14
votes
2answers
3k views

Using Geodesic Measurements for Circle Radii?

I am currently developing an OpenLayers mapping site. Measurements can be made using a line tool, and an area tool. Both of these are currently set to calculate geodesic measurements as outlined in ...
8
votes
8answers
7k views

Splitting shapefile into separate shapefiles for each feature using QGIS/GDAL/SAGA?

I have a polyline shapefile with about 20 kinds of roads. I would like to know how can I create automatically a vector file for each one. I am aware of how to do it using ArcGIS for Desktop - see ...
4
votes
2answers
279 views

Assign point IDs to respective start and end attributes of a polyline

I have two shapefiles, Point and Polyline. I'm trying to populate my polyline layer with the point data ID (systemID) where the lines start to where they end; eg. create two columns (from and to). The ...
4
votes
2answers
1k views

How to automatically reloaded raster layer if source is changed in QGIS?

How to automatically reloaded raster layer if source is changed? (The path is the same but inside source file are changes) I use: qgis.utils.iface.mapCanvas().refresh() but layer not refresh. # ...
1
vote
1answer
418 views

Apportion Neighborhood Information to Census Tracts

I have a shapefile of census tracts and another shapefile of "neighborhoods" with values that I need to have joined to the census tracts. I know I need to apportion the area of the neighborhood ...
1
vote
2answers
283 views

How to define Subroutines and functions?

I am working in VBA. My error is sub and function are not defined. Here is my code: Private Sub CreateMap(cboDistrict As String) Dim mapDocument As New mapDocument If ...
40
votes
7answers
4k views

Best practices for PostGIS production environments?

What PostGIS documentation have you come across that has been helpful when tuning PostGIS for a production environment? I would like to get together with my DBA to setup a Postgresql/PostGIS ...
38
votes
2answers
4k views

Acquiring ArcGIS-like speed in Postgis

I have been using Postgis 2.0 for 3/4 of a year now and while I really enjoy using it, excessive query processing time has rendered it basically unusable for my use case. I tend to do heavy ...
35
votes
7answers
5k views

How can I effectively debug arcpy Python scripts?

I have written many Python scripts using arcpy in ArcGIS 10, and so far my only means of debugging is restricted to printing messages to the geoprocessing results window using arcpy.AddMessage(). Are ...
38
votes
4answers
2k views

What are the FOSS equivalents to these ArcGIS products?

I'm a long-term user of ESRI software, and I now have a need to use free and open source software. I've been reading about Open Layers, PostgreSQL, PostGIS, GeoServer and MapServer but I can't find ...
20
votes
9answers
6k views

How do I develop my GIS programming skills?

I would like to develop my GIS programming skills, where do I start? People say learn C++ or Python but where can I learn this in a geographic context? Tutorials or anything would be very helpful, as ...
33
votes
6answers
11k views

Downloading OpenStreetMap Data

Is there a straightforward way to download data from OpenStreetMap (OSM)? Using North America as an example, I realize Cloudmade (http://downloads.cloudmade.com/north_america) and geofabrik ...
26
votes
9answers
14k views

How to connect to PostGIS database from ArcMap?

How can I connect to a PostGIS database from ArcMap? Solutions for ArcGIS 9.3, 10.0 and later are acceptable. Ideally, I would like to be able to perform spatially enabled queries and receive the ...
22
votes
3answers
15k views

How to convert ArcGIS .mxd file to QGIS .qgs file?

I recently tried to use QGIS and I wondered if you can convert a draft ArcGIS map (*.mxd file) into a QGIS project (*.qgs file). This would avoid thematize the entire project.
17
votes
8answers
5k views

When Versioning with ArcSDE can posted edits be cancelled or rejected?

I am using ArcGIS 9.3.1 and attempting to work with an SDE geodatabase (with one polygon feature class) that has already been registered as versioned. I'm new to versioning and am still trying to ...
17
votes
4answers
21k views

How do you decide what interpolation method to use for resampling raster data?

The question pretty much says it all; are there hard and fast rules about which interpolation methods are suited to each kind of raster data? Any Golden rules, rules of thumb? Good books or articles ...
21
votes
5answers
3k views

How to create regular point grid inside a polygon in Postgis?

