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

learn more… | top users | synonyms (1)

6
votes
1answer
1k views

How to create a style file for QGIS from a plain text file?

Using QGIS 1.7. I have a plain text file, which lists 115 rgb values against a map code for a geological map. Viz.: $ head gsv1Msymbology.txt MAPCODE RED GREEN BLUE Oc 143 255 255 WAT 255 255 255 ...
5
votes
1answer
2k views

Calculating distance to points in QGIS

Is there a way of calculating the distance to the nearest points in QGIS? In ArcGIS there is a function called Euclidean Distance, which can take an input vector or raster, and generate a raster of ...
3
votes
1answer
114 views

How to horizontally align irregularly shaped point symbol to vector layer in QGIS?

Fairly new to QGIS and searching a method to graphically align my point symbols in the direction of the vector. The symbol represents a water valve in an irregular shape in close proximity to a vector ...
3
votes
1answer
1k 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 ...
3
votes
2answers
1k 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
3
votes
1answer
756 views

Get a pixel value

How can i do this operation: I want to get a pixel value fro the satellite image (Landat, GeoTIFF, 7 bands) using qgis-python. What operators should i use? (for example in qgis's Python Console) ...
3
votes
2answers
2k views

Workflow for creating line features between two coordinate pairs in QGIS

I have a table of stream reaches with xy coordinates for their respective tops and bottoms. I'd like to convert the table to a feature, using the xy coordinates as the endpoints of the line. Any ...
2
votes
2answers
758 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 ...
14
votes
1answer
2k views

Can QGIS preserve layers when exporting to PDF?

In ArcMap, when you export data to PDF it preserves the layering within the PDF so that you can turn on/off individual map layers (within the PDF itself). When I export from QGIS to PDF, I don't ...
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 ...
9
votes
3answers
4k views

How to determine the centroid of polygons?

I have a polygon vector and I want to quickly attain the centroid of this polygon for insertion in a text document. I am working with QGIS. I searched through other questions and although some are ...
8
votes
2answers
358 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 ...
6
votes
1answer
526 views

Where are the Expression-based Labeling options in QGIS?

I have imported a layer into my map to show the location of towns/cities. However I had to set graduated styling so that only cities over a certain population show. I now want to label the ones that ...
6
votes
2answers
3k views

How to move labels in QGIS?

I'm trying to manually move labels but having some trouble. I'm trying to move the labels while in edit mode. I've added fields for x coordinate (all null), y coordinate (all null), rotation (all =0), ...
5
votes
3answers
272 views

How to visually sort the order of Points with QGIS, GDAL, …?

The following Points layer is the basis of a rendering in a Android application. Android allows to draw a shape from the provided points. I cannot use LineStrings. However, the order of points ...
5
votes
1answer
547 views

How do I clip OSM basemap with a polygon?

I've created a map in qgis 2.0. The map uses the OpenLayers plug-in to add the OSM layer as a basemap. I would like to restrict the basemap to be visible only inside a given polygon defined in a ...
5
votes
4answers
3k views

Quantum GIS and ECW images?

How might I enable Quantum GIS to read ECW imagery? At the moment I'm mostly concerned about this on Ubuntu 10.4 amd64, but I also use WinXP & Win7.
4
votes
2answers
686 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. # ...
4
votes
2answers
342 views

Setting rendering order of line layers in QGIS

I have a dataset where different road types are in separate layers, i.e. motorways, primary roads and secondary roads. In turn, each layer is subdivided by embedded codes into different sub-types - 4 ...
3
votes
4answers
15k 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!
3
votes
1answer
1k views

QGIS 2.0.1 Runtime error and crash at Add Delimited Text Layer plugin

I just installed Dufour on my Windows 7 Lenovo ThinkCentre desktop. When I open 2.0.1 I get this error window: And when I try to add the 'Add Delimited Text Layer' plugin I get this message: ...
3
votes
2answers
910 views

How to install shapely for python 2.6 (Mac) NOT 2.7?

I'm trying to use Polygonizer plugin inside QGIS, but it needs Shapely to work. I've installed Shapely (pip install Shapely) but that's for python 2.7. QGIS works with python 2.6 (on Snow Leopard) and ...
1
vote
1answer
201 views

How to go with…somewhat complex geological maps in QGIS?

Just a follow-up to this question QGIS: Line to polygon conversion. Not sure do i have to continue there itself... We are currently digitizing a geological map...which has 36 features in total. Some ...
1
vote
1answer
270 views

How to produce multiple maps with same layout for different layers' extents?

I have an area which is divided into several zones the borders of which I have defined as separate layers. The layers are defined by sql queries on a postgis table of line segments joined with a ...
1
vote
3answers
1k views

How to create points based on the distance and bearing from a survey point?

