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

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1answer
80 views

QGIS create raster from cadastre (property lot data) polygon

I have a cadastre (property lots) polygon dataset of a region. Have used rule-base style in QGIS to show different groups of properties in the dataset classified based on their property lot size (ie. ...
1
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2answers
2k views

Importing DWF files into QGIS

I regularly receive files from a service authority in DWF format, which shows the location of their assets in there area. I note that there is no option to have the data in an alternate format as it ...
1
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1answer
73 views

How to crop a vector shapefile according to raster?

I am trying to clip a vector shapefile- points according to a DEM in QGIS. I used GDAL function and polygonized the DEM. Then I ran the Vector-Geoprocessing tools-clip in order to crop the vector data ...
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0answers
179 views

QGIS Grass Processing toolbox

I'm trying to use some of the GRASS tools from the processing toolbox in QGIS. I get the following Python error: An error has occured while executing Python code: Traceback (most recent call last): ...
3
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1answer
122 views

How to combine historic OS sheets in order to create density maps of historic streets

I really need some advice on creating historical street maps using GIS software (I have access to QGIS and Diva). Basically, I want to upload a number of historic OS sheets, which I have downloaded ...
2
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1answer
328 views

Delete duplicate polygon nodes with PostGIS

I'm trying to delete duplicate nodes from a shapefile with QGIS, but after running the tool to delete it, nothing happens and shows the same errors. I thought that maybe importing to postgis could be ...
2
votes
2answers
704 views

Open Raster stored in ESRI V10.0 Geodatabase in QGIS V2.4

Is there a way to open a raster that is stored in ESRI V10.0 Geodatabase in QGIS V2.4. I can open the vector layer, but there does not seems to be a way to open a raster.
8
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1answer
184 views

Can you use wildcards for column headers in Field Calculator?

I know you can use wildcards for fields like so (in the Field Calculator): case when "column" ILIKE '%example%' then 1 else 0 end Can you do something similar for the column headers themselves? I ...
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4answers
515 views

QGIS “Delete ring” no longer works

I have QGIS 2.4.0. Until just today, the "Delete ring" feature worked just fine. Now it no longer works at all. I rebooted and even reinstalled QGIS 2.4, and it didn't fix the problem. But I also ...
3
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0answers
93 views

Option for 360 degree movie embedded in Open Source GIS software?

Is there any Open Source GIS software available to embed 360 degree movies with the map? For a COTS example, there is the Active Link Vision (ALV) extension for ArcGIS from IWANE.
3
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2answers
714 views

Remove Holes Existing Within a Single Polygon for a specific area in Qgis

I have a shapefile that consists of a single polygon. I have gaps within the polygon that needs to be eliminated, but only the ones that are less than 200m2. I tried different ways but none of them ...
2
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0answers
21 views

Processing Toolbox, avoid using empty layer

I have a process (on the processing Toolbox) I need to reproject and merge two layers (result of previous operations). Sometimes, one of these layers will be empty, in that case it is not necessary to ...
4
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1answer
477 views

How to extract DEM (Digital Elevation Model) from 3D model

How can I extract a Digital Elevation Model from a 3D model of a building, made with SketchUp, using Blender,qgis or any other software?
2
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0answers
315 views

Configure the Search Function in QGIS Web Client

I have set up the QGIS Web Client but do not know how to get the search function to work. I read the instructions in the guide but can't really understand what it is saying: 6.1.2. PHP ...
5
votes
2answers
394 views

Merge uniquely named point shapefiles in 50,000 different folders into a single layer

I have point shapefiles in 50,000 different folders (each shapefile file name is unique) - about 33,400 shapefiles (not all folders will have a point shapefile). I like to open the point shapefile in ...
2
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0answers
118 views

QGIS doesn't recognize GRASS commands

When I try to use GRASS commands in QGIS, I get the following error message: Missing dependency.This algorithm cannot be run :-( This algorithm requires GRASS to be run. Unfortunately, it seems ...
3
votes
2answers
377 views

