a list of concordances, if the user select one result on the list it will be zoomed to the destination. Very similar to an Arcgis search tools. Any help will be appreciated.


title: How to toggle layer visibility in ArcObjects?

text: ILayer.Visible seems to have no effect - How can I manually manage layer visibility and actually get the map control to update?               ILayer lyr = mapControl.get_Layer(i);      //this works for custom layers that I define but not for Bing_Maps.lyr or ESRI .lyr files that comes with ArcEngine or connections to ArcGIS Online. For composite layers, I also tried iterating through sub layers and setting the visibility to false               lyr.Visible = false;     mapControl.Update();     mapControl.Refresh();     mapControl.ActiveView.Refresh();     mapControl.Invalidate();


title: How determine data type of points in geotiff DTM?

text: I have some DTMs in geotiff files. I need to read them in C# and I've decided to use libtiff for that purpose. After some investigations, I've found that there are tiled tiffs, so I use ReadTile method to get raw points values. The strange thing for me, newbie to GIS technologies, is that one file seems to storage point elevation values as integers, but another one - as floats (4-byte, single precision). That's the result of comparison of values got by my code and or values from *.tif.aux.xml file.   So, my question is - is there any method to determine whether geotiff file stores values as intergers either floats? There is no answer for that in geotiff specs.


title: Scriptable way to merge polylines that join in ArcGIS

text: I have a number of polylines (around 9000), a number of which have one or both ends touching another polyline. I would like to merge these ones together into one polyline - thus reducing the number of polylines and ensuring that each line represents one real-world object (rather than having multiple lines per object). I cannot find a scriptable (preferably through a Python script) way to do this. Is this possible? It would seem to me like a fairly common operation to want to do, but I can't seem to find a built-in function.


title: Floating Image Layer in OpenLayers

text: I'm making a Map Visualization which requires an overlay that shows the light/dark patterns across the planet (like this). I accomplished this by building a simple image layer that loads an image with a cosine wave shaded black on the top half (I'm not worried about seasonal adjustments yet). I can set the extent on the according to the current time to get a map that shows the light patterns in real time. However, I can't figure out how to move the Image Layer without moving the base Layer to show the light/dark overlay in the past or future. My first inclination was to use some sort of move() method, but I couldn't find it in the API. So I tried to adjust the Layer's extent on each change like this:               sunLayer({extent : new OpenLayers.Bounds(newLong, -90, newLong+360, 90)});     sunLayer.redraw();      But nothing happens. I was thinking that maybe I need to build a Vector Layer with just one Feature (the image), and then tie the dimensions of the graphic to the dimensions of the map and move the feature around, but this approach feels wrong to me. Has anyone else done something like this (where you entirely decouple an Image Layer from the base layer)?


title: Insert Javascript code in Popup.FramedCloud?

text: I would like to have a live stream from a web camera in a Popup.FramedCloud. All I need to do is to insert this code in the HTML code parameter for popup:               <script src="http://www.live-events.ro/cam-acces-privat-delay.js.php?id=13"      type="text/javascript">      From my tests this is not working. Please tell me if you tried this with success! The script is correct, you can see it in action here. I tried something more simple like "eval('a=1;alert(a)')" but with no success. I see the code in Firebug, but alert window does not appear. The alternative I think of is to use other object for the popup, an Ext JS object maybe or some kind of reach tooltip library. Thank you!


title: Smoothing raster features into polygon

text: I have raster data representing urbanized areas, which I'd like to trace and convert to a polygon. ![Raster](http://i.stack.imgur.com/53X2r.png) Using ArcMap's Raster to Polygon tool, I'm able to get something close to that. Unsimplified: ![Unsimplified](http://i.stack.imgur.com/24iOv.png) Simplified: ![Simplified](http://i.stack.imgur.com/tPIDU.png) However, you can see that there are many diagonal lines (roads) which create chains of polygons that share a corner. This ups my polygon count significantly - these raster datasets are being processed at the state level. Is there an Arc or GeoTools tool to smooth out these lines and create fewer polygons? It's okay if the result loses some precision. In the end, I'm looking for something similar to what I get with the simplified polygon, just with adjacent polygons joined.


title: Improve database performance for geospatial

text: I have a database with osm data imported with osmosis tool. I want to search for the nearest POIs from a **given point**. For this purpose, I perform this query:               select id from nodes     where geom='0101000020E6100000546C713216920DC065767176C62C4540'      After this I would like to search tags for the selected node in `node_tags` table but my problem is that the database has 31 million rows, and the query takes more than 30 seconds. I have this columns in node tables:   * `id`, `version`, `user_id`, `tstamp`, `changeset_id`, `geom` I run the following sentence to ensure index in "geom" column:               CREATE INDEX idx_nodes_geom     ON nodes USING gist (geom );      But it doesn't work. Query takes more than 30 seconds. I have the following configuration in PostgreSQL database:   * **Shared buffers** : 768 MB   * **Work_mem** : 32MB   * **maintenance_work_mem** : 256 MB   * **wal_buffers** : 2 MB   * **checkpoint_segments** : 12   * **random_page_cost** : 2.0   * **seq_page_cost** : 1.0 Any idea to improve it?


title: Join a table to a parcel layer and get duplicate parcels, reflecting individual leases

text: I have a table of 3,000+ lease files that I'm trying to join to our parcel layer. Each parcel has 4+ leases associated with it, and I need each to be represented by an actual polygon. When I do a traditional join it joins 1 to 1, so it shows 1 of the 4 leases and the others do not join at all. Is it possible to join 1 parcel to many leases and have each show up as an individual polygon? I'm using Arc 10.1. Thanks in advance, Matt


title: check and validate the topology relationship between 2 feature class by concurrent users

text: my reqirement is allow several users to edit the map and validate the topology relationship between 2 feature class. Michael mentioned in my previous questions that I can only validata a topology when all users stop editting (which not tally to my requirement).Besides using the topology tool, what else can I use to check the topology relationship between 2 feature class. Thank you!


title: ArcHydro: Flow Accumulation 863988034 Cells

text: I've been using Arc Hydro for the last 7 years to determine catchment characteristics. I'm currently setting up a new model to determine structure locations along a proposed railway alignment. This is the largest study area I've ever had to process and currently its failing when I try to generate the Flow Accumulation Grid. My Flow Direction Grid for the study area has 863 398 034 cells. I'm looking for advice in how to successfully generate my Flow Accumulation Grid. If ArcGIS can't handle such large DEM's will GRASS be able to process such a large DEM and generate a ArcGIS GRID as an output that I could use for further processing of catchment characteristics. Thanks Peter.


title: How to efficiently project datasets of varying coordinate systems into one coordinate system?