I am plotting witness tree data to calculate pre-settlement tree density. I have a shapefile with points along section lines (square miles) at each half mile. I am making another table that contains ...
1
vote
1answer
522 views

Delineate polygonal catchment areas from a raster using open-source GIS

I'm 90% sure this basic question has been asked before but looking through the other posts I simply do not see a useful answer. I need to calculate polygonal(vector) catchment areas from a raster ...
33
votes
8answers
12k views

QGIS and gvSIG comparison

Many debutant GIS users are asking me which one is better QGIS or gvSIG. Since I use Qgis and I don't have any experience in gvSIG, I aways say that both are very nice softwares and the chose is a ...
25
votes
2answers
7k views

How to style beautiful road maps with QGIS?

I am trying to design a beautiful map using Qgis. As I'm a software developer not a designer, I was hoping that this will be easy, but it isn't! There is a similar question here Qgis tutorials and ...
25
votes
3answers
27k views

How to add Basemaps from Google or Bing in QGIS?

Like ArcGIS Desktop has the option of using basemaps from ArcGIS online, does QGIS have any such options?
24
votes
3answers
4k 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 ...
22
votes
5answers
4k views

How to identify clusters in vector point data?

I have a vector dataset of rural broadband data-points (how fast, etc.) and I'd like to explore if there are clusters of points with similar characteristics, and to plot polygons encompassing them. ...
6
votes
2answers
2k views

How to calculate Network Service Areas in QGIS?

Is there any way in QGIS to apply service area buffers e.g if I have a point on a map I wish to show the service coverage of 1 mile, 2 mile, 3 mile, breaks using the road network?
14
votes
6answers
4k views

A SQL console in QGIS

I know QGIS comes with its field calculator, which is not bad. It also comes with ftools which permits several operations on geometry and attributes. But we often need more control and I haven't seen ...
11
votes
4answers
8k views

Feature comparison between QGIS and ArcGIS for Desktop [closed]

I am learning to use QGIS and ArcGIS for Desktop but I cannot find the differences between them. What are the differences between the capabilities of QGIS and ArcGIS for Desktop?
8
votes
1answer
2k views

How to add labels outside of features?

I'm trying to achieve this kind of labeling using QGIS. Apparently, it doesn't seem to be easily supported. Would you have an idea for a workaround ? I managed to have circled text using ...
11
votes
4answers
2k views

How to place elevation numbers on contours with uphill orientation and position?

I want to orient my elevation labels uphill. Is that possible? I'm currently using the labeling tool from QGIS (not that one in layer settings). I want the labels curved and uphill oriented (and I ...
11
votes
1answer
2k views

How do I build a custom form for entering attributes in QGIS

I've done this many times in ArcGIS and ArcPad but I don't even know where to start building a custom form for data entry in QGIS. I would like to do this for field operations--QGIS would make a good ...
9
votes
1answer
6k 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, ...
8
votes
1answer
200 views

How to automatically populate fields instantly?

I am looking to create an attribute table where the first field is a drop-down menu (I have achieved this by using the 'value map' edit widget), but I'm struggling to find a method for the next part; ...
6
votes
1answer
11k 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 ...
11
votes
2answers
3k views

How to create a new empty vector layer programmatically?

I am new to python and QGIS. I have looked at a few tutorials of python scripts for QGIS. All of them create new vector and raster layers with some existing data source. eg. shapefile or geotiff or ...
8
votes
1answer
4k views

Create a csv with geometry as WKT in QGIS (and choosing the field delimiter)

Is there a way to choose the field delimiter when exporting to CSV with geometry as wkt in QGIS? I have a shapefile with donut holes and I'd like to export it as a CSV. It's for a partner whose DB ...
4
votes
4answers
2k views

What is the projection of WGS84 in GIS software?

WGS84 is a reference ellipsoid that determines coordinates of every point on Earth using latitude, longitude and height about the its surface. This ellipsoid is often used as a base to make maps. ...
13
votes
1answer
687 views

How to setup QGIS Master and Stable in parallel on one Linux system?

I mainly use the QGis Master (nightly build) for my Debian Linux and I'm quite happy with it. But for educational and demonstration purposes, I now have to work with the Stable(1.8) version. How can ...
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 ...
4
votes
1answer
495 views

Is there a purge function to remove layers from a qgs file which are not present in the Layers pane?

I have some QGIS projects that I've been using for long time, adding and removing layers, updating reference to deleted or moved files etc. Opening with a text editor the qgs file I see that it ...
4
votes
2answers
2k views

Adding a hotlink to an attribute field in QGIS

How to add hotlink to QGIS? I saw this but had some problem. I want to open network location like \\fileserver\filefolder\file1.excel but it ends with error. Edit: The network location is stored ...
12
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
5answers
3k views

Get Raster Values from a Polygon Overlay in Opensource GIS Solutions

I have two layers. A polygon-shape-layer with many tiles and a raster-layer containing CORINE 2006 land cover with many categories in a colourmap. I want to obtain for each polygon in the shapelayer a ...
9
votes
2answers
11k views

How to enable projection transformation in QGIS

My QGIS project has two layers, one layer is retrieved by Google layer plugin which fetches the static Google map image whose CRS is +proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +a=6378137 +b=6378137 ...