Correlation between a raster and a point dataset

I have an interpolated surface (in raster form) with temperature values and I also have the measurements of temperature in certain locations that belong to the same region (with the raster). I want to ...
1
vote
1answer
113 views

Programmatically export a Qgis project

I have a QGis project that I programmatically modify using the Python xml.etree library. Now, I would like to know if it is possible to add few lines to my script in order to export the modified ...
2
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0answers
202 views

How to populate the geometry_columns table

I have a SQL Server table of vector data (containing latitude, longitude, UComp and VComp columns), that I am trying to add as a layer to QGIS. Here is a sample of the data in the SQL Server data ...
4
votes
1answer
331 views

Can ArcGIS ModelBuilder be exported to Python and run in QGIS?

Is it possible to construct a geoalgorithm on the ArcMap modelbuilder, export this entire algorithm to python syntax (without having ANY knowledge of python) and then import this algorithm to QGIS and ...
2
votes
0answers
42 views

Can't run SAGA or GRASS commands from QGIS processing toolbox [duplicate]

I can't run anything from this toolbox. I tried running SAGA dissolve polygons and got the following error : Oooops! The following output layers could not be open Dissolved Polygons: ...
2
votes
1answer
94 views

Extract all raster cells outside a polygon

How does one perform the very simple task of extracting all raster cell values outside a polygon? I've been looking through QGIS for hours with no solution to this simple problem.
2
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0answers
190 views

Is MapProxy and Google's Static Maps API a possible alternative to the QGIS Openlayers plugin?

I've been looking for an alternative to the openlayers plugin as a means of adding imagery basemaps to QGIS. The plugin is great but there's a bug when exporting basemaps via QGIS map composer that ...
3
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1answer
79 views

No get more option in QGIS

I have recently installed QGIS and trying to work with it but I don't see this option "Get More" at all. As suggested by some previous source, I also checked whether I am behind a proxy but that isn't ...
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0answers
93 views

How to avoid random transparent pixels in georeferenced grayscale raster images?

I'm in the process of georeferencing some old black and white aerial pictures from 1990 in QGIS 2.4. So far, this is business as usual, no problems. Of course I get the usual black triangles, because ...
2
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0answers
330 views

Problem loading output layer QGIS

Every time I run operations with temporary file output from the graphical modeler, I get the following error message: Oooops! The following output layers could not be open CLIP: ...
3
votes
1answer
116 views

Why GRASS 7.0.0 can't create a table while importing shapefiles from QGIS?

I use GRASS7.0.0Beta1 and QGIS 2.4.0 on Windows8. With v.in.ogr, when I import a shapefile, I get the error message "Unable to create table". When I put the option of not importing the table, the ...
3
votes
1answer
1k views

Save selection option in QGIS 2.4.0

I am using QGIS 2.4.0 Chugiak version. Is there an option to save selected features from a shapefile? I couldn't find such an option in this version. I am using stand alone application. Is this option ...
3
votes
1answer
57 views

Show a single value related to a whole layer in QGIS

I'm developing a maximum flow plugin for QGIS. I would like to show a calculation result (i.e., the maximum flow) on the map. The result is not a property of a single feature. It is a property of a ...
2
votes
0answers
231 views

pyQGIS 2.0: Sending signal when identify button is pressed via gui

I have a question regarding the qgis identify tool for version 2.0. I would like to know if it's possible to send a signal when the actionIdentify is triggered by the user via the gui. I'm trying to ...
3
votes
0answers
71 views

Is it possible in QGIS print composer to include a numeric scale in an html box?

For work I always have to create a table with my name, project name, date etc. into my map layouts. I also need to include the scale like "1:150000" in that table. So far I am solving that by ...
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6answers
2k views

How to clean/edit GPX (tracks) files recorded from GPS device?