text: I am working on streamlining data processing at my organization. Currently we are using various large-scale Models that we will gradually bring into Python. The gist of our data processing is as follows:   1. Collect data from sources (State, County, City, etc.)   2. **Project all data to a common coordinate system.**   3. Perform all sorts of processes on the data. I am currently concerned with part 2. The data comes in various coordinate systems. Our previous Models would run the ArcGIS Project tool individually on each dataset that needed it. Each Project tool in the Model would be projecting to the same output coordinate system, but some may require different transformation methods (or none at all). You can imagine having about 70 different datasets whose transformation methods are each manually assigned. It's ugly in code, worse in ModelBuilder. Most importantly, it is hard-coded to those specific datasets and therefore not reusable by another collection of datasets. **Ideally, I want to be able to choose a bunch of datasets, point them to a script tool, and reliably output them all in the same coordinate system.** I thought of importing all of the datasets into an ArcGIS Feature Dataset which will project all of the data automatically, but as blah238 pointed out in my previous question, it could be unreliable since it makes a 'best guess' on the transformation methods. **Are there any better methods, or any known tricks or custom tools?** My organization is mostly in the ESRI world, but I'm open to open-source solutions as well.


title: Calculating radius / buffer on EPSG 3785 in meters vs buffer in WGS 84 in meters

text: The goal is working in **EPSG 3785** and in particular Google Maps, one wishes to render (on a tile) a circle of a given radius in meters. The rendering is done in pixels. I would guess that one could take a very simple linear approach to identify the meters per pixel for a given tile zoom: `metersPerPixel = MercWorldWidthMeters / (2 ^ zoom) / tileSize` Now, considering you wish to draw a radius of let's say 100 meters around a point in pixels, then you convert to pixels: `pixelRadius = metersRadius / metersPerPixel` This _should_ in my mind produce a circle of **metersRadius** on the tile. However, actually measuring the produced circle's radius with a circle produced in WGS 84 and Great Circle logic, it shows that it is actually about 40% smaller than expected... a big difference. Does the logic above have a flaw? Note that I am **not** interested in finding an alternative algorithm (going to Great Circle calculations and the like)... my question here is " ** _why are the results (so much) different than expected_** ". All conversions this far have been working fine with the above logic but once I decided to calculate actual distance on EPSG 3785 I seem to be hitting a break wall. * * * To give an example with figures:               Radius: 0.08 miles ( = 128.74752 meters )     MercWorldWidthMeters: 20037508.342789 * 2     Zoom: 16     TileSize: 256      Above logic suggests a circle of **~107** pixels diameter.   Great Circle suggests a circle of **~175** pixels diameter.


title: getSelectedExtent not working on joined layers

text: When joining layers the getSelectedExtent function in ArcPy fails to get the extent. Unjoining the layers and running it yeilds the expected result. The joined layers are all located on an SDE. Is this a known issue or is there something I'm missing?


title: Locate DTEDs from one layer that intersect a polygon in another layer

text: I'm new to the GIS world, and using ArcGIS 10, so please forgive me if this is a simple question. I have DTED files (level 2) that I have placed into a mosaic dataset, and I'm trying to determine which DTEDs intersect a polygon in another layer. I'm using python, and used the SelectLayerByLocation method, but am having trouble getting the results from it. I can't use the CopyFeature method (which is what's in all the examples) because it's probably returning a mosaic layer instead of feature. I also tried the Copy method, but that didn't work either. Any suggestions? Here's that part of my code:                  arcpy.MakeMosaicLayer_management('CreateMosaicDataset', 'mosaic_lyr')        arcpy.SelectLayerByLocation_management("mosaic_lyr", "INTERSECT", buffershape)        # If features matched criterias write them to a new feature class        arcpy.Copy_management("mosaic_lyr", "DTEDs_for_Shape")      Update... **SOLUTION:                 # Create a Mosaic Layer from the mosaic dataset         arcpy.MakeMosaicLayer_management('CreateMosaicDataset', 'mosaic_lyr')         # Select DTEDs intersecting the polygon         arcpy.SelectLayerByLocation_management("mosaic_lyr/Footprint", "INTERSECT", buffershape)         # write selected features to a new feature class         arcpy.CopyFeatures_management("mosaic_lyr/Footprint", "DTEDs_for_Shape")


title: How do you find a lat/lon (DMS) on a paper map using a 30cm ruler?

text: How do you use a 30cm ruler to find DMS on a paper map? The locations I would like to find are the 'corner' points so I can generate an extent based on the four corners. I have an old paper map (3 actually) for Northern Canada (late 1800's) that doesn't provide the Ellipsoid or the Datum. It provides a representative fraction (1:660,000 approx) and a scalebar (1" = 10 2/3 mile). The map shows grid lines spaced every 1 degree. No minutes or seconds are labelled. I understand that NOT knowing the datum or ellipsoid will automatically introduce a margin of error into the calculations, but this is not a big deal for this exercise. I determined the Lat/Lon of the intersecting grid lines, and from this question, was able to infer that it is closest to Lambert Conformal Conic (Statistics Canada, EPSG 3347). Below is the index map showing all 3 maps with grid lines every 2 degrees: ![enter image description here](http://i.stack.imgur.com/RYHZI.png) _I will need to do this process for all three maps as those grid lines are spaced every 1 degree, and not 2 as in the index above._ * * * _Of course, I could geo-reference to a known spatial reference in a computerized GIS and digitize the extent, but what if your GIS is PC-less and you have traveled back in time and are now stuck..._ If it is easier to provide an answer using say, an engineers ruler (1:100, 1:2500 etc) then feel free. It's just a 30cm ruler seems to be more readily available in a given situation.


title: how to create thematic map using OpenLayers and Geoserver?

text:
I am still a beginner in learning GeoServer and OpenLayers. I tried to create thematic maps of the map that I publish in GeoServer. I used openlayer to show the map in web browser. When i want to create thematic maps based on data from the attributes that I have, I find the color constraints of thematic maps can not arise. What to make thematic maps should be used SLD in GeoServer? Here this code : indoprop /* General settings _/ body { font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-size: small; } /_ The map and the location bar */ #map { clear: both; position: relative; width: 600px; height: 600px; border: 1px solid black; }                   </style>

      sorry if a lot of mistakes. thanks for the positive response that you gave. I would say many thanks for all the answers that can help me because it's my final project which was a requirement for graduation from my college.


title: tiny JS discretization library for choropleth representation

text: I would like to know if a tiny stat/discretization js library ready to use exists. I do know about the existence of jStat (which I may explore a little bit more thoroughly), and I know that mapfish has a geostats module/widget to create choropleth map - I found the code here. But it relies on openlayers and I would like to have a standalone lib and eventually be free to communicate with openlayers. I would like to have few basics methods:   * min   * max   * mean   * median and be able to implement the following discretization with the ability to specify the number of classes and the precision (decimal):   * Quantile   * Equal Interval   * Natural Breaks (Jenks) If it does not exist yet, I will probably code something myself and release it on github under free license. Any resource and advice is welcome.


