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

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2
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1answer
1k views

Getting polygon shapefile node coordinates and point order

I am trying to get the coordinates of each node of a polygon in QGIS. What I basically did is use the following tools: Vector -> Geometry tools -> Extract nodes Vector -> Geometry tools -> Export ...
2
votes
2answers
152 views

Generating new shp files according to attribute in QGIS

I know that it is possible to color a vector map by attribute. I separated a map into 4 colors based on an attribute and now I want to generate a new map for each color. Is there a way to do this in ...
2
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2answers
2k views

How can I link java with QGIS?

I want to create a Desktop project on Java which shows radiation dispersion. How can i Link java with QGIS? Is there any tutorial site i can get reference from?
2
votes
2answers
3k views

OpenLayers plugin and QGIS 1.9: Error after install

After I install the OpenLayer Plugin (1.0.0) on my QGIS 1.9 this error appears: Konnte Erweiterung openlayers_plugin nicht laden wegen eines Fehler beim Aufruf seiner initGui()-Methode Traceback ...
2
votes
2answers
986 views

Using Georeference information stored in tfwx (from ArcGIS) in QGIS?

I have georeferenced some images (ArcGIS -> Update Georeferencing) which creates a *.tfwx file with the new parameters for georeferencing. I renamed it to *.tfw but QGIS is not able to read the ...
2
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1answer
740 views

QGIS ->ArcGIS Server configuration possible?

Is it possible to connect a QGIS Desktop 1.8.0 to an ArcGIS Server 10.0 ? and of course publish services on it?. The configuration would be like this Quantum GIS-> ArcGIS Server 10.0 on Amazon EC2+ ...
2
votes
1answer
467 views

How to control what kind of tags / flags are imported with osm2po?

With the help of osm2po, I have successfully inserted the contents of the italian files (italy.osm.pbf) in a pgrouting-enabled database (postgresql 8.4) It displays fine in Qgis, using rule based ...
2
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1answer
350 views

update tables data dynamically

Can u help me in creating a trigger and function so that every time i change the flag in table A the buffer distance should get changed and also its geometry field also , ie the polygon area? I have ...
2
votes
1answer
546 views

how to modify shape extents in qgis

I want to change the shape extent of some shape files, I would like to know how to do it in Qgis, since I rasterized some shapes and when I used the calculator to add them, the resulting raster had ...
2
votes
2answers
3k views

Is it possible to extract Coordinates of Polygon Centroid in QGIS?

I have created polygon centroids using one of the "Geometry Tools" but I would like to extract the actual coordinates into Excel for further work. Is this possible?
2
votes
1answer
865 views

Couldn't load SIP Module

After reinstalling QGIS, the desktop program runs but generates the python error "Couldn't load SIP Module Pythin support will be disabled" Because of this error, no plug-ins will load. I found a ...
2
votes
2answers
2k views

How to install OpenLayers plugin in QGIS1.8

I am using QGIS 1.8.0 on Windows 7 (32-bit) but am unable to install the OpenLayers plugin. The Python plugins menu does not include OpenLayers on the plugin list. Can it be somehow added manually? ...
2
votes
1answer
1k views

Importing QGIS core into Python on OSX

I am interested in learning how to write standalone scripts using QGIS. An answer to my previous question directed me to the PyGIS CookBook which has the following instructions for importing the ...
2
votes
1answer
682 views

Plot the nodes of the shortest path found by dijkstra algorithm

I am using qgis and pgrouting plugin to find the shortest path between two nodes and display the route. Currently, the plot shows the shortest path. However, I also want to know which nodes the path ...
2
votes
1answer
291 views

How can i include program form (created in Designer ) to my QGIS plugin?

How can I include a form created in Designer in my QGIS plugin? And how to get controls values (textbox,label,etc)?
2
votes
1answer
1k views

Problems with Google layers plugins

I currently use Quantum GIS 1.7.4 at work and I have trouble to open Google layers extension. In fact, when I start QGIS 1.7.4 the following message appears and I cannot use Google layers extension. ...
2
votes
2answers
320 views

how to extract overlap from non-dissolved buffer zones in qgis 1.7.4

I have a shapefile with the inventory of all limetree in a region. I made a buffer around each tree. So, the place where buffers overlap each other is the best place to put beehives. Is there a way ...
2
votes
1answer
989 views

Why does my PostGIS query fail with “current transaction is aborted”

I'm trying to create a vector layer in a QGIS project using a PostGIS query. QGIS is returning the following error: Query failed 1 cursor states lost. SQL: CLOSE qgisf1 Result: 7 (ERROR: ...
2
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1answer
399 views

How to fix “Couldn't load plugin …” and “ImportError: No module named …” in QGIS plugins?