During a long trip, I have recorded tracks of my journey with the GPS of my smartphone. I have ended up with about 30 GPX datafiles. Now that I am back, I am trying to draw a map of this trip. I ...
3
votes
2answers
122 views

Google layers not matching

I'm working in a project with whole Europe data. I'm working with WGS84 (4326), and sometimes I overlay my polygons with Google maps layer (in QGIS) to see some details. When I do this, I have to ...
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1answer
78 views

R.Mapcalc giving only blank maps as result

No matter what function I put in the r.mapcalc in the GRASS GUI I get a blank map full of null values. I even tried DEM+0 (I can see my DEM) and this also yielded a blank map.
3
votes
0answers
125 views

IS it possible to run GRASS commands in the QGIS graphical modeler?

I have a geoalgorithm set up in the graphical modeler and everything runs except for the GRASS commands. It is really frustrating because when I execute these commands on their own they work just fine ...
5
votes
2answers
3k 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?
3
votes
1answer
762 views

SAGA raster calculator, ifelse command syntax problem?

I am trying to get the saga raster calculator in QGIS to spit out all values of a raster that are inferior to 10, and make all other values zero. I think the syntax is correct but I keep getting the ...
1
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2answers
425 views

Does QGIS support dynamic display?

I'm a new developer of QGIS using C++. I am working on a project which needs to display dynamic maps/layers(just like GPS, but it is not GPS, however it should display data alike GPS data - dynamic ...
3
votes
0answers
469 views

QGIS API - Print Composer Template produces empty map?

I have a print composer template which I'm trying to populate with different subset queries from a CSV-derived vector layer using the Python API. However, all the output PDFs contain everything except ...
3
votes
1answer
283 views

Get default values from PostGIS DB in QGIS 2.4 editor

One of my postgis tables tables automatically includes the nextval(xxx) in the edit feature form in qgis(and I think will also update ids of multiple features automatically). The other seems to have ...
0
votes
0answers
32 views

Graphical Modeler Equivalent in Arcmap? [duplicate]

Is there a similar interface as the QGIS Graphical Modeler in Arcmap for geoalgorithm development? If so can one develop a sequence in Arcmap and open it in QGIS? I would prefer using an 'Arcmap ...
1
vote
0answers
83 views

Multiply Rasters with Scalar Numbers as Input in QGIS Modeler

I built a little model in the QGIS modelbuilder which uses the raster calculator with the command gt(a,threshold) I need to run the model with varying thresholds from 2 to 30 so it would be ...
3
votes
0answers
76 views

Merge shapefiles to one tool not working?

When using the data management tool "Merge shapefiles to one" in QGIS why is it copying one of my shapefiles instead of merging the two together as it should?
4
votes
0answers
310 views

Preparing Huff model with data to use in QGIS? [closed]

I'm trying to find out about the notion of potential of acessibility using the methods of Huff. I´m using QGIS, with point data (with the variables that I would like to use) and polygons for Europe ...
1
vote
0answers
56 views

How to share styles between layers in QGIS

Is it possible to share one style between different layers in QGIS? Now if I apply the same style from *.qml or use the same style from Style Manager for different layers then in *.qgs project file ...
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0answers
85 views

Categorized style hiding map

I am having an issue with the style properties of my map. I imported the US Zip Code Tabulation Area map from a government website, and in a separate excel file I have a list of people connected to ...
1
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1answer
116 views

Unable to save to in Geojson format with the correct projection

I have a shape file (Polygon) in Qgis that I wish to save in Geojson in order to display it with the mapbox javascript api. Original projection is in POSGAR 97 My issue is that it does not reproject ...
2
votes
0answers
73 views

R.Neighbors with large neighborhoods?

I'm running into problems running the r.neighbors GRASS command in QGIS. Although it will run for small neighborhoods as soon as I increase my neighborhood above a certain number it becomes unbearably ...
3
votes
1answer
2k views

Conditional Statements in QGIS raster calculator?

What is the equivalent statement of the following expression in the QGIS raster calculator? Con(((Abs("DEM" - "FSMin") > 120) | (Abs("DEM" - "FSMax") > 120)), 1, 0) I have no problem ...
2
votes
2answers
291 views

QGIS Contour plugin: Creating complex isolines leads to isolated areas

I use the contour plugin (v1.1) within QGIS 2.4 to create contour lines. I have streets with different travel costs. I observe problems for streets with low travel costs if they are surrounded by ...