title: mapserver 5.6.6: polygon layer only rendered if crossing extent boundaries

text: I have two mapserver layers that get rendered only if the polygon boundaries are overlapping with the extent boundaries. ![Note the red polygons](http://i.stack.imgur.com/1qGls.png) If the red lines were below the upper rim of the extent, the layer would not be visible (no red square, no red polygon). Neither the inner red hollow polygon nor the outer red rectangle do display unless they intersect the image boundary no matter if at the top, bottom, left or right. Data come from a shapefile, it is not a DB query. The errorlog says the layer gets drawn:                   [Thu Jun 16 11:44:31 2011].947918 msDrawMap(): Layer 47 (simmodb), 0.014s     [Thu Jun 16 11:44:31 2011].973253 msDrawMap(): Drawing Label Cache, 0.024s     [Thu Jun 16 11:44:31 2011].973279 msDrawMap() total time: 0.621s      Why is that. Here is an extract of my mapfile:               MAP     CONFIG  "MS_ERRORFILE" "errorlog/mapsurfer-clean.log"     #CONFIG  "MS_ERRORFILE" "stderr"     #CONFIG  "MS_DEBUGLEVEL" "3"     #DEBUG 3 # can also set at layer level          NAME "MyProject"     STATUS ON     SIZE 600 440     RESOLUTION 96     #IMAGECOLOR 160 200 255     #IMAGECOLOR 253 250 170     IMAGECOLOR 255 255 255          #IMAGETYPE GD_PNG          IMAGETYPE AGGA          PROJECTION       #"init=epsg:4326"       "init=epsg:31468"           END     INCLUDE "mapfiles/outputformat.map.inc"                    #END               #EXTENT 11.2 50.8 14.8 53.6      #GK 4     # salzwedel oben         EXTENT 4443704.656113 5629700.821527   4685449.281400 5944601.022604          LAYER         NAME "geomodb"         GROUP "model boundaries"         TYPE POLYGON         STATUS ON         DATA "simgeomod/GEO-Modell"         CLASS             STATUS ON             OUTLINECOLOR 255 10 10             #COLOR 10 255 10             SIZE 20              END         #OPACITY 0              #DEBUG 3     END               LAYER         NAME "simmodb"         GROUP "model boundaries"         TYPE POLYGON         STATUS ON         DATA "simgeomod/SIM-Modell"         CLASS             STATUS ON             OUTLINECOLOR 255 10 10             #COLOR 140 100 255             #COLOR 10 255 10                                 SIZE 20         END         #STYLE OUTLINECOLOR 128 0 0 END         #OPACITY 30         #DEBUG 3     END      It does not change if layer status is set to DEFAULT.


title: Generating SLD dynamically using php in Geosever

text: I am fairly new to Geoserver and I have a question before I launch into something bigger than me: if i replace the XML code in the SLD style sheet inside geoserver with some PHP which generates the SLD dynamically (i.e. from a database query), will it work? How does Geoserver handle the SLD stored as style? Thanks in advance


title: Raster mosaic not displaying raster values ArcGIS 10

text: I have eight DEM tiles that I downloaded from the USGS National Elevation Dataset. The individual rasters are displaying correctly, but when I try to combine them in a Raster Mosaic I get arbitrary values (3.4+038 -> -3.4+038), which is considered to be NoData. I've tried several times, half the time I get a warning message upon creation of the Mosaic (001003: Datum Conflict) even though I was sure to match coordinate systems. I've even imported the coordinate system from one of the rasters going into the mosaic. _The mosaic shows the footprint of the DEM, but none of the data_ ![Mosaic](http://i.stack.imgur.com/mGEr4.png) I had a similar problem here, but I followed the process of converting to tif before I tried to mosaic the images.


title: How to query all points within the current map extent

text: First post - apologies if it's a simple question! I am basically looking to have a JS API service which will populate a datagrid with all of the points visible in the current map extent. As a user zooms in or out, the number of records returned will change to reflect what is in the current extent. I have been looking at the findPointsInExtent examples in the esri JavaScript examples, but am not sure how to edit the these examples to go from a user defined rectangle to the map extent as described above. Many thanks,


title: How to insert georeferenced PNG into correct location in AutoCAD Map3D?

text: I have a PNG of building plans that I will need to digitize in AutoCAD Map3D. I have georeferenced the PNG in ArcGIS, which has produced a world file (.pgwx) in the same directory in which the image is stored. When I attempt to bring this image into AutoCAD using either Insert Image or Data Connect, I am prompted to specify an insertion point. It is clearly not recognizing the resource file. **How can I open a georeferenced PNG in AutoCAD Map3D in the correct location?**


title: Consideration for a Good Silverlight based mapping application

text: I am starting to work on a Silverlight 4 based web mapping project using latest ArcGIS Server API. The application will involve multiple map services (for many themes) with selection, queries, and reporting for each map service. I am starting to gather some ideas on how to make this application extensible so that any additional map services can be added later on. For this project, in addition to map services, I will be using Oracle for backend for non- spatial data access. I am not sure if this will impose restrictions while building WCF services considering the fact that it's not SQL Server. I am looking for some feedback from folks who have implemented Silverlight based GIS solution and some of the factors that needs to be considered for a good/robust design. These would include: MVVM, logging, unit testing, security etc. Appreciate any ideas. Jay


title: How to configure QGIS Web Client?

text: I need to use QGIS Web-client to publish a research project on web. I setup the software on Windows and on Ubuntu Linux, changing the configuration as described in the README file and replacing the qgis_mapserv.fcgi with the server for the correct platform. Now I have the client on Windows which isn't working at all. On Linux I can load the helloworld.qgs example, but I see the dreaded pink screen. The 'natural' map is not loading, it keep going forever and without no one connection with the server. The QGIS server is working correctly on Windows and not really in a good way on Linux, but it doesn't matter. I need a working configuration for one system, OS independent.


title: Help projecting Austria data with QGIS

text: I'm trying to reproject this dataset from Austria Statistik Geodata. Data comes in "MGI_Austria_Lambert", and I'm trying to reproject to WGS84 What I'm doing is Saving layer as... and selecting EPSG:4326, but the layer is still in the same place. The other option i'm trying is changing the original .prj file with other one from a layer in EPSG:4326, but I have the same result. I don't what can I do to solve it. I'd really apreciate some help. EDIT: I've also tried setting the projection with:Set SRC to layer, and selecting 4326, but no changes.


