QGIS is a cross-platform GIS application licensed under the GNU General Public License.

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11
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2answers
3k views

How to get FGDB support in GDAL 1.9 without compiling?

I was hoping that I could use the 'master' (nightly-build) version of QGIS to get fgdb support without compiliing (I'm not a developer and frankly have wasted days of productive time trying to get ...
11
votes
2answers
2k views

What is the standard Mercator projection?

I'm using QGIS in order to re-project a shapefile I have into "Mercator" so that something like protoviz understands my co-ordinates. Protoviz tells me "Mercator" ...
11
votes
2answers
215 views

Identify points in a shapefile that have no other point within x km with QGIS

This is probably a naive question but I am struggling as a new user to QGIS. I have a very large shapefile (275,000 points, but can break this into about 10 subregions if necessary for faster ...
11
votes
2answers
4k views

How do I check which version of GDAL I have and how many?

I have installed in my computer the following software: PosgresSQL 9.3.2.3 PostGIS 2.1.1.1 QGIS 2.0.1 Dufour (this one installed through the OSGeo4w package) QGIS 1.7.0 Wroclaw As far as I know ...
11
votes
2answers
571 views

How to perform repetitive tasks in QGIS?

I am trying to do a treatment on many feature files, so I would like to automate it. In fact, I have one shapefile with the spatial distribution of some species, and one with vegetation type. I ...
11
votes
3answers
408 views

How to improve drawn shapes in Quantum-GIS?

I have a polygon-shape in qgis-1.7.0 and want to fix overlays and gaps between the edges of adjacent polygons. See image below. Is there any automated way to do this in quantum-gis? Or any other ...
11
votes
1answer
1k views

Is there a way to add a “current user” label to the print composer?

Is there a way to add a current user label to the print composer in QGIS. I thought there might be something similar to the $CURRENT_DATE format available. This would be in a windows environment.
11
votes
1answer
7k views

How to write standalone Python scripts using QGIS?

I've been learning how to use the Python Console in QGIS using references from qgisworkshop.org. I'm familiar with writing standalone scripts in ArcGIS and want to learn how to do the same with QGIS. ...
11
votes
1answer
669 views

Nearest Neighbor Grouped Selection in QGIS

OK - so I have an interesting problem I am trying to solve. I have a list containing over 100,000 points in lat/long format which I have imported into qgis. Now, what I am trying to do here is group ...
11
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2answers
1k views

Is there a detailed description on the .qgs file structure somewhere?

Is there a detailed description on the .qgs file structure somewhere? I checked here: http://mrcc.com/qgis.dtd ("The requested URL /qgis.dtd was not found on this server.") and here- ...
11
votes
1answer
672 views

QGis raster terrain analysis - The curvature filter puzzles me

I am a french Master student at university Grenoble INP, and during my master project I have worked on DEM (raster) terrain analysis. Thus, I have read the source code of several QGis-1.7.4 raster ...
11
votes
1answer
1k views

Method to shade or overlay a raster map to reflect time of day and ambient light

I have a daytime raster of my study area. I have 20+ counters in the study area that count "stuff" with a timestamp. Using PyEphem I determined the type of ambient light for each collected data ...
11
votes
1answer
930 views

Can PostGIS and QGIS provide dependable multi-user editing?

After considering a few options, I'm trying to give my 15-20 QGIS 2.2 users the ability to concurrently view/edit one or two basic point PostGIS layers, largest one has just 16,000 records. I've ...
11
votes
1answer
673 views

How to associate polygons with the nearest point on a point layer? (Or … how do I assign a postal area to a salesman?)

I have a polygon layer of postal code areas and I want to use them to create sales territories based on where our sales people are based. So I assume that I need to work out for each of the polygons ...
11
votes
2answers
801 views

How to build a minimum convex hull crossing the 180 degrees line?

I've been building convex hulls for species that inhabit the Indo-Pacific (~ from 20 to -65 degrees of longitude). The problem I've encountered is that for the species that can be found on both sides ...
11
votes
1answer
590 views

Is there a simple way to sort layers alphabetically in QGIS?

