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

learn more… | top users | synonyms (1)

2
votes
1answer
34 views

Calculating distances across land only

I am trying to do point to point distances in QGIS but I have points to point distances that are being calculated across oceans. Given people don't generally fly around cities does anyone know a way ...
2
votes
1answer
91 views

How to calculate the 3D length of line segment in QGIS?

I've been looking through all of the GRASS commands in the QGIS 2.10 processing toolbox and it seems like one of these must be able to do this but I haven't found one yet. There is 'v.sample' which ...
2
votes
1answer
83 views

How to scale SVG symbols which are not label background on zoom level in QGIS

I need to scale the SVG symbols on zoom level. @Underdarks answer in the posted question did not help me thus I can't set the SVG symbols as label background for I have labels which should not be ...
2
votes
1answer
69 views

QGIS: Finding electric network loops

With QGIS, how can we analyse an electrical network to find loops? Using Python is not a problem, however there is not a solution in the QGIS Python API. The QgsGraphAnalyzer has dijkstra and ...
2
votes
1answer
60 views

How to break a closed line when intersect with polygon

I have a number of polygons (in lines shape) which represent the new condition of an area and a numder of polygons (in polygon shape) which represent the old condition of the same area. How can I ...
2
votes
1answer
108 views

Why does Points2One complain “Can't make a polyline out of one points.”?

I know this question has been asked before .I am trying to connect pairs of points by lines using the Points2One tool in QGIS. I have created the data and exported it as shape file. The data looks ...
2
votes
1answer
108 views

Is it possible to animate a cartogram with FOSS GIS?

I was wondering if anyone knows of any FOSS tools to animate cartograms? By this, I mean 'tweening' between the geographic shapefile and the cartogram version of a shapefile. This means gradually ...
2
votes
2answers
39 views

Mean coordinate issue with multipart polygons

I've been using Mean Coordinates in QGIS to find weighted mean centers based on different attributes for the counties in a singular state of the US. However I have come across a problem in which the ...
2
votes
1answer
36 views

How do I create a bivariate map legend (3x3 cells) in QGIS?

I would like to create a bivariate map, and need to create a 2 dimensional legend to accompany it. How do I create a bivariate map legend (3x3 cells) in QGIS?
2
votes
1answer
79 views

ST_Union based on attribute

I have a road network of center lines of MultiLinestrings.They have nodes at every intersection. I try to understand how I can merge roads together that have the same category as attribute (There are ...
2
votes
2answers
147 views

Where is the QGIS API action for “deselect”?

Where is the QGIS action for the “deselect” toolbutton in the 'Attributes" toolbar? I do not see this action in the QgisInterface class or do not recognize it by name. Is it missing from iface? I'd ...
2
votes
2answers
113 views

PyQGIS Use of predefined color ramps

I´m trying to apply one of predefined color ramps to a categorized field in a vector layer. To do this, I'm using the code below suggested by Irssvt in another post. However, I cant´t see the result ...
2
votes
1answer
78 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. ...
2
votes
2answers
128 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?
2
votes
1answer
405 views

QGIS2WEB Plugin (openLayer3) for QGIS not exporting raster images

I am using the QGIS2WEB plugin for QGIS. I have added vector features as well as a raster image (.tif or .ecw) format. When I try to export the webmap, all the layers are visible expect the rasters. ...
2
votes
2answers
72 views

What CRS is the USGS Global Land Cover Characteristics Data Base?

I have trouble bringing land cover data from the USGS into a "decent" coordinate system. I obtained an .img file of the "Global Land Cover Characteristics Data Base Version 2.0" from ...
2
votes
1answer
99 views

Processing algorithm fails from Python script

I'm trying to write a Python script performing a geoalgorithm. What is surprising me is the following: I first test the algorithm by QGIS (2.8) interface. In my case, the GRASS interpolator ...
2
votes
1answer
81 views

The QGIS atlas defined with pyqgis and a QPT template exports the same maps

I need to generate an atlas for each feature from a layer for reporting. There will be created a few maps. The centre of each map must be focused on each feature. In this task I use a predefined QPT ...
2
votes
2answers
181 views

GDAL/QGIS broken Ubuntu 14.04

I think I've managed to bust GDAL after (I think) installing Grass7. I had previously built GDAL (1.10) from source with a bunch of additional drivers. When installing Grass7 GDAL 1.11 was installed. ...
2
votes
1answer
57 views

how can I get the majority (dominant) class of a raster to an area (polygon) using qgis?