title: Problem with Gpstools Plugin

text: I installed QGis 2.4 either with the standalone and Osgeo installers on a win7 Pro 64 laptop with 4 gb of RAM and I have the following problem When I invoke GpsTool either by the icon or the vector menu there is a long delay until the dialog box appears. Furthermore, I have a message that Qgis stops responding, a few seconds later I have the dialog box and I can use GPStools. Usually it takes between 15-20 second for the dialog box to appear. I tried to see if there is a log related to the issue by activating the log messages pannel but there is no record that something is going wrong. I even installed the Qgis 2.5 but I have the same symptoms. I would appreciate any help, Thanks before hand


title: Can QGIS map canvas update while python script is running?

text: I want to automate a periodic refresh of the QGIS map canvas with updated shapefiles. A Python plugin or console script does not allow the map to update until the script terminates. Is there a way to force a map refresh in a running plugin or script, or is a stand-alone app required? Using v1.7.4 now but could migrate to newer version.


title: How to move points to another polygon based on attribute?

text: I have a point layer and a grid cell/fishnet layer. Each point falls within a grid cell. Now I want to move some of the points to another (the nearest) grid cell based on an attribute that exists in the attribute tables of both layers. The attribute contains information on the neighbourhood. Some points fall within a grid cell where the value of this attribute is not equal for both layers. So, I want to move these points to the nearest grid cell that has the same value regarding this attribute. Does anyone have an idea? I use ArcGis 10.2 Advanced. Thanks for your help!


title: Change timestamps according to transportation used

text: I have a GPX file with about 500 numbered positions. Unfortunately the time stamps are not correct. I do however know the positions and times the transportation form was changed. For example:               Position 1 to 75:      starts at 07:00 stops at 07:45     transportation by foot at an average speed of 10 km/h          Postition 76 to 250:     starts at 07:45 stops at 10:00     transportation by train at an average speed of 180 km/h      How can I change the timestamps and use different increments for different forms of transportation? What tools could I use?


title: Can i export BUS routes from OpenStreetMap as shapefiles to work on ArcMap?

text: The OSM has all the routing for the buses in my city, even showing the ID of the bus if you zoom close enough. I know how to download the shapefiles with the roads, rails, etc., from Geofabrik, but the bus routing isn't included there. If I can't get access to this routes in ArcMap, I'll have to draw them one by one, which doesn't make that much sense since that work has already been done. Please, can someone help me?


title: Arithmetic on rasters with variable names in Map Algebra/Spatial Analyst?

text: I'm a Python (and StackExchange) novice trying to figure out how to perform calculations on temporary rasters with variable names. My attempt at a minimum working example is below, but I would eventually like to do this with thousands of larger grids, so I expect that I will need to keep everything temporary until the very end to increase efficiency. The code below fails on the last line. The error message is "RuntimeError: ERROR 000732: Input Raster: Dataset bin2 does not exist or is not supported". If I replace the last line with the permanent filenames:               tmpout = Minus("D:/tmp/tmp" + `year`,"D:/tmp/tmp" + `yearold`)      then it runs fine. I am running IDLE in ArcGIS 10.0 with Python 2.6.5 (r265:79096, Mar 19 2010, 21:48:26) [MSC v.1500 32 bit (Intel)] on win32.               import arcgisscripting     import arcpy     from arcpy import env     from arcpy.sa import *          arcpy.env.extent = arcpy.Extent(0,0,2,2)          arcpy.CreateRandomRaster_management("D:/tmp/","tmp1","","",1)     arcpy.CreateRandomRaster_management("D:/tmp/","tmp2","","",1)     bin1 = arcpy.Raster("D:/tmp/tmp1")     bin2 = arcpy.Raster("D:/tmp/tmp2")          for year in range(2, 3, 1) :         yearold = year - 1         binyear = "bin" + `year`         binyearold = "bin" + `yearold`         print "fails in next line"         tmpout = Minus(binyear,binyearold)      I _think_ the problem is that `bin1` and `bin2` are being interpreted as strings as opposed to pointer to temporary rasters, but I can't figure out how to make my intent understood. Replacing `binyear` with `Raster(binyear)`, for example, did not help. Any help would be appreciated.


title: Rotation by attribute in Geoserver SLD style

text: I have a table with field calculated by function:                  NEW."rotationAngle" := degrees(                              ST_Azimuth(                                 ST_StartPoint(NEW.the_geom)                               , ST_EndPoint(NEW.the_geom)                              )                           ) - 90;      Now i publish this table as Geoserver layer and set style with `Roataion` tag:                 <Rule>                 <TextSymbolizer>           <Geometry>             <ogc:Function name="startPoint">               <ogc:PropertyName>the_geom</ogc:PropertyName>             </ogc:Function>           </Geometry>           <Label>             <ogc:PropertyName>annotation</ogc:PropertyName>           </Label>           <LabelPlacement>            <PointPlacement>              <Rotation>               <ogc:PropertyName>rotationAngle</ogc:PropertyName>              </Rotation>            </PointPlacement>           </LabelPlacement>           <Fill>             <CssParameter name="fill">#FFFFFF</CssParameter>           </Fill>           <VendorOption name="spaceAround">10</VendorOption>           <VendorOption name="autoWrap">85</VendorOption>           <VendorOption name="group">yes</VendorOption>         </TextSymbolizer>         <LineSymbolizer>           <Stroke>             <CssParameter name="stroke">#000000</CssParameter>           </Stroke>         </LineSymbolizer>       </Rule>      And result: ![enter image description here](http://i.stack.imgur.com/A7HRm.jpg) How can you see label angle not equals line angle.   When i publish table as a SQL view:               SELECT gid, annotation,"fontSize", the_geom, degrees( ST_Azimuth( ST_StartPoint(the_geom), ST_EndPoint(the_geom) ) )-90 as angle from annotations      With same style i get result: ![enter image description here](http://i.stack.imgur.com/Lk7ZP.jpg) Label angle equals line angle.   Why it's hepping? What i do wrong in first case? **UPDATE** I checked angle values in both cases and they are same.   Table's geometry have a custom projection. When i publish it on Geoserver i reproject it in `EPSG:4326`. **Update** I changed function to:                  NEW."rotationAngle" := degrees(                              ST_Azimuth(                                 ST_Transform(ST_StartPoint(NEW.the_geom),4326)                               , ST_Transform(ST_EndPoint(NEW.the_geom),4326)                              )                           ) - 90;      But not help. **Update** I found interesting behivor. I setted Label text as `rotationAngle` property and open both layers in Layers Preview and results: View Layer: ![enter image description here](http://i.stack.imgur.com/SSeOh.jpg) Table Layer: ![enter image description here](http://i.stack.imgur.com/n4JQy.jpg) Table Layer in application (map projection EPSG:900913): ![enter image description here](http://i.stack.imgur.com/HaLyO.jpg) Just wft going on? **Solved** Of couse it was stupid. My application's map showed in EPSG:900913. So why i calculate rotationAngle in EPSG:4326? I dont know. This is correct function:                      NEW."rotationAngle" := degrees(                              ST_Azimuth(                                 ST_Transform(ST_StartPoint(NEW.the_geom),900913)                               , ST_Transform(ST_EndPoint(NEW.the_geom),900913)                              )                           ) - 90;