I am working on a big GIS project and not being able to sort the items in the Layers panel is giving me hard time. I can have up to 250 layers in the Layers panel. I have a special naming scheme for ...
11
votes
1answer
873 views

Snap line layer to network in QGIS or PostGIS

I have GPS data I've taken of bus routes, and now I'd like to snap it to my road network. Both layers are line layers in a PostGIS DB. I'd like to use either QGIS or PostGIS, but if I have to go with ...
11
votes
1answer
834 views

PyQGIS file lock release

I was wondering what triggers the release of file locks in pyQGIS? I am trying to delete a few data sources (used temporarily) by calling QgsVectorFileWriter.deleteShapeFile, but I have to quit QGIS ...
11
votes
1answer
479 views

Is it possible to edit layers from a FGDB - File Geodatabse in QGIS?

I think I've found the answer (you can't edit FGDB's) but there seem to be few reports around that it is possible to edit FGDB files in QGIS. Can anyone advise if it's possible to setup QGIS ...
11
votes
2answers
2k views

How can I improve my Georeferencing results?

Background This is my second question related to georeferencing naked raster maps in order to re-visualize them on different coordinate systems and in conjunction with other data layers. The previous ...
11
votes
1answer
1k views

How to create text labels with background boxes?

I'm trying to create some custom labels for point features in a QGIS point vector layer, and I want to write a python plugin to do it. We need our labels to be presented with color tinted rectangles ...
10
votes
3answers
303 views

Field calculator: Calculate sum of parts of column, based on another column

I would like to calculate the sum of values in one column, based on values in another column. To illustrate my question I uploaded the picture below. The second column consists of zipcodes, the third ...
10
votes
6answers
6k views

How to get “.GDB” Esri File Geodatabase in QGIS for MAC OSX 10.6?

I understand there are programs like OSGeo4W that allow windows users to work with File Geodatabases, but is there something similar for Mac OSX?
10
votes
5answers
611 views

Database versus Files for Solo Developer

I'm just getting started in GIS and am interested in using it to create maps of mountain biking trails in my area and nearby. I've been learning QGIS and have made enough progress to generate a decent ...
10
votes
3answers
353 views

How to set transparency per polygon in a shapfile in QGIS?

How to set transparency per polygon in a shapfile in QGIS? For example: a polygon with field "value" = 1 should be fully transparent whereas field with field "value" = 0.4 should have a 40% ...
10
votes
1answer
2k views

Is it possible to show our custom message in QGIS Status bar using python?

Is there any way to show our custom message in Qgis Status bar using python? Just like in arcgis IApplication.statusbar.message(0) = "Please wait..." like that is there any option to show progressbar ...
10
votes
2answers
6k views

Resources on using R in QGIS for R users?

This is a very basic question, but I'm having a heck of a time figuring it out because so much of the QGIS documentation is oriented toward use of the GUI. I want to be able to run R scripts in QGIS, ...
10
votes
5answers
2k views

Multicriteria Analysis : how to?

I have to do a multi-criteria analysis to answer the question : "which is the best lot to develop". A few of the criterias are : distance of the nearest bus stop (point layer with bus stops) ...
10
votes
2answers
4k views

How to cite QGIS in publication?

What is the best way to cite QGIS in a formal publication? I mean, what text should be included in the References / Literature Cited section of a paper or report. I'm also specifically referring to ...
10
votes
6answers
2k views

QGIS users - What plugins do you consider to be essential?

The title says it all - vector, raster, geoprocessing plugins?
10
votes
2answers
812 views

Can I add an ArcToolbox tool to QGIS?

I have been using a publicly available tool in ArcGIS called SPreAD-GIS. It is a series of python scripts that are "implemented as an ArcGIS toolbox" (with tbx file). I am new to QGIS. Is there a ...
10
votes
5answers
14k views

Can QGIS read an ODBC connection?

I have a co-worker who manages a large MS Access database that contains X & Y fields for various locations he tracks. We have previously exported the data to CSV and used the QGIS Delimited Text ...
10
votes
2answers
4k views

Derive WGS84 Longitude & Latitude from British Northings & Eastings

I'm looking for a fairly simple way to append columns with WGS84 longitude and latitude to a table containing northings and eastings. The source data is Ordnance Survey's CodePoint Open, which I is ...
10
votes
3answers
9k views

How to control Image Output Settings in QGIS?

