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

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11
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3answers
315 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
5answers
3k views

How can I map a matrix of origins and destinations in QGIS?

I have a central point on a map, and I have other points in a separate layer (the location of a venue, and the origin cities of the venue visitors). Is there a plugin which would generate output ...
11
votes
5answers
4k views

Is it possible to connect to ArcSDE using QuantumGIS?

Is anyone aware of any plugins, or any other way to connect and view data from an ArcSDE database in Quantum GIS desktop?
11
votes
1answer
504 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
654 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
552 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
votes
2answers
1k views

How to create contiguous area cartograms in QGIS or R?

Here is what I want to achieve (on the right): I am looking for a tool or a method to transform a shapefile (with QGIS or R) into this form. And please be aware: It's not just clipping a hexagonal ...
11
votes
1answer
316 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
4answers
2k views

How to connect lines in a network?

I have a shapefile of lines and another of polygons. When two or more lines intersect a polygon they should be connected (snapped), but sometimes during manual digitization this doesn't occur. I need ...
11
votes
1answer
749 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
2answers
253 views

How to sort by multiple fields at the same time?

Is it possible to sort multiple fields at the same time in QGIS? For example, I'd like to sort a table by state name, and then within each state, sort by county name. This would be the same as the ...
11
votes
0answers
307 views

How to query OSM for all beaches facing west? - QGIS preferred

I want to identify all beaches on this planet (or a given subset of it) that are facing westwards (+/- 20-30 degrees). My idea is to use OSM as the data source. Extracting all polygons that have the ...
11
votes
1answer
401 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
8answers
18k views

How to import a DWG into a QGIS project?

I have a lot of DWG files like base map, and water and wastewater network. I am lookin for the principal steps to import my files into my QGIS project.
10
votes
5answers
563 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
2answers
6k views

How to reproject a vector layer in QGIS?

I have some shape file which is in UTM. I wanted them to convert to Decimal Degrees in QGIS. Thanks.
10
votes
6answers
1k views

How do I make a heat or Choropleth map that uses polygons in QGis?

I've been playing around with the heatmap plugin for QGIS and I am wondering if it is possible to make heatmap with using a similar plugin/tool that uses polygons as well as points? I would like to ...
10
votes
2answers
2k views

Running QGis from flash drive

How can I setup a portable QGis to run from a flash drive / USB-Stick? In the userguide for QGis 1.7 Wroclaw there is only mentioned the option of "--configpath". But to me it is not clear how to deal ...
10
votes
3answers
7k views

How to import coordinate data from excel into QGIS?

I have an excel file containing data collected over many years as latitude and longitude coordinates for archaeological sites - how can I import it into QGIS as a new layer?
10
votes
4answers
8k views

Is there a SVG symbol library for qgis?

Im currently using default simple symbol capabilities or dingbat fonts for point objects. Is there maybe a SVG symbol library for qgis that is a bit more extensive than that which is included? I've ...
10
votes
3answers
2k views

shp2kml license expired, looking for free solution

So I work for a small African non-profit. I do all the GIS and data work. Most of the layers I create, I convert to kml layers so my boss can then use them quickly and easily in Google Earth. But now ...
10
votes
3answers
2k views

How to snap lines to points automatically?

I have two vector shapefiles: One file is points representing manholes and the other is a polyline file representing pipes leading to and from the manholes. I need to snap the lines within a ...
10
votes
3answers
2k views

Are there open-source alternatives to ArcGIS online that can be hosted on my own server?

I know this might be too broad topic. But I am looking for web-GIS portal similar to ArcGIS online that is self-installable (configurable) to be hosted in my private server. The main features should ...
10
votes
2answers
3k 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. ...
10
votes
2answers
420 views

Is there an automatic function in QGIS to package all shapefiles in a project for transferability?

In my project, I use a lot of geodata from different directories. Now I want to give the QGIS project to a colleague (eg on a CD). Is it possible to copy the shapes from different directories ...
10
votes
4answers
4k views

How to create equidistant points in QGIS?

I am trying to create points (new layer) at specific distance along the road (existing layer) in QGIS. This gives solution for ArcGIS. How to achieve this in QGIS? This one explains how to create ...
10
votes
1answer
5k views

How do I calculate the latitude and longitude of points using QGIS?