title: Use GDAL/Python to add rasters (tiff) to an ESRI File Geodatabase

text: I'm using GDAL python to create a bunch of tiff files from a netcdf file.               def modelout_to_geotif(netcdfile, outdir, VarName):         """ Given the path to the netcdf output,         produces geotiffs for each band of the given variable name.              Input::             netcdfile: string path to netcdf file             VarName: string variable name in netcdf file (e.g. 'GridPrec')              Output::             creates geotiffs for each 'band' (e.g. time step). Output is written             to current working directory.                   """         try:             nci = gdal.Open('NETCDF:{0}:{1}'.format(netcdfile, VarName))             ncd = Dataset(netcdfile)         except:             print "Could not open input file: {0}".format(netcdfile)             return              try:             geotransform = nci.GetGeoTransform()         except:             print "Could not get geotransform.\n"             return         try:             projection = nci.GetProjection()         except:             print "Could not get projection.\n"             return              numbands = nci.RasterCount         times = [o2d(t) for t in ncd.variables['time']]         print "Found {0} bands to process for {1}".format(numbands, VarName)         for i in range(numbands):             time = times[i]             band = nci.GetRasterBand(i+1)             raster = band.ReadAsArray()             y,x = raster.shape                  output_file = "{0}_{1}.tif".format(VarName, time.strftime('%Y%m%d_%H'))             subdir = os.path.join(outdir, VarName)             if not os.path.exists(subdir):                 os.mkdir(subdir)             output_file = os.path.join(subdir, output_file)             if os.path.exists(output_file):                 continue             # Create gtif             driver = gdal.GetDriverByName("GTiff")             #TODO: Make this more generic             dst_ds = driver.Create(output_file, x, y, 1, gdal.GDT_CFloat32 )                  # top left x, w-e pixel resolution, rotation, top left y, rotation, n-s pixel resolution             dst_ds.SetGeoTransform( geotransform )                  # set the reference info              dst_ds.SetProjection( projection )                  # write the band             dst_ds.GetRasterBand(1).WriteArray(raster)      Now I would like to add those to a mosaic catalog in an ESRI File Geodatabase. I've managed to get it working using arcpy, but it's really slow, and I'd prefer to use GDAL. Is there a way? Below is my arcpy script:               import os     try:         import arcpy         from arcpy import env     except:         raise ImportError("Unable to import arcpy - are you using ESRI Python?")          env = 'P:/Enki'               def add_to_mosaic(filegdb, raster_dir):                  print env         #Add Raster Dataset type Raster to FGDB Mosaic Dataset         #Calculate Cell Size Ranges and Build Boundary         #Build Overviews for Mosaic Dataset upon the 3rd level Raster Dataset pyramid         #Apply TIFF file filter         #Build Pyramids for the source datasets         varnames = ['GridPrec']#,                     #'GridSnowOut',                     #'GridRad',                     #'GridTemp',                     #'GridSoilOut',                     #'GridRunoff']              for VarName in varnames:             gdbname = filegdb              mdname = os.path.join(gdbname, VarName)             messages = 'Failed'             sr =  arcpy.SpatialReference()         #        sr.name = 'WGS_1984_UTM_Zone_32N'             sr.factoryCode = 32632             sr.create()             print sr              try:                 noband = 1                 res = None                 #TODO: get from input data                 print 'trying to create %s' % VarName                 res = arcpy.CreateMosaicDataset_management(gdbname, mdname, sr, noband)                  except:                 print res.getMessages()                                 rastype = "Raster Dataset"             inpath = os.path.join(raster_dir, VarName)             updatecs = "UPDATE_CELL_SIZES"             updatebnd = "UPDATE_BOUNDARY"             updateovr = "UPDATE_OVERVIEWS"             maxlevel = "2"             maxcs = "#"             maxdim = "#"             spatialref = "#"             inputdatafilter = "*200701*.tif"             subfolder = "NO_SUBFOLDERS"             duplicate = "EXCLUDE_DUPLICATES"             buildpy = "BUILD_PYRAMIDS"             calcstats = "CALCULATE_STATISTICS"             buildthumb = "NO_THUMBNAILS"             comments = "Add Raster Datasets"             forcesr = "#"                  res = arcpy.AddRastersToMosaicDataset_management(mdname,  rastype, inpath, updatecs, \                                                        updatebnd, updateovr, maxlevel, maxcs, \                                                        maxdim, spatialref, inputdatafilter, \                                                        subfolder, duplicate, buildpy, calcstats, \                                                        buildthumb, comments, forcesr)             print res.getMessages()


title: Algorithm behind custom tool of ArcGIS for Desktop called xyz2grid21?

text: I am a researcher from Romania and I have used `xyz2grid21 ArcGIS tool` (by Min-Lang Huang) in order to convert xyz files (LIDAR data) to ASCII and ESRI grid in order to obtain a DTM. I need to know what algorithm does the XYZ2GRID tool use in order to rasterize the data? Is it using a mean or minimum value or does it interpolate somehow?


title: Creating weight raster for flow accumulation in ArcGIS for Desktop?

text: I am studying flood flow using ArcGIS for Desktop. When creating flow accumulation in hydrology, there is a weight raster. However, İf you do not have it, the programme sets its value to 1 which is not a suitable approximation for the simulations. How can I create a weight raster in ArcGIS for Desktop?


title: geometryType property of Vector Layers in OpenLayers

text: ## **ORIGINAL:** I have a couple questions that are focused around the geometryType property with vector layers. When you create a vector layer you can set the geometryType property to limit the geometry types the layer supports... > {String} geometryType allows you to limit the types of geometries this layer > supports. This should be set to something like “OpenLayers.Geometry.Point” > to limit types. -- OpenLayers API Docs but in the Vector.js file the code is looking for an object when checking the geometry                if (this.geometryType &&               !(feature.geometry instanceof this.geometryType)) {                 var throwStr = OpenLayers.i18n('componentShouldBe',                           {'geomType':this.geometryType.prototype.CLASS_NAME});                 throw throwStr;               }      _Is this a typo in the API Docs or am I doing something wrong here?_ On a related note if I set the geometryType of a VectorLayer to be **OpenLayers.Geometry.Polygon** and then try to edit geometry of features in that layer it doesn't want to work because it tries to insert **OpenLayers.Geometry.Point** geometries into the layer to represent the draggable vertices. _Is there a something built in to get around this or do I need to write something to handle this?_ Thank you for any help. ## **UPDATE:** This seems to work but I'll be running more tests. _Vector.js_                   // Override for geometryType.         var geometryType = options && options.geometryType !== undefined ? options.geometryType : this.geometryType;      _ModifyFeature.js_               // Where "addFeatures" exist I've tacked on the geometryType     this.layer.addFeatures([this.radiusHandle], {silent: true, geometryType: OpenLayers.Geometry.Point});      Thanks for the help!!


