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

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27
votes
3answers
11k 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 ...
7
votes
2answers
7k views

Rotating a vector layer in QGIS with qgsAffine (or other method)?

I would like to rotate a set of vector points in QGIS an arbitrary number of degrees around a central point (or arbitrary point). This is similar to a recent question about creating a regular grid; ...
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
15k 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 ...
8
votes
5answers
7k 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
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
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
5k 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, ...
6
votes
4answers
6k views

Qgis - Is there a way to split a polygon layer with a line layer?

I am drawing administrative regions that have boundaries follow streets in another layer. As these streets are pretty long with many vertices, I don't want to re-trace them. I am looking for a way to ...
5
votes
2answers
3k views

How to create multiline labels in QGIS?

How can I apply Multiline label option in the label property.Name field contains a lengthy name. I want to wrap it. How can I do it? please help me. My QGIS version is 1.8
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
835 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. ...
4
votes
2answers
12k 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
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 ...
2
votes
2answers
317 views

How can I access `processing` with Python?

I want to access the explode lines function in Python outside of QGIS from a standalone script. What module do I have to load in order to use it? How can I access processing? from qgis.core import * ...
7
votes
1answer
655 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 ...
4
votes
3answers
25k views

How to fix Runtime Error R6034: An application has made an attempt to load th C runtime library incorrectly?

I just downloaded QGIS 2.0 and everytime I open it I get this error message window popping up: Does anyone know what this means or how I might be able to fix it? Thanks!
2
votes
1answer
1k views

How to evaluate raster calculator expressions from the console?

How can I execute from the console an expression that should be used with the raster calculator? I'm searching for something like this: qgis.someRasterCalcClass.evaluate("boh@1 + boh@2", ...
25
votes
4answers
7k views

How to smooth a DEM?

I have a SRTM DEM and I want to create a shaded relief from it. I created the shaded relief in GRASS and the result is very nice, but a little rough becouse the area is near flat and the DEM is 90m in ...
11
votes
1answer
7k 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 ...
16
votes
2answers
9k views

How to run a simple python script for QGIS from outside (e.g. Sublime Text)?

I would like to run a few small and simple python scripts for QGIS (Mac) from "outside" of QGIS. With outside I mean in this context, either the normal os command line (terminal.app) or even better, ...
20
votes
3answers
4k views

How can I switch line direction in QGIS?

Something that is hopefully pretty easy. I would like to be able to swap the direction of a polyline/line in QGIS. I made a custom tool to do this in MapInfo a couple of years ago, however I can't ...
15
votes
4answers
6k views

How to join attributes from nearest point in QGIS?

I have two layers with points, call them A and B, each with different attributes. For each point in A I want to join all the attributes from the nearest point in B. Ideally this would also include ...
19
votes
4answers
21k views

How do I load OSM vector data in QGIS 2.x?

In QGIS 1.8 I used the openstreetmap plugin to request data from the server, or open a .osm XML file, which produced 3 layers (polygons, polylines and points) in QGIS. This was great (give or take the ...
14
votes
3answers
4k 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 ...
15
votes
3answers
4k views

Visual Impact Assessment in QGIS or GRASS

Is it possible using QGIS or GRASS to perform a Zone of Visual Impact assessment? E.g. where can a 100m high structure be seen at a viewing height of 1.8m within 30km, taking into account elevation ...
7
votes
4answers
4k views

How to split a vector in equal smaller parts in QGIS or similar?

i want to divide a shapefile with many tiles into a lot of smaller tiles. I am searching for a smart solution, because manual edits are out of questions Anyone can help or know a nice function?
19
votes
4answers
10k views

Joining non-spatial CSV file to spatial data (shapefile) using QGIS?

I have a CSV file which has postcode data in a field, but it is non-spatial e.g. no Easting and Northing. I have a shapefile with postcode in a field and some additional data. I want to join the ...
10
votes
1answer
3k views

OpenLayers Plugin Error: latitude or longitude exceeded limits

I'm aware the 'traceback' OpenLayers plugin error has been dealt with before, so apologies for raising the issue once again. Unfortunately for me, the solutions posted were way over my head, e.g. ...
6
votes
1answer
4k 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. ...
15
votes
1answer
2k views

Voronoi polygons that run out to infinity

I have been working on implementing the voronoi.py script (Bill Simon's translation of Steve Fortune's code). According to the QGIS link it is basically the same code that I am working with, but the ...
11
votes
3answers
4k views

How to programatically check for a mouse click in QGIS

I want to know how to check for a mouse click in QGIS. I am trying to write a python plugin and want to provide functionality similar to the "Select Single Feature" tool that already exists in QGIS. ...
10
votes
1answer
1k 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 ...
8
votes
1answer
2k views

Sort layers in QGIS table of contents?