After installation of Quantum GIS I tried to use Table Manager Module, but I can't do it. Here is the message: Nem tudom betölteni a 'tablemanager' modult innen: ['C:/PROGRA~1/Quantum GIS ...
2
votes
3answers
2k views

Qgis Python code library documenation.

I'm looking for python documentation for specific operations in the Qgis python console. I know there is no suggestions simular to Arcpy but I would like a pure list of operation code lines as ...
2
votes
1answer
10k views

Python :ImportError: DLL load failed: The specified module could not be found

I am working on Python plugins for QGIS. I set my variables as PATH :=C:\OSGeo4W\apps\qgis;%PATH% PYTHONPATH:=C:\OSGeo4W\apps\qgis\python But when I try to run my .py file in IDLE I get an error ...
1
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2answers
85 views

Why do my points end up in Africa? (should be Croatia)

I have the correct coordinates in a excel file, but when I import the file, the point always goes to the wrong place. (I need it in Croatia, and it puts the point in Africa) I've tried chaging CRS ...
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0answers
95 views

Viewshed analysis plugin on QGIS keeps resulting in errors

I've been trying to test the Viewshed analysis plugin on QGIS 2.10, but it keeps giving back error messages. I've tried to reduce the radius area and have also reprojected both my DEM and my point ...
1
vote
1answer
110 views

pixel values beyond valid range in QGIS

I opened a sub-dataset of an HDF file (NDVI layer of MODIS HDF file) in QGIS, but pixel values are beyond the valid range (-2000,10000). I see many pixels way less than -2000 and way over than 10000. ...
1
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1answer
75 views

Failed to create memory layers in QGIS application on Linux

I have written a python class which reads properties of map layers from an XML file and creates appropriate memory layers. I have developed and tested this code with QGIS 2.8.2 on a Windows 7 machine ...
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1answer
292 views

nearest neighbor query in SpatiaLite

I am trying to find the nearest line to each point in a layer, and I have over 1 million points. I want to be able to associated the closest unique line ID with the point unique IDs. I have tried to ...
1
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2answers
1k views

QGIS Server 2.8 on Windows Server 2012

I'm attempting to install QGIS Server 2.8 on Windows Server 2012 R2. I've followed the instructions here and here. I've moved all the dlls from OSGeo4W to SysWOW64 for completeness' sake. I'm still ...
1
vote
1answer
150 views

How to call default tool in QGIS inside plugin using python script?

I want to create a plugin which can draw irregular polygons in QGIS. For that, I want to call the Select features by freehand default tool inside my plugin. How can I do this within a python script?
1
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1answer
128 views

Multiply whole column with the field calculator in QGIS

I have a layer with the field size. I did some mistake with the value and now I need the values multiplied by 16. But instead of going through 500 lines and recalculating them I would like QGIS to do ...
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2answers
391 views

Imported TIF has dark gray background instead of white

using QGIS 2.6 I import a TIF file, and expect the import to show an image that has black lines on a white background (with some other colors here and there), as the native windows viewer will see a ...
1
vote
3answers
138 views

Appending data in PostGIS database with QGIS?

I 'm running postgis with qgis 2.6. I created a database and tables that i need to update with new datas provided with shapes. I cannot find how to insert them in table. All attributes both shapes and ...
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0answers
60 views

How to determine Affine Transformation Parameters? [duplicate]

I try to use the qgsAffine plugin to do the transformation. But no idea in its usage. Anyone can post an example. Many thanks!! How to find the transformation parameters? I found some posts suggest ...
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1answer
820 views

QGIS SLD in GeoServer

I rendert a beautiful with QGIS based on OSM data. Now I want to publish it via GeoServer. I am new to GeoServer but as far as I it does not accept SLD files created by QGIS. My GeoServer cannot ...
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3answers
213 views

How to complete the roads output of PostGIS?