title: ogr SetAttributeFilter uppercase?

text: How do I use the ogr `SetAttributeFilter` with uppercases? Code example:               lyr = shp_obj.GetLayer()     sel_str = "%s = '%s'" % (field, value)     lyr.SetAttributeFilter(sel_str)      Can I just do:                sel_str = "UPPER(%s) = '%s'" % (field, value)      ?


title: cannot download 3rd party plugins in qgis

text: 1. I want to download SDA4PP plug-in in QGIS. Unfortunately I cannot see the button to download 3rd party plugins, as indicated in the install instructions at that link. I am using this program on a company network. I have put in some proxy settings which mean that I can access the global/official repository. Before I did this I could not even access this. When I go to the plugins tab though there are only a few listed and when I put something in the search box nothing comes up, i.e. it only searches currently downloaded plugins (those that came with the install). Anything I'm missing?


title: All LGAs for Australia in KML or KMZ format

text: Can somebody please show me where to find a KML or KMZ file that includes the digital boundaries for all Local Government Areas in Australia? Thanks!


title: Openlayers Plugin, Project CRS and Grids in Composer

text: Apologies in advance for the potential for this to be a duplicate question, I've had a good look, and I can't see a solution thatI understand well enough to help me. I have my project CRS set to a local UTM projection, however when I add a map from Open Layers the Project CRS changes to EPSG:3857. When I add a grid in composer, I need to display the longs and lats of the local UTM, not the Open Layer EPSG. I understand that I need to have the Project CRS the same as the Open Layers CRS, but is there a way I can 1) save and reproject the section of the Open Layer raster into my local UTM, so it still lines up with my vector layers or 2) display the appropriate coordinates on the grid, despite the Project CRS being in EPSG:3857. This is an issue that I have with many of my maps, where I use aerial imagery for my base layers, but need to display local coordinates in my final map. Will there be an easy solution to this in QGIS 2.0?


title: GeoExplorer: "Could not create layer record for layer group"

text: I installed GeoServer via OpenGeo Suite, and still working on it. I created a "Layer Group" and add layers from local PostGIS. I tried to preview it from "Layer Preview" and show perfectly through the "OpenLayers" option, but unable to show in "GeoExplorer". I got the javascript warning message says: `"Could not create layer record for layer 'testgroup'. Check if the layer is found in the WMS GetCapabilities response."` on GeoExplorer.js:1441 To view the source code shows like:               1441: {name:"fixed",type:"boolean"},{name:"selected",type:"boolean"},{name:"restUrl",type:"string"},{name:"infoFormat",type:"string"},{name:"getFeatureInfo"}];c.fields.each(function(a){i.push(a)});b=new (GeoExt.data.LayerRecord.create(i))(h,b.id);b.json=a}else window.console&&0<this.store.getCount()&&void 0!==a.name&&console.warn("Could not create layer record for layer '"+a.name+"'. Check if the layer is found in the WMS GetCapabilities response.");return b},getProjection:function(a){var b=this.getMapProjection(),         "Could not create layer record for layer 'testgroup'. Check if the layer is found in the WMS GetCapabilities response."     1442: c=b,a=a.get("srs");if(!a[b.getCode()]){var c=null,d,e;for(e in a)if((d=new OpenLayers.Projection(e)).equals(b)){c=d;break}}return c},initDescribeLayerStore:function(){var a=this.store.reader.raw;this.lazy&&(a={capability:{request:{describelayer:{href:this.url}}},version:this.version||"1.1.1"});var b=a.capability.request.describelayer;if(b)a=a.version,1.1<parseFloat(a)&&(a="1.1.1"),a={SERVICE:"WMS",VERSION:a,REQUEST:"DescribeLayer"},this.describeLayerStore=new GeoExt.data.WMSDescribeLayerStore({url:this.trimUrl(b.href,      I am sure that I can preview them separately in GeoExplore from "Layer Preview" page. It seems everything goes well when I checked it from `http://localhost:8080/geoserver/wms?SERVICE=WMS&REQUEST=GetCapabilities`, without any error massages or exceptions shown, and the layer group description show at the bottom of the page. Does anyone run into the same problem? **//UPDATE** I found that I missed a javascript error massage when I view the `REQUEST=GetCapabilities` page. It says: `"Uncaught TypeError: Cannot set property 'boxSizing' of null"` on ContentVeil.js:11 To view the source code shows like:               11: veil.style.boxSizing = "border-box";         "Uncaught TypeError: Cannot set property 'boxSizing' of null"     12: veil.style.borderStyle = "solid";      I am wondering where the error comes from. Furthermore, I cannot load the **"field list"** when editting limit condition in style's rules in GeoExplorer.


title: QGIS 2.4.0 How to display only selected features on map?

text: Not sure if this option ever existed, but the new QGIS version hides a lot of things somewhere else and this seems so simple that I'm kind of convinced it was possible to do this before. I have quite a large data set with ship tracks. I now want to analyse individual ship tracks (made from point layer with points2one) - however, it is so crowded that it is hard to look at individual tracks. I don't want to save each single track as a new layer, so I wonder if it is possible to select one track in the attribute table and display only that one on the map/hide the others? Thanks a lot!


title: Combining multiple year yield data in ArcGIS for Desktop?

text: I am using ArcGIS 10.1 for Desktop and trying to find the simplest way to combine multiple year of crops yield data into one file and get the average yield. The files are point files from a yield monitor.


title: How to split polygons at intersections in ArcGIS 9.3?

text: I have two polygon layers. I'd like to split the features in one based on where they intersect the other layer. I've tried using the Clip tool, but there is no option to simply split the features -- you're either left with all of the overlapping parts or non-overlapping parts. I've found several Cut Features tools in some obscure extensions in 10.1, but unfortunately I don't have access to those. Can anyone advise on how to do this in out-of-the-box 9.3.1? **UPDATE** I'm using an ArcInfo license. Here is a visual of what I'm trying to achieve: ![enter image description here](http://i.stack.imgur.com/X2vEe.png)


title: Import error:No module named _gdal

text: I have installed python 2.5.1 and FWTools2.4.7 in my laptop(Windows 7) when i run my pythonscript in FWTools i get following error Import error:No module named _gdal can any one suggest how to solve this problem?


title: ogr2ogr does NOT save "styles", say "color", information; how do I get around it?