I'm trying to figure out how to calculate the lat/long of points using the QGIS field calculator. Is there an easy way to do this? I saw a previous related question, but it deals with a more advanced ...
10
votes
1answer
390 views

Is there a way to add system date in print composer?

Is there a way in the Print Composer of QGIS to create a label that will automatically update the date (systems date) instead of having a label that you have to manually have to update?
10
votes
2answers
9k views

How to Add OSM Layer to QGIS

How can i add OSM layer in QGIS? The help says there is an OSM plugin i can use. But i don't see it the list of plugins. Or maybe there is a WMS URL for OSM i can use? QGIS version ...
10
votes
5answers
2k views

How to identify duplicate attributes in a field?

I have a point shapefile with thousand of points. It has an ID code field that supposed to be unique. Every now and then the data entry clerk wrongly type the id creating duplicates.Right now I'm ...
10
votes
2answers
1k views

How to buffer a line with different distances for left/right sides

How can I buffer a line in QGIS using one attribute for the left side of the line and one attribute for the right side of the line? I am trying to buffer a river with its bank width, which is ...
10
votes
1answer
534 views

How to convert fake donut holes in polygons to real ones?

I have this problem where I have to import shapefiles into our system which must be geometrically valid, but the software that everyone uses to produce them seems to output files where every polygon ...
10
votes
2answers
2k 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 ...
10
votes
1answer
784 views

Is it possible to take automatically a “screenshot” of my selected feature in QGIS using Python?

I am implementing a tool which allows the user to create a profile of a feature (in my case urban parcels). Is it possible to automatically take a screenshot of this feature (displayed in a QGIS ...
10
votes
1answer
857 views

Is there a way to access QGIS plugins in Python?

Is there a way to access QGIS plugins in Python? I'd like to write a script to do some geoprocessing, and I'd like to use the clip, regular points and convex hull tools in fTools, as well as the Road ...
10
votes
1answer
5k views

Merging adjacent polygons in shapefile that has been split at tile boundaries?

I'm currently using building data from the Ordnance Survey Vectormap District and I've noticed that a lot of building polygons are split in 2 because of the way the OS split up the shapefile. This is ...
10
votes
1answer
536 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.
10
votes
2answers
420 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 ...
10
votes
1answer
285 views

Open-source software for managing terabytes of different formats of geospatial data?

I have a problem that I am sure many GIS Teams or Departments have which is how to find, keep track of and manage multiple different datasets from multiple sources. I have read the responses from a ...
10
votes
3answers
516 views

Contours: Interrupt contour lines beneath a elevation number

Is there a way to interrupt a contour line beneath a elevation number? Thanks!
10
votes
1answer
544 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- ...
10
votes
2answers
2k views

How do you display related records in QGIS?

Coming from an esri background I have always used relationship classes in a gdb to display records related to a feature. Eg. Relate 1 survey point to many documents, photos etc. Does any one know how ...
10
votes
2answers
682 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 ...
10
votes
1answer
312 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 ...
9
votes
2answers
5k views

How to add Direction and Distance to attribute table?

anyone who can help. i just want to add direction (Bearing: i.e N 25 35 E) and Distance (Length: 125 meters) as my new field in polyline/line data. is there a plug-in to generate these fields? i tried ...
9
votes
6answers
7k views

How to join lines in QGIS?

In QGIS, I have two lines. The endpoints are near each other, but not quite aligned. I'd like to turn the two lines into one, with the two endpoints merged into midpoints. The closest I've been able ...
9
votes
4answers
9k views

How to change a CSV layer attribute value from text to number?

I read in a CSV file for linking to a .shp file. All the variables that are just numbers came in as text. How do I change the text variables to numeric in QGIS?
9
votes
4answers
4k views

Tutorial on how to model flooding using data from gauging stations along rivers in QGIS?

Can someone please direct me to a tutorial where I can learn more about how to model flooding using data from gauging stations along rivers using QGIS?
9
votes
2answers
398 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 ...
9
votes
2answers
9k views

How can I join several raster files using QGIS?

I'm new to QGIS. How can I combine multiple raster layers into one layer? The raster images are of different areas with very little overlap. The goal is to bring numerous town plats into one project. ...