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

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12
votes
2answers
7k 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, ...
12
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 ...
23
votes
5answers
2k views

How to generalize a polygon file and maintain topology in QGIS?

I have a polygon Shapefile, which I need to generalize. How can I generalize the poligons and ensure that there are no topological errors like "slivers". I already tried: Vector -> Geometry Tools ...
6
votes
2answers
2k views

What are valid values for “data defined” labeling settings?

I'm using QGIS 1.8. I'd like to customize label features on an existing shapefile using the new label engine and it's "data defined settings" option. I'd like to know what the attribute table field ...
9
votes
3answers
4k views

How to create polygons with straight lines and right angles in QGIS?

I am running QGIS 1.7.0 on Mac OS X 10.6.8. When creating a polygon, how do I do it so that the lines are straight (90, 0 degrees, etc.) and when I create corners they can be right angles? For ...
8
votes
1answer
266 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; ...
7
votes
1answer
3k views

How to fill gaps in SLC-Off Landsat 7 ETM+ Images with QGIS?

Explanation of the problem: On 31 May 2003 the Landsat 7 Enhanced Thematic Mapper (ETM+) sensor had a failure of the Scan Line Corrector (SLC). Since that time all Landsat ETM+ images have had ...
7
votes
1answer
5k views

Is there are QGIS plugin to allow the 3d visualisation of geological borehole data similar to the functionality of Target for ArcGIS?

I'm very new to QGIS, I have started using it as my new company is not willing to pay for ArcGIS and Target at this stage so I'm hoping QGIS can substitute not just in the interim but for good. What ...
6
votes
2answers
201 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 ...
5
votes
2answers
3k views

How to install QGIS on Centos 6?

I'm new on this; I really tried a lot before ask.. but nothing works. I did all that the qgis page says. Install ELGIS. after that i investigate and tried diferents comands.. but nothing works..the ...
16
votes
8answers
17k views

Can QGIS open KMZ files?

I know I can add KML files once I have unzipped the KMZ files, but is there a way to open KMZ files directly? When I try to open a kmz file on QGIS 1.8.0 on Windows XP, through the all files filter, ...
12
votes
5answers
5k 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?
10
votes
2answers
3k 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
4answers
4k views

Is there a Rotate Tool in QGIS?

I can see the move tool. But coming across versions, i did not see any Rotate tool in Quantum GIS. As a hardcore feature editor myself, i have found it rather difficult. Am i missing something ...
11
votes
4answers
11k 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
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 ...
8
votes
1answer
900 views

Is there a QGIS equivalent of the erase tool in ArcGIS?

Is there a QGIS equivalent of the Erase tool in ArcGIS for Desktop?
8
votes
2answers
942 views

Are there any tools / plugins to develop mapbooks using QGIS?

Are there any tools / plugins to develop mapbooks using QGIS?
7
votes
4answers
6k views

How to calculate raster statistics for polygons?

how can I calculate sums, averages etc of raster-points (multi-band) per polygon of a vector-layer. I was told that this is called "zonal statistics". I tried that with QGIS first. There is a way to ...
3
votes
2answers
1k views

Batch Dissolve Polygons based on Attributes in QGIS or FWTools

I was wondering if anyone can help with batching a dissolve. I have a few hundred polygon shapefiles that I want to dissolve based on an attribute. I would like to do this in QGIS or FWTools. Any ...
12
votes
7answers
8k views

How do I create a shapefile showing footprints of Rasters?

I have around 1,000 satellite images in tiff format, and I want to create a shapefile which will serve as an index to the rasters. This is something similar to a raster catalog, but I do not want to ...
10
votes
2answers
4k views

Is it possible to create Thiessen polygons around nodes in QGIS?

Is it possible to create Thiessen polygons around nodes in QGIS? e.g. http://en.wikipedia.org/wiki/Voronoi_diagram
7
votes
3answers
5k views

How to access QGIS Plugin Repositories from behind a proxy?

I have been trying to teach myself QGIS by using this forum and others to help. Most of my questions can be answered by downloading plugins that are available through 3rd party repositories but for ...
7
votes
1answer
9k views

Adding Layerfiles (.lyr) to QGIS?

At college we use ArcGIS Desktop 10, but that does not function on my Mac so I have QGIS there instead. I want to do my exercises with QGIS, but we use .lyr files with ArcGIS Desktop, and they are ...
6
votes
1answer
2k 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?
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
2answers
2k views

How to link to external files with relative path in QGIS actions?

Objective: I have point layers with attributes contain paths to external files (visio, autocad dwg...). I want to put them all in one folder together with the project file, compress the folder into a ...
5
votes
2answers
2k 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
731 views

QGIS affine - form of equation

I am at the mercy of a govt authority who have provided utility information in a cad format with a 0,0 origin and a nonsense grid. About a dozen files, the grid and origin are entirely arbitrary. To ...
5
votes
1answer
3k 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 ...
4
votes
1answer
895 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
1answer
152 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
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
1answer
515 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 ...
2
votes
1answer
1k views

QGIS Python version

I have brewed python 2.7.3 onto my Mac (Lion), and installed shapely via pip install shapely. The Polygonizer plugin, however, does not find the shapely library. I see when QGIS loads a Python ...
0
votes
1answer
1k views

Create a hyperlink to a pdf file in the attribute table [duplicate]

I want to add a hyperlink to a pdf file into the attribute table of a vector layer. I already read the documentation about evis and the answered questions about this here. It didn't seem difficult, ...
15
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
3answers
6k 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 ...
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 ...
6
votes
1answer
810 views

How to calculate te area between contour lines on a DEM with QGIS 1.8?

Does anyone know how to calculate the area in km² for each altitudinal band (between 100 and 200, 200 and 300...) based on a DEM? I added the contour lines with a distance of 100 metres but could not ...
6
votes
1answer
558 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
1k views

Raster generalization - buffers in rasters, expand pixels?

Is it possible to create buffers for pixels of raster files? Actually I need to expand the pixels classified as 1 (in white in the figure) with a spatial range of 1 or 2 pixels, in order to perform ...
6
votes
2answers
4k 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
350 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
794 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
1k 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
4answers
19k 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!
4
votes
2answers
847 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
435 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 ...