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

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20 views

EasyCustomLabel in QGIS do not resize the labels

I use EasyCustomLabel to move some labels, but if I try to change the dimensions of the chars I cannot view any changes, both in the work and in the printing sheets. I use QGIS 2.6.1.
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13 views

How to fill a symbolLayer with a custom texture?

I have this code : pLayer is a QgsVectorLayer * QgsFeatureRendererV2 * lrenderer = pLayer->rendererV2(); QList<QgsSymbolV2 *> lSymbols = lrenderer->symbols(); QgsSymbolLayerV2 * ...
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1answer
61 views

How to create soil-type maps using QGIS

I am trying to create a soil-type map of an area from point data using QGIS. I tried interpolating the data, since soil is continuous. I did this by allocating a number to each point type and then ...
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0answers
23 views

How to react to network events

I am in the process of writing a Plugin which should react to some data (XML-Format) sent via a socket connection. Since I have never worked with IPC in terms of python before and my knowledge of IPC ...
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20 views

How to display attributes of features intersecting the Atlas feature in a Print Composer label?

Is it possible to edit labels with python or an expression? I have an atlas layer and a shape with countries. the atlas layer has several features and each feature intersects with several countries. ...
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19 views

QGIS: calculate slope of line-segments

Using QGIS, I'd like to achieve the same as in question calculate-slope-of-street-segments. I have a shapefile with lines (rivers) and a DEM. So I suppose the best way is somehow like this: 1 - ...
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0answers
44 views

QGIS spatial join - join all features, not just one

I'm trying to do a spatial join of a feature on a polygon layer (p1) that intersects with two features of another polygon layer (p2)) via QGIS. What I want: get the attributes of both features of p2 ...
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0answers
38 views

QGIS Forms - Limit list values based on a previous field

Looking for assistance to set up appropriate configuration to enable drop-down lists values to be filtered based on a previous value. Basically, I have a 3-tiered categorisation structure to one of ...
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1answer
18 views

looking for documentation about exploiiting OSM file with c++ API

My application is written in QT4.6, i use the C++ API of QGIS 2.8.2 i had to read and display OpenStreetMap in my canvas in my application so, i am looking for some documentation or tutorial for ...
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1answer
29 views

Performing linear regression of NDVI raster time-series using QGIS?

How can I perform linear regression of NDVI raster time-series images using QGIS? I have NDVI images for seven years to perform vegetation trend analysis. Each year has two to four different image ...
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42 views

How to cut big shapefile into several smaller shapefiles?

I'm converting my shapefiles to gpx files to use them in garmin gps, but if the shapefile is too big, I lose data in the conversion. I get a gpx with holes in and I cannot work with it in the field. ...
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13 views

Capturing line version 2.10

I'm a beginner (as in complete noob) user with version 2.10. I'm trying to digitise some rivers from a raster layer but can't find the "Capture Line" tool which the tutorials and resources show as ...
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16 views

How to export shapefiles and other attributes to KML using QGIS?

Is it possible to include all the attributes in the table of a shapefile when exporting it from QGIS to KML? I want to view all other data inside my table in Google Earth.
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1answer
13 views

Problem trying to build a stand-alone QGIS application with Unbuntu Trusty system

I'm currently reading the "Building Mapping Applications with QGIS" Book and I'm stumped when I try to set my paths in Ubuntu. The first command works fine: export PYTHONPATH=~/usr/share/qgis/python/ ...
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1answer
50 views

Calculate slope of line based off of point layer

I have a line feature class that needs to have its slope included as a field. I have a point layer that contains points and their elevations for the start and end of the line segments. How can I ...
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29 views

How can I convert Decimal to DMS for QGIS reprojection?