I am exporting a QGIS map to an image format. I would like to have control over the output settings of the image (dpi), as currently it is only exporting the images at 96 dpi. Does anyone know if this ...
10
votes
1answer
533 views

Adding new menu item to QGIS Desktop app?

I need to add new menu item to the top level menu of QGIS Desktop (2.7.0); I.e. it shall be on same level as "Project", "Edit", "View", "Layer" etc. As far as I know there is pretty nice way how hide ...
10
votes
4answers
4k views

How to avoid creating corrupt Shapefiles during Editing?

I have one of my GIS technicians digitizing some lines in QGIS in shapefile format. I don't know how he did it (and neither does he), but somehow the shapefile became corrupt. It was creating random ...
10
votes
3answers
2k views

Cannot run standalone QGIS script

I've been trying, along with this post, to run a script in OSGeo4w Shell, outside of QGIS. But I get the following error: ImportError: No module named qgis.core I have also read the following ...
10
votes
3answers
1k views

How can I parallelise embarrassingly parallel GIS operations in QGIS python?

A common requirement in GIS is to apply a processing tool to a number of files or apply a process for a number of features in one file to another file. Much of these operations are embarrassingly ...
10
votes
2answers
2k views

Why are heatmaps on qgis 2.8.1 produced in the wrong CRS?

I noticed that the heatmap calculation on the new upgrade version of qgis is given the raster map without any coordinate system. Have you got the same problem?
10
votes
1answer
193 views

How to save python session in QGIS?

After running a lot of scripts in QGIS' python console, I have more than 10 dictionaries and lists, and I need these for further analysis. Is there a way to save python session, with all these ...
10
votes
3answers
848 views

QGIS Categorized Style: Rearranging values so that it doesn't go 57,58,59,6,60,61

I have a a column of data that I'm trying to display in the Categorized Style but when QGIS orders the values it ranks them, for example, 57, 58, 59, 6, 60, 61, 62.... Is there a way to rank them in ...
10
votes
4answers
4k views

Finding centrelines from polygons in QGIS?

I was wondering if there is a way to create centre lines from polygons in QGIS? I have a polygon layer, but ideally need the centrelines as a separate file.
10
votes
5answers
14k views

How to join multiple records to single feature?

apologies for what I'm guessing is a really easy problem to solve. GIS user, not programmer here. I'm trying to create a join/relate in QGIS where I have a shapefile of buildings and to that I would ...
10
votes
1answer
1k views

Import GRASS and SAGA modules to python script

I'm new at this. I am "building" a python plugin for qgis and I want to import modules from GRASS and SAGA but I don't understand how to do it. The plugin I want to import is Kriging interpolation ...
10
votes
1answer
914 views

How to address the new “Task-Completed” QgsMessageBar in Python?

I am really amazed what huge steps the QGIS development has taken in the last months. The new iconset, the improved Print composer and many more changes to be seen in QGIS 2.0 are really awesome! ...
10
votes
1answer
14k views

How to enable “snapping” in Quantum-GIS while drawing polygons?

I tried to draw polygons in qgis-1.7.0 and I somehow can't find or failed to find the "snapping" option. I'm used to ArcGIS-10.0 where you have some snapping options, like placing points of polygons ...
10
votes
1answer
10k views

How does snapping in QGIS work?

I have read a number of posts and tutorials, even the QGIS manual on snapping. I set the snapping options under settings>snapping options; selecting the two layers that I would like snapping on, ...
10
votes
1answer
1k views

How to render a table with mixed geometry types in QGIS?

I created a table with geometry type "GEOMETRY" AND inserted data of point, line and polygon type. My question is how to show this spatial data Qgis not supporting for geometry type "GEOMETRY".
10
votes
3answers
450 views

From polygon to continuous measure of diversity?

First of all; I have tried to find a similar question, without success. Maybe it's because I'm quite new to GIS and I don't really know what exactly I'm looking for. If someone points me to a similar ...
10
votes
3answers
2k views

How to create a Hillshade model with multicolor “alà Imhof”?

I would like to make a Hillshade-Model with multicolor "alà Imhof". That means, I dont want a "usual" gray hillshade, I would like to use grey-blue and grey-violett from different sun directions. ...