text: I'm using `ogr2ogr` to convert KML to GeoJSON and I'd like to extract style information along with the data. The bash script I am using is:               filekml="/tmp/poly.kml"     filegeojson="/tmp/poly.geojson"          ogr2ogrProg="/usr/local/fwtools/FWTools-linux-i686-3.1.0/bin_safe/ogr2ogr"          # randomNum=14089918888     randomNum=`date '+%s'`          # Grab the National Weather Service Polygon (KML) data file, using SH script in Linux:     getFromURL="http://www.srh.noaa.gov/data/radar/poly.kml?${randomNum}"     wget ${getFromURL}     echo y | mv poly.kml\?${randomNum}  ${filekml}          #-- use OGR program above to convert the downloaded KML file to geoJSON format     rm -f ${filegeojson}     $ogr2ogrProg -f "GeoJSON"  ${filegeojson}  ${filekml} -nln sr_polygon          # ---- examine the KML file and its' sister geoJSON file     vi /tmp/poly.kml /tmp/poly.geojson      You will notice KML contains lines like these: ==> color ffa9a9a9   ==> scale 0.5   ==> href http://www.srh.noaa.gov/ridge/graphics/FFW.gif   BUT--- geo JSON file has absolutely NO information on STYLE (that was embedded in KML).


title: searching data from wms geoserver in jquery mobile

text: hye all, need someone help, i use template from openlayer using jquery mobile, im really new in openlayer, i want to search data in wms, the coding is below $('#searchpage').live('pageshow',function(event, ui){ $('#query').bind('change', function(e){ $('#search_results').empty(); if ($('#query')[0].value === '') { return; } $.mobile.showPageLoadingMsg();                   // Prevent form send         e.preventDefault();              var searchUrl = 'http://ws.geonames.org/searchJSON?featureClass=P&maxRows=10';         searchUrl += '&name_startsWith=' + $('#query')[0].value;         $.getJSON(searchUrl, function(data) {             $.each(data.geonames, function() {                 var place = this;                 $('<li>')                     .hide()                     .append($('<h2 />', {                         text: place.name                     }))                     .append($('<p />', {                         html: '<b>' + place.countryName + '</b> ' + place.fcodeName                     }))                     .appendTo('#search_results')                     .click(function() {                         $.mobile.changePage('#mappage');                         var lonlat = new OpenLayers.LonLat(place.lng, place.lat);                         map.setCenter(lonlat.transform(gg, sm), 10);                     })                     .show();             });             $('#search_results').listview('refresh');             $.mobile.hidePageLoadingMsg();         });     });     // only listen to the first event triggered     $('#searchpage').die('pageshow', arguments.callee);      }); really need anyone help Thanks


title: What is the process to calculate Helmert parameters?

text: I have some double points (the same points in 2 different datums). I'd like to calculate the Helmert parameters but I don't understand how. NOTE: I don't need software. I need an algorithm in order to write a small Delphi application.


title: How do I export symbology to ArcGIS Online?

text: We're planning to put up a bunch of our maps into ArcGIS Online and we'd like to create a streamlined process to do so, with as much automation (Python) as possible. This is our first test with a map of a city park with lots of unique symbols. We figure we'd get a map up there, then figure out what can be scripted. Anyhow, so, we have an .mxd of a park where pretty much each layer has fancy symbols for things like parkbenches, bathrooms and the like. Upon fiddling around with ArcGIS Online, it looks like it only takes .txt, .csv, and .gpx files. I managed to get layers into "My Content" but it doesn't let me add it into a map. When I go "Add>Search for Layers" and tell it to search in My Content, nothing shows up. I then shared the layer in My Content so it was public on ArcGIS Online, and tried seeing if the search func. would see the layer in ArcGIS Online. No luck. How do I get it to take attribute data, but also the symbology data from my layers? I hope that made sense. Will definitely clarify as much as needed.


title: How to use ST_Intersection?

text: Here's a quick summary about what I'm trying to do: I have 3 tables in Postgres, 'a' and 'b', each have a Polygon column, and 'c' has a Point column. What I'm trying to do here is to get the geometries intersections between 'a', 'b' and 'c', and to display such geometries on an OpenLayers vector layer. I already know how to display any kind of geometry from a String in OpenLayers, but I'm having troubles with the PostGIS' ST_Intersection function, I'm doing this:               SELECT ST_Intersection(a.geom, b.geom) as inter from a, b;      where a.geom and b.geom are both the geometry columns, and I get this error message:               NOTICE:  TopologyException: found non-noded intersection between 515172 2.14408e+06, 497067 2.13373e+06 and 501321 2.13546e+06, 471202 2.14843e+06 500621 2.13576e+06      ERROR:  GEOS Intersection() threw an error!      Also I tried to express the resultant geometry as text using ST_AsText like this:               SELECT ST_AsText(ST_Intersection(a.geom, b.geom)) as inter from a, b;      but it send me this error message:               HINT: No function matches the given name and argument types. You might need to add explicit type casts.      I don't know what I'm doing wrong, I just want to get the Polygons' WKT to display it on OpenLayers, here's how I display a geometry from a WKT:                                   var in_options = {                             'internalProjection': new OpenLayers.Projection("EPSG:4326"),                             'externalProjection': new OpenLayers.Projection("EPSG:4326")                         };                               var fea= new OpenLayers.Format.WKT(in_options).read(data); //data is the string with the WKT                         vectorLayer.addFeatures([fea]); //this piece of code works great                         map.zoomToExtent(bounds);      UPDATE: I tried the next:               SELECT ST_Intersection(a.geom, b.geom) as intersect_ab FROM a INNER JOIN b ON      ST_Intersection(a,b) WHERE ST_Overlaps(a.geom, b.geom)      AND ST_isvalid(a.geom)='t' AND ST_isvalid(b.geom)='t';      but I get the next error message:               ERROR: Function st_intersection(a,b) does not exist.     HINT: No function matches the given name and argument types. You might need to add explicit type casts.      I added the isvalid to verify only valid polygons are being evaluated, but it's telling the error is in the ST_Intersection(a,b), both a, b and c have the same SRID so I'm really confused, sorry if I'm asking too much, but I'm quite new with PostGIS so I hope I'm not bothering you a lot. Thanks.


title: Access Metadata from ArcSDE-tables using python

text: Is it possible to access the metadata of a feature class in a ArcSDE-data, using arcpy / python (on Arcgis 10.0). I suppose I could export the metadata to xml and parse the xml, but is there a more direct approach? I need to make a summary table of all the data in our database, with several elements from the metadata (author, last update etc. ). We always enter metadata for each new dataset in our DB.