How to create, inside a polygon, a regular grid of point spaced x,y in postgis? Like the example:
9
votes
1answer
1k views

Creating table containing all filenames (and possibly metadata) in File Geodatabase?

I need to create a metadata-table for all files in a File Geodatabase or Spatial Database. It would be awesome if it were possible to automatically be updated with new filenames, and possibly even ...
27
votes
3answers
10k views

How to make a spatial view in PostGIS and add it as a layer in QGIS?

In PostGIS 2.0, what is the most efficient way to create a spatially enabled view that is viewable in QGIS? I followed the context of Part 2 of @Mike Toews answer to this question, and the view ...
20
votes
2answers
7k views

How can I convert data in the form of lat, lon, value into a raster file using R?

I have a data set of values over a km grid in the continental U.S. The columns are "latitude", "longitude", and "observation", e.g.: "lat" "lon" "yield" 25.567 -120.347 3.6 25.832 ...
20
votes
3answers
1k views

Packing Polygons within polygon

I have a Boolean raster. In the grey areas of the raster I would like to fit a given size polygon within a contiguous extent. Basically, I have an irregular polygon, and i would like to "fit" a ...
8
votes
2answers
624 views

Creating summary table of symbology of all datasets in multiple MXDs?

This is related to the following Retain ESRI symbology in Mapinfo TAB . As an initial step (in arcpy) I want to access the symbology of all the datasets and create a document which has the details of ...
20
votes
10answers
22k views

Adding Attribute data to shapefile?

I can display a shapefile in openlayers but I need to add some attribute data. I can open the dbf file in excel but there is no save as option in excel to the updated file as a dbf. What is the ...
18
votes
5answers
24k views

How do I create point features with exact coordinates?

How do I create point features with exact (manually entered) coordinates in QGIS? I get precise GPS coordinates from a survey team which I need to add to a point layer. What I want: -Add point, type ...
11
votes
2answers
5k views

How to check Topology in QGIS?

I have two Shapefiles with Polygons ( City and Forerst) Is there a Plugin who is able check the topology (QGIS)? Like "Knots do not overlap" or something like that? I dont want that they overlap. ...
8
votes
2answers
14k views

How to crop Shapefiles in QGIS?

I need to clip a large and very detailed .shp file in QGIS showing environmental data similar to a temperature map. Is there something like the very simple crop tool alike in photoshop where you can ...
6
votes
2answers
744 views

How to create an oriented buffer using arcpy?

I would like to create an oriented buffer for every polygon in my shapefile using arcpy. By oriented I mean that I have two angles a1 and a2 that constraint the direction of the buffer. This is ...
6
votes
3answers
8k views

How to convert coverage (.adf) to shapefile?

Is there any tool or software except ArcGIS which I can use for converting coverage (.adf) files to shapefiles?
13
votes
2answers
2k views

Which function for creating a POINT in PostGIS?

When defining a Point in PostGIS, when do you decide to use which of the following? ST_SetSRID(ST_MakePoint(lon,lat),4326) ST_SetSRID(ST_Point(long,lat),4326) ST_SetSRID(ST_GeomFromText('POINT(lon ...
8
votes
5answers
6k views

How to change the order of features in a shapefile?

I have a shapefile and I want to change the order of the features. Is that possible?
6
votes
2answers
1k views

ArcObjects + comtypes at 10.1 and newer

Has anyone played around with using ArcObjects in Python at version 10.1? I am having all sorts of problems, such as TypeErrors when wrapping the ESRI OLB modules and AttributeErrors when attempting ...
14
votes
6answers
6k views

Recalculating full extent of File Geodatabase feature class?

I have a featureclass in an Esri file geodatabase. When I edit the features using the editor in ArcMap, and I delete most of my features and keeping only the ones in the middle, the zoom to layer ...
9
votes
2answers
1k views

Inserting newlines in Rectangle Text elements via ArcPy causes overlap?

I ran across an issue the other day when I tried to use ArcPython's mapping module to edit rectangle text elements with newlines (\n) in an ArcMap document. Here's what the output looked like: ...
7
votes
2answers
3k views

How to re-order fields permanently using ArcGIS Make Query Table tool?