I have the following Lat/Long which I converted to DMS using the following calculator: Decimal DMS -96.2 96 12 0 -95.13 95 7 47.9994 29.3 29 18 0 29.98 29 58 55.1994 ...
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0answers
35 views

how to orthogonalize building outlines

I'm looking for a way to orthogonalize building outlines which I've extracted from a high-res DEM. I'm using the FOSS GIS stack (QGIS, GRASS, SAGA, PostgrSQL, PostGIS) and can code in Python (or ...
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1answer
21 views

pgrouting: function driving_distance does not exist

I tried to run driving distance function but got error. function driving_distance(unknown, integer, integer, boolean, boolean) does not exist LINE 1: SELECT * FROM driving_distance(' ...
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0answers
29 views

How do I make atlas with same pages but different layer sets?

I have a project in QGIS with multiple layers that I have to render separately. E.g. parks and distances to them (their buffers), travel time isochrons (interpolation with colors), density heatmap, ...
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1answer
39 views

Calculating Distance and Time on a network without the use of ArcGIS Network Analyst

I'm trying to calculate a distance and time for walking commuters (about 30,000 records) on a street network (NYC Lion). I have a starting and ending address for each record that have been geocoded. ...
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2answers
31 views

QGIS Processing Scripts Shared Code

I'm on a Windows 7 machine with QGIS 2.8 installed via OSGeo4W. I'm developing several processing scripts that make use of a few common pieces of code. Rather than maintain the code in each individual ...
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2answers
49 views

Critical facility pipe connections in python

I'm trying to find a way to determine pipeline connections located downstream a critical facility and score how far those connections are from the facility. Is there a way to accomplish the above ...
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2answers
32 views

How to measure the sum of the areas of each class in QGIS?

The project has a layer with several groups of polygons with different weights. Each group is associated to a weight. How can I get the sum of the area of each group?
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11 views

how can i change property of a symbol using qgis 2.8 c++ api

i have an application written in QT 4.6, and use the C++ API of QGIS the application will display the data of the s57 file in a MapCanvas i managed to read the file but how can i , for a specific ...
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1answer
34 views

Finding the date of acquisition of Google maps in QGIS

How do i find the date of acquisition of the Google map on QGIS? Please help.
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2answers
52 views

Standard color mapping for NDVI?

I am currently generating some NDVI imagery using QGIS 2.8.2 and there are a multitude of possible color map scales that can be applied to the imagery. I was wondering if there was a preferred or ...
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1answer
26 views

Create primary and foreign key on Spatialite

I try to create a database on spatialite (for various reason, I can't use PostGis). I need to link a table to another one using a foreign key. The problem with spatialite is that it is not possible to ...
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0answers
16 views

Lizmap server - tool location - big data

Hy, I have installed qgis server + lizmap on windows. I use the tool from lizmap plugion "location by layer", it's well except when i used a big layer with 60 000 lines. I have no error in apache ...
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20 views

SSL-Authentication failure

i try to include a wms-map into my current project. When i try to connect qgis 2.4. gives the failure-output: Attributes-request denied - failure in the SSL-protocol procedure. ArcMap 10.2 says: ...
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1answer
40 views

How to get the coordinates inside the polygon using python

I have a polygon and using this code snippet we can get the coordinates boundary of the polygon. canvas = qgis.utils.iface.mapCanvas() aLayer = canvas.currentLayer() coord = ...
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0answers
19 views

Nearest neighbour / spatial join with attribute condition

I have 2 point format datasets I wish to schematically join (manholes & gullies). I am content that I can join them by nearest proximity alone using e.g. NNJoin plugin. What I would like to do ...
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1answer
55 views

Does anyone know a way to do a supervised classification on a google maps image to show only hedgerows?