I have a vector layer with many basic units of planning (zones), a raster layer with three classes of geology and other raster layer of geomorphology with five classes. How can I update the ...
2
votes
1answer
89 views

QGIS crashing/failing when dissolving multiple shapefiles in a Python loop

I am using QGIS 2.10 (but I've also tried 2.8) to loop through all the shapefiles in a folder (those ending in .shp) and perform a dissolve function on each of them. However, when I run the following ...
2
votes
1answer
43 views

QGIS: Labels shifting to different locations after I save from the attribute table

I just started working with QGIS, and I'm having a problem with my labels. I have figured out how to manually move labels for the points on my map (thanks to this forum!)--I have edited the attribute ...
2
votes
1answer
151 views

QGIS: raster image georeference and overlay

I've created a grid and points in QGIS which I used to survey. Using a test image at the moment and I'm trying to fit this image as an overlay within a boundary. When I insert the image it has a white ...
2
votes
1answer
105 views

Can I use TIFF files for zonal statistics in QGIS or ARCGIS?

I am completing a remote sensing paper and am doing most of the work in PCI Geomatica, where I have 2 separate files. One from running a texture analysis algorithm containing 6 band layers from a ...
2
votes
1answer
36 views

QGIS Heatmap values change when imported into ArcMap?

I am creating a heatmap layer from QGIS and importing the TIFF into ArcMap. When I import the file into ArcMap I notice that values are different. For example the max value in QGIS is 8.92454, but ...
2
votes
2answers
608 views

Attempt to install QGIS 2.8 on Ubuntu 15.04 installs old version instead

I previously had installed QGIS 2.8 with the GRASS plugin on Ubuntu 14.04. Through a chain of events I ended up having to do a clean install of Ubuntu 15.04, and am attempting to re-install QGIS 2.8. ...
2
votes
1answer
69 views

QGIS feature subsets are incompatible with table joins. Bug?

When using QGIS 2.8.2, I am unable join a table to a layer that has a feature subset (Layer Properties > General > Feature Subset). For example, creating a feature subset on a layer prior to joining ...
2
votes
1answer
110 views

How to conduct an inner join with QGIS?

My QGIS (2.8.2) joins always result in an outer join. How do I create an inner join with QGIS?
2
votes
1answer
228 views

How to create a plugin GUI for QGIS 2.8.2?

I create a pluging with the pluging builder in Qgis 2.8.2. I went to the folder of my pluging : C:\OSGeo4W64\apps\qgis\python\plugins\yu in order to visualize al the files that the pluging builder ...
2
votes
3answers
94 views

Strange coordinate system [closed]

Here's an extract of a feature from the web that I converted to geojson using qgis. However, the coordinates are not standard are at all and when trying to actually preview it on the web it fails, ...
2
votes
2answers
269 views

How to create a line between a point and nearest neighbour using python (template included)

I have 2 shapefiles - one is a series of points, the other is a polyline. I want to draw a straight line between each point to the nearest point on the polyline. This question has already been asked ...
2
votes
1answer
45 views

What's the syntax to skip optional saga:catchmentareaparallel parameters?

In PyQGis, I want to use saga:catchmentareaparallel algorithm, in the parameters there is an optional arguments, and I don't want to use them, what is the value should i put on the argument? i try to ...
2
votes
1answer
81 views

How to define map extents based on a feature's geometry?

There is a polygon geometry in my QGIS project which represents the extents of my map. Does anybody know how to use the data defined override to get the X/Y min and X/Y max coordinates of the polygon ...
2
votes
1answer
199 views

How to interpolate raster to get finer resolution?

I am working with precipitation raster layer. It happens the raster data to be in a resolution of 0.25 degrees grid. How could I interpolate those pixels to have a better resolution, say, a resolution ...
2
votes
1answer
189 views

How to open a “.sos” file without crashing QGIS?