I converted the file I exported from OSM to PostGIS using osm2pgsql. I have opened the table's outputs to QGIS and I saw data are not complete compare to OSM editor view. Most of the roads are broken ...
1
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1answer
99 views

QGIS - View bathymetry info in the status bar

PolyGo suggested that I split my earlier twofold question into separate questions. So: I am new to QGIS or any GIS software so please forgive me if the answer is obvious to you. I wish to view the ...
1
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1answer
201 views

Plugin of Multiple buffers in QGIS

I hope to create a plugin to do multiple buffers in QGIS. This is my script: """/*************************************************************************** izisse_test ...
1
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3answers
268 views

What is the math behind rasterization?

I'm taking the first steps in QGIS (version 2.2 Valmiera) and I am having some difficulties in knowing what mathematical criterion that QGIS uses when converting polygons (shapefile) to raster. I'm ...
1
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1answer
145 views

How to close spaces within a polygon in QGIS 2.2?

I have a shapefile displaying the borders of several city units. One of its polygons, however, had free space consisting of four vertices in it. I created another polygon inside the free space and ...
1
vote
1answer
544 views

Intersect between polygonal shapefiles error

I'm encountering a problem when I try to intersect two different shapefiles. They are all new shapefiles I created to descibe the land cover and the land use of a city. The problem occurs when I ...
1
vote
2answers
6k views

Drawing tools to add circles, arrows, lines for QGIS?

I'm pretty new in QGIS and i'm searching a drawing tool like it is possible to find in microsoft word or excel. I search something very user friendly (for dummies!) to add circles, arrows, lines... ...
1
vote
1answer
1k views

How to indicate flow of a watershed feature?

While tracing and digitizing rivers, streams, rivulets, etc., is it possible to indicate the direction/flow in the shapefile on QGIS? I'd like to avoid using map labels. Ideally, when done tracing, I ...
1
vote
1answer
393 views

Is it possible to link a QGis project with an excel file?

I have an Excel file with coordinates and I have used this file to plot the coordinates in QGis. I was wondering if it was possible to permanently link the excel file to the QGis project, so that when ...
1
vote
1answer
200 views

Are unicode symbols supported in QGIS labels?

I want to use unicode symbols in a QGIS label - is this supported? I.e. I have this expression for labelling a line: case when xat(-1) - xat(0) > 0 then 'GF ->' else '<- GF' end and ...
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vote
1answer
650 views

How to make GRASS and SAGA tools capable to use in QGIS?

I installed QGIS, GRASS and GDAL by OSGeo4w package, and as I finish the installation, I want to use GRASS tool, I face this problem: But I already installed GRASS and SAGA, how to make those tools ...
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vote
2answers
1k views

How to avoid “Handle bad layers” message when using QGIS Flowmapper plugin?

In QGIS, if I close a project and try to open it a few days later I often get a message that says "Handle bad layers". This is very frustrating because when I open the project various layers will have ...
1
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1answer
198 views

Save input in plugin as pdf format file

I m trying to make QGIS plugin with plugin builder that compare 2 map scale with Input1 and Input2 as input scale and show recommendation after clicked recommendation button. I wrote my code like ...
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2answers
9k views

How to export and import gps points from Garmin 62S and QGIS

I'm pretty new to using QGIS and I'm curious about how to import and export GPS points created in QGIS. I have QGIS 2.0.1 dufour on windows XP and a Garmin 62s. Any suggested walk throughs would be ...
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0answers
252 views

Ecw not supported with qgis-mapserv-fcgi but supported in QGIS Desktop - resolved

I have problem with qgis-mapserver version 2 and ECW. Qgis Desktop works well with ECW (gdal support for ecw with the library ERDAS_ECWJP2_SDK-5.0) but not qgis-mapserver (not supported file in ...
1
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1answer
188 views

QGIS Python Composer Attribute Table has no content

I post 2 Month ago the same question. So I try it a second time with more code. My Problem still is that I add at the composer a attribute table and in this table there is no content. My Code: ...
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2answers
449 views

Where I can download QGIS 1.8 for Mountain Lion?

I've encountered some problems running my old 1.8 project in 2.0. I would like to reinstall QGIS 1.8 but seems that there are no more 1.8 installer in KingChaos. In QGIS "all releases" there isn't.. ...