In the Answer to somebody else's question it was stated that the Make Query Table tool could be used to re-order fields in tables and feature classes permanently. However, when I open the dialog for ...
6
votes
3answers
3k views

How to read Greek fonts (ISO-8859-7) in shapefile attributes within QGIS 1.8.0?

I'd like to ask whether there is a way to read greek fonts in a shapefile's attribute table within QGIS 1.8.0.
6
votes
1answer
6k views

How to add automate values to attribute field?

I have parcel, Buildings layers, without any information attribute table, and i want to replace "NULL" values with numbers form 1 to 2000, in "Parcel ID", or "Building ID" field thank you.
6
votes
1answer
2k views

How to force ArcGIS to recognize a text field in a CSV file?

Related to Data-type detection in ArcGIS table loading I have a CSV file which contains a mixture of numeric and text fields: ID,Txt,Int,Dbl 12345,abc,45,56.78 12346,9,65,23.12 12347,10,66,23.13 ...
6
votes
1answer
4k views

How to create a point along a line given distance

I have been given a non-spatial database which contains the names of lines which I have a shapefile for. The database also has names of points and the distance of each point from the origin along the ...
4
votes
2answers
4k views

How to generate a DEM from a contour Shapefile?

I want to create a DEM from depth contours (shapefile) in QGIS. I've been trying to work out how to do this based on this previous question, notably from this link from that page, however I'm stuck, ...
12
votes
5answers
9k views

How do I create a convex hull in ArcGIS Desktop?

I would like to be able to create a convex hull in ArcGIS Desktop 9.x, but I cannot find an appropriate tool. How does one go about creating one? I am interested in answers for all license levels: ...
8
votes
3answers
1k views

When do I need to use a proxy with OpenLayers?

When exactly do I need to use a proxy with openlayers? I've done a lot of reading on this but can't seem to find a difinitive answer. Wondering if this is the route of my problems. For instance, if I ...
5
votes
2answers
894 views

Identify the latitudinal and longitudinal point directly beneath an object in space

Given the azimuth and altitude / latitude and longitude from the observer to the satellite, how can I accurately find the latitude and longitude of the point of intersection directly under the ...
5
votes
2answers
3k views

How to add links to PDFs in a Shapefile?

I have a problem. I want an attribute in a shape file named "Link" to add. The works are all fine. But then I would like to add a link in my directory. This link accesses a PDF. Now, this PDF is not ...
5
votes
1answer
821 views

Qgis polygonize problem - DLL load fail

I have a raster file and I want to perform the method "polygonize". Then the problem occurs, that is shown on the screenshot. It doesn t have anything to do with the rasterfile format, I veryfied. ...
5
votes
2answers
6k views

How to sort a feature class and then calculate a sequential ID field?

I am in ArcMap and I want to sort the records based on a field and then do a Calculate Field with an auto-incrementing value with the sort in-place. Any ideas? It looks like I could get an update ...
4
votes
2answers
10k views

Create polygon layer from polyline layer

Our systems expect polygon shapefiles, representing a collection of non-intersecting and geometrically valid (multi)polygons. Specifically, farm fields. We often receive our representations of farms ...
3
votes
5answers
1k views

How to vary the transparency of symbols within a single layer in ArcMap?

I have a polygon layer which I am drawing in ArcMap using a graduated color symbology: Is it possible to vary the transparency between the classes, so that the transparency tapers off with the ...
3
votes
4answers
2k views

Cannot fix QGIS after upgrade to Ubuntu 13.04 Raring

I have following problem. After upgrade to 13.04 I had problem with PyQGIS mentioned here. I followed almost all advices described there, finally removed QGIS (had 1.8 Lisboa) and added the Ubuntugis ...
3
votes
1answer
2k views

How do I find vector line bearing in QGIS or GRASS?

How can one extract the bearings from a set of lines in a vector file? I'm trying to find the bearings of several straight vector line segments (simplified contour lines, actually) and can't figure ...
7
votes
1answer
645 views

How to reopen hidden panels in print composer?

I unfortunately deleted the menu (Qgis 1.8.0) in print composer (settings for labels etc) . Now I am wondering how to display it again? The menu is gone in all my projects and I could not find a ...

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