title: Map tiles and max/min latitude and longitude

text: I'm trying to build a map based on a center point lat/long, the map will always be a fixed size say 1024 by 1024. The user can chance the center point and zoom. If I populate the map with map tiles from map quest for example, is there someway I can know the max/min latitudes of the map currently being displayed? I want to know this so I can accurately project things onto the map. Thanks


title: How to extend Geoserver raster data sources

text: I am new to web GIS world. I have installed Opengeo Suite on my PC running with Windows 7 operating system. So, geoserver is locally installed (http:localhost:8080/geoserver). I have tried to import shapefiles into geoserver. Now I want to import .ECW and .JPEG image into Geoserver. When I click _stores_ and _add stores_ , I can see the following list of rasters,![enter image description here](http://i.stack.imgur.com/Mm70M.png) I looked into the following path and found that image extraction files are installed there, C:\Program File\OpenGeo\OpenGeo Suite\webapps\geoserver\WEB-INF\lib ![enter image description here](http://i.stack.imgur.com/lniGx.png) From internet search, I found that some people have advised to install gdal- data in the above mentioned path. I extracted gdal-data into the _lib_ directory, ![enter image description here](http://i.stack.imgur.com/oUVHc.png) Now I restart OpeGeo dashboaard and geoserver, still I cant see .ECW or :JPEG foramt in the raster data sources. Can anyone help me out?


title: How to convert shape files (.shp) to Cad (.dwg ) format using Quantum Gis 1.7.0?

text: How to convert shape files to .dwg format using Quantum GIS 1.7.0 ? Thank you


title: Request to run mapbasic 10.5 code in mapbasic 9.1 version

text: I have created mapbasic codes using 10.5 version. Now I have to run in a lower version (9.1) Please anyone help me how to do this.. How to copy paste the program codes from 10.5 version to 9.1 version? Thanks, Jagan


title: Set feature attribute by name via QGIS python api

text: I try to set feature attributes by attribute name with this code               pr = layer.dataProvider()     pr.addAttributes([QgsField("test", QVariant.Int)])     layer.updateFields()     for feature in layer.getFeatures():      attrName = 'test'      feature[attrName] = 1      but in result I have NULL in all fields. If I use               feature.setAttributes([1])      it works properly. What I do wrong? Why feature[attrName] = 1 doesn't work? **Update** : Find this solution               pr = layer.dataProvider()     pr.addAttributes([QgsField("test", QVariant.Int)])     layer.updateFields()     for feature in layer.getFeatures():      attrName = 'test'      feature[attrName] = 1      pr.changeAttributeValues({feature.id() : {pr.fieldNameMap()[attrName] : 1}})


title: Stray horizontal lines after converting from GeoJSON to topojson

text: After converting a GeoJSON file to topojson, and loading the topojson into Leaflet, stray lines appear in the resulting map. Like this: ![enter image description here](http://i.stack.imgur.com/QBjcy.jpg) What is causing this? If I view the GeoJSON, these stray lines do not appear. I've played with the quantization behavior, and this does not seem to help. thanks. (I am using Leaflet-Omnivore to digest the topojson.)


title: Showing data in form view (instead of grid view) using ArcGIS API for JavaScript?

text: Can anyone suggest how to bind data with the help of query in a Form view of the ArcGIS API for JavaScript? I have done it in Grid view but as the requirement of a client is that I have to bind it to a Form view.


title: How to create animated timeline in ArcGIS for Desktop?

text: I can't find any options in ArcGIS timeslider to create a timeline like presented in this video. The video itself is a guide for creating time animation, but no information is given how to create such timeline like in the end. I have tried to search some information about that and can't find anything usefull. Does ArcGIS support such functionality? **UPDATE 1:** I need an autorefreshed timeline (which is presented not as usual date text). It should be animated line where each date is a vertical line on a timeline. Also I need to label each date on it as a text. See picture below (frame by frame animation). ![enter image description here](http://i.stack.imgur.com/qEMpX.gif) Added a post at ArcGIS Idea, to add such functionality. Upvotes are welcome.


title: QGIS: drawing order of lines and polygons (line between polygon)

text: I have 2 layers. One with forests and lakes (polygon) and one with rivers (line). Now I want the features to draw in that order: The river have to be UNDER the LAKES and the forest have to be UNDER the river and OVER the lakes. Tricky? Because I have to export as vector-pdf, I can not use the feature blending modes. (or is there a hidden way to export blending modes to vector? I need the borderlines of the lake and the river. I can not physically change the layers. ![enter image description here](http://i.stack.imgur.com/UA8Aa.png) ...or is there a other way to draw the river flow into the lake?


title: Inserting full bleed images in browser background instead of maps using CartoDB?

text: I am building a product that will utilize high fidelity photography. I would like to show my photos in a slideshow format that takes up the entire area of the browser. CartoDB and the Odysssey.js would work well. Can I substitute the maps for photography in the background of my browser?


title: Grass7 - r.regression.multi and new raster

text: I am on the learning curve with Grass7. I managed to make r.regression.multi work, but there is one thing that would be of high interest for me: it is possible to create a new raster showing the results (residuals) of the analysis in a new raster? This would enable me to nicely locate the areas with high residuals.


title: How to add the current document path on Print Composer?

text: I'm trying to demonstrate to my company that we can begin using QGIS in conjunction with (and sometimes even instead of) ArcGIS and MapInfo. I've started setting up some layout templates but have run into a. In Print Composer, is there a way to add the current project path? In ArcGIS, the dynamic text is:               <dyn type="document" property="path"/>      I'd prefer not to have to copy/paste the document path every time I make a map. * * * **EDIT:** _To address answer and comments by artwork21 and Nathan W:_ I'm using QGIS 2.0.1. I would also like this path to appear to anyone who may need to open the project for editing without modifying their `startup.py` file.


title: Automated quality control and assurance - geodata?

text: I've recently started looking at the issue of automated quality control and assurance of geographic data. What software exists that can be used for accomplishing this? Esri has got their product 'Data Reviewer' which seems interesting, are there any comparable alternatives to this product? I would like to tag this question with quality-control and quality-assurance, but can't do so.


title: Don't route through bollards, concrete blocks, etc with osm2po

text: Is it possible to prevent road segments being used when these are blocked by bollards, concrete blocks or the like? I have one example where there the road Solhøjvej is blocked with a so called concrete block as you can see here http://www.openstreetmap.org/?lat=57.010248&lon=9.936238&zoom=18&layers=M Here is a photo of the "block": https://maps.google.com/?ll=57.010343,9.934331&spn=0.000929,0.00284&t=m&layer=c&cbll=57.010252,9.934346&panoid=SrWxGTFwoDbDZeDgXHl8vg&cbp=12,10.73,,0,10.62&z=19 I’m exporting the Openstreetmap to PostgreSQL using osm2po and performs routing, but this does not know of these concrete blocks or bollards or stuff blocking the road. I’m aware that this is perhaps not a simple task, to detect and split road segments when such obstacles occur, but that would be very useful. Am I just missing an option?