I would like to then use the hedgerows by bringing it into QGIS as a layer. I need to know what software to use and the method to make such a layer? I would like to use a google earth image in Grass ...
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1answer
36 views

Processing modeler: how to dissolve a vector layer and sum the attributes

I have a complex workflow prepared in the processing modeler, but I'm missing one step to link all the model. As said, I need to dissolve a polyline vector in a single line vector that has as ...
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2answers
63 views

Suitable Raster processing methods to extract field boundaries from images

I'm trying to extract field boundaries and features from a lot of aerial images of agricultural land - and avoid digitizing these features manually. I've managed to get a crude raster file of the ...
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1answer
24 views

Running LAStools on QGIS 2.8

To be honest I'm not sure how to run LAStools from within QGIS 2.8. I'm trying to learn by experimentation. QGIS shows all the LAStools in the toolbox If I double click on a LAStool in the toolbox I ...
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1answer
59 views

Using GDAL library in QGIS plugin?

i've been working on my project to create QGIS plugin for raster analysis purpose. It will be easier if we use gdal library. Are we able to use gdal library to develop QGIS plugin? If so, how do ...
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0answers
11 views

How to pass a token value to QGIS processing modeler?

There are various places in the Processing modeler where I would like to pass the value of a variable. We're iterating through a bunch of features in an input layer. After the processing, we will have ...
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0answers
11 views

Couldn't load plugin sextantelwgeomprovider, QGIS 2.0.1 on Ubuntu 14.04.2

I'm getting this error message when I start QGIS Couldn't load plugin sextantelwgeomprovider due an error when calling its classFactory() method Traceback (most recent call last): File ...
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1answer
37 views

What's difference between Topology and Check Validity in QGIS?

I would like to know what the difference is between the Topology Checker and Check Validity tools? Is there anyone who knows of a good document or tutorial that explains functions of these tools? ...
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0answers
29 views

Dependent Comboboxes in QGIS 2.8.2

I´m setting up an database for an archaeological project with PSQL. There I have a field "material" connected with a table "materials" containing things like metal, stone, etc. In a third table I have ...
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1answer
32 views

How can I create a polygon from points and assign it a color in QGIS using python?

I want to create a new vector layer, containing a polygon from a set of given points, and giving it a color.
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0answers
31 views

Is it possible to perform spatial join in PostGIS and keep all features?

I am attempting to create an employment change map using a hex grid. I have individual establishment data as points with attached employment figures. When I ran the spatial join using the postGIS ...
3
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1answer
25 views

QGIS Convert bathymetry shapefile from fillable to strokeable

In Java I would like to stroke the bathymetry depth lines instead of filling the area. I'm starting with the Natural Earth Bathymetric Data: ...
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65 views

Grass 7 no longer works via the Processing Toolbox in QGIS

When I try to execute a Grass 7 algorithm via the Processing Toolbox in QGIS 2.10, 2.8.2 or 2.8.1, I get the following error: Missing dependency. This algorithm cannot be run :-( QGIS ...
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0answers
21 views

How do I count the number of vector lines that pass though a given raster cell?

I am working on a project (currently in GRASS7 though I'm not against exporting to Arc or R or other software if necessary) where I am generating thousands of shortest cost paths (using the r.walk and ...
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0answers
22 views

Minidump Error Messages With Large Dataset

I'm using QGIS 2.8 on a system running Windows 8.1 (x64) with 12GB of RAM. I am attempting to run analyses of a very large database (.gdb format, 7.17GB). In attempting to run the "Join attributes by ...
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2answers
64 views

Pipeline connectivity

I'm trying to find a way to determine pipeline connections located downstream a critical facility and score how far those connections are from the facility. Any Thoughts?
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0answers
18 views

How to insert composer file name and path in QGIS print composer

Can you automatically insert the print composer name and project file path as text in print composers in QGIS (v2.8) without copying and pasting the path? e.g. equivalent functionality to inserting ...
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2answers
28 views

QGIS 2.2 is very slow while saving the edited layers

I am using QGIS 2.2 64 bit in windows 7 system. I have an issue while saving the layers after editing. Its taking more time to save my edits. Some times it's working fine but very often i am getting ...
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1answer
35 views

QGIS Composer: Force loading of all tiles on export

I face the problem that not all tiles are loaded on a map export via the QGIS composer. This happens randomly with all kinds of tile servers provided by the openlayers-plugin. Any hint how I can ...