When I load a bunch of layers into QGIS from PostGIS, they seem to load in reverse alphabetical order. Is there any tools or plugins that allow you to quickly sort the QGIS TOC in a different order? ...
6
votes
1answer
3k views

Shortest distance from point to line (big dataset)

What is the best method to calculate the distance from the nearest road for a series of address points in QGIS, having a very big dataset? (QGIS 2.0.1, Win XP) I read the answers to previous similar ...
5
votes
1answer
2k views

How to perform Ordinary Kriging in SAGA via QGIS SEXTANTE Plug-in?

I'm trying to learn how to apply the kriging analysis in QGIS using the SEXTANTE plug-in and SAGA tools. It appears that I have my SEXTANTE and SAGA folders configured properly according to the user ...
3
votes
5answers
3k views

Unable to install ECW support on lubuntu 14.04

I try unsuccessfully to install the ECW support (mainly to use ECW file in QGIS 2.2). We attempt to follow and adapt the howto provided by makina-corpus. My first supprise was the repository ...
3
votes
2answers
2k views

Simple automated way to split all lines in layer at vertices using QGIS?

I want to automatically split all lines in a QGIS layer at their vertices (like this). I've done a google search and found this article, which is quite close but the workflow is complicated. Because ...
2
votes
3answers
1k views

Data-defined Styles in QGIS

I have downloaded a shapefile of bedrock geology. I need it to be displayed as it should be with the style applied. The supplier will no give me a qml. but i have noticed in the .dbf file the Cyan ...
10
votes
1answer
6k views

Understanding QGIS buffer tool units?

I have been trying to figure this out for a couple weeks now and have had no luck getting the buffer tool to accept anything but degrees as units of measure. I have found lots of stuff saying the ...
9
votes
2answers
9k views

How to create a new layer from overlap between two layers?

I'm new to desktop GIS, and will try to ask while lacking the proper terms from the GIS lingo: If QGIS was like Photoshop I would like to make a selection from one layer, and then match that ...
6
votes
1answer
3k views

How can I transform a polygon to a linestring in QGIS?

I have a polygon, imported from a shapefile in QGIS. I would like transform it to a linestring instead so I can save it as a GPX file later. How can I transform a polygon to a linestring in QGIS?
8
votes
2answers
678 views

Where did the polygons go after projecting a map in QGIS?

I'm fairly new at GIS know-how, but I've run into a problem with a projection of a world map. I have a shapefile of all countries I downloaded from Natural Earth. After projecting it into a ...
5
votes
2answers
2k views

Cannot see OpenLayers under Plugin in QGIS 2.4

Although I have installed the OpenLayers plugin, I cannot see it in the list when I click on Plugins. Does anyone else have this issue?
4
votes
1answer
1k views

How to style a layer from console?

I am new to the QGIS python console. I am trying to load a raster layer from the console, set the crs and a specific style from a qml file. layerPath = os.path.join(raster_dir,raster_name) fileInfo = ...
21
votes
5answers
4k views

Is there any model builder in QGIS or other open source GIS?

Like the ModelBuilder of ArcGIS for Desktop to run simultaneous geoprocessing tools, is there any model builder available in QGIS or any other open source GIS software?
16
votes
9answers
26k views

How to install QGIS on Ubuntu 12.04?

Has anyone had any luck with getting QGIS working on Ubuntu 12.04? I have tried the stable and unstable versions and with not luck. I also get the following: "Some packages could not be installed. ...
7
votes
1answer
17k views

QGIS - Change unit of measure from degrees to meters

I am running QGIS 1.7.0 on windows, and I donwloaded a shapefile of census block group boundaries from TIGER. This file appears to be in the WGS 84 coordinate system, and when I open it in QGIS the ...
14
votes
3answers
965 views

Is there an automatic function in QGIS to package all files 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 ...