I am trying to open a ".sos" file in QGIS. I have QGIS installed using OSGeo4W and added the gdal-sosi package. This should do the trick. But QGIS just shuts down when I try to open the file. It ...
2
votes
1answer
38 views

How can I convert climatic text data to raster in QGIS and ArcGIS?

I have been provided with text (*txt) formatted, tabular climatic data. How can I convert climatic text data to raster in QGIS and ArcGIS? In addition to tabular data, the following information is ...
2
votes
2answers
106 views

Automating selection and sliver elimination using QGIS

At the moment I do this manually: open a shape file open the attribute table use "select features using an expression" - the expression is "area" < 200 then I use vector/geoprocessing ...
2
votes
1answer
126 views

How to get mean geographic direction of a polygon in QGIS?

I have a raster height model and would like to calculate the horizontal geographic direction (north, east, etc. - orientation) of each cell, then calculate then the mean value of all these cells in ...
2
votes
1answer
279 views

Qt/C++ Hello World application with QGIS not compiled: qgsconfig.h not found

I am a Qt/C++ developer. I have to create a GUI application (Qt/C++) with GIS maps. I'm trying to do that using QGIS. I'm working in Linux Ubuntu with Qt Creator 2.4.1 (based on Qt 4.8.0). I did the ...
2
votes
1answer
147 views

How to interpolate line Z from sparse attribute values

I have a series of end-to-end connected 3d lines which I'd like to add elevation values for all vertices on the lines which are currently null or 0. How to accomplish this? In the following image ...
2
votes
1answer
57 views

Extracting area from DEM Raster?

After applying constraints to the DEM I polygonised the raster (using GRASS r.to.vect.area) The result is shown below with a lot of vector with resolution = [30 * 30] Is there any solution to make ...
2
votes
2answers
1k views

Can QGIS export Geospatial PDF for Avenza PDF map app?

Since QGIS uses GDAL, does any map exported as a PDF become a Geospatial PDF? I am hoping to import maps from QGIS into the Avenza PDF Map app on my phone. Previous posts mentioned exporting as ...
2
votes
2answers
241 views

How to get path for layers listed in a combobox?

I want to get the path of a layer in my plugin, in the console it works fine but in my plugin it gives me the error AttributeError: 'NoneType' object has no attribute 'dataProvider' def run(self): ...
2
votes
1answer
142 views

merge two DEMs of different resolutions? [duplicate]

I have two DEMs, the first one is in 30 meters of résolution and the second: 5 meters, and will like if there is a possibility of merging them to extend the area where I do my research?
2
votes
1answer
107 views

QGIS plugin problem, can't reach objects in a Qt-based Stacked Widget

I am creating a plugin for QGIS but am having trouble with the Qt components. I have used Plugin Builder and Qt designer to create all necessary files for the plugin. I want to use a QStackedWidget ...
2
votes
1answer
39 views

Is there a solution to glitches when deleting features from Shapefiles on network drives?

We are a small GIS department of 4 folks working with a shape file composed of points. We have local installs (C:) of QGIS 2.8.1 on our workstations, which run Windows 7 x64. The shape file in ...
2
votes
1answer
98 views

QGIS reprojecting .ecw file in EPSG:23032

I opened the .ecw file with qgis but I found that the ortophoto is 340 mt northern and 150 mt eastern the topographic map. How can I move the ecw?
2
votes
2answers
227 views

QGIS error when importing .asc LIDAR data

First let me say that I am novice in GIS department. As archaeologist I had only some courses 8 years back when i was still studying. Now, the problem: When I try to import .asc as raster layer I ...
2
votes
1answer
320 views

How can QGIS Field Calculator sum values from a spatially joined table?

Can the Field Calculater be used to sum values from a related table via a Spatial Join? I have two vector polygon layers A and B, each with a numerical column VALUES. I want to update VALUES in ...
2
votes
1answer
51 views

Two different colours in label

Is it possible to have label in QGis 2.8 two different colours? For example Field1 in red colour and Field2 in blue (Field1 || ‘ ’ || Field2).