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

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634 views

How to export x/y coordinates from geodata?

I am a novice about Geographic Information Systems. Now I want to get real line segment dataset to do an experiment. So I searched it, and found the site that includes the real data: ...
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1answer
913 views

Rasterize vector layers with different extents into identical raster grids with QGIS

I am working on a quite simple spatial potential analysis using QGIS. I have some ArcGIS knowledge, but I am new to QGIS. My task is to identify the functional inner city of a region based on ...
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1answer
2k views

How to transform World data from EPSG 4326 to EPSG 3857

I have tryed different opensource tools to transform a world data shapefile from 4326 to 3857 but I always have an error. Im not sure, but is it because of Antartica? I have tryed with GDAL and QGIS ...
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1answer
309 views

Pseudo Mercator error?

I'm mapping on QGIS, I have a vector layer and his CRS is on EPSG:4326 - WGS 84, but also I wanted to put a satellite image, so when I do it, the image use WGS 84 / Pseudo Mercator. The problem is, ...
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2answers
2k views

How to resolve missing Python module (importlib) for GRASS/Sextante?

I have installed the nightly build of QGIS 1.9 from Larry's Dakota Cartography site, and have downloaded the latest Frameworks from William's Kyng Chaos site. However, I am unable to install the ...
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1answer
978 views

QGIS Plugin Windows

I have written a QGIS plugin (RTools) which acts mostly like a independent plugin (minimal interaction with QGIS core functions). On Linux both QGIS and RTools were build using QT 4.8 on Qt creator. ...
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1answer
1k views

How to dissolve polygons and aggregate their data in QGIS? [duplicate]

I have a shapefile (one layer) with my country but I have a problem. It is divided into 4 entries (prefectures), and I want it as one, not 4. Also, there is a table with some data, and I want to ...
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0answers
60 views

Purge Layers from QGIS [duplicate]

I have created numerous databases from a base source and merely added and removed various layers then saved as a new project. There were more layers common than not in common in each project. However ...
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2answers
491 views

area values determined with field calculator become null when saving

using field calculator in Qgis 1.8.0 to get the area, it shows just right at first but when I save it, the values become Null. help please
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1answer
316 views

QGIS cannot view raster loaded to PostGIS through raster2pgsql

I tried to load a raster GeoTIFF image to a PostGIS database using "raster2pgsql" following the OpenGeo Suite Manual. The command I used is: C:\>raster2pgsql -s 4283 -I -C -M "C:\Program ...
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2answers
2k views

QGIS: using postgis can I define a layer using sql?

I have a vector layer (call it master) that is stored in postgis and consists of a number of line segments. I also have a collection of sub layers that consist of subsets of the master layer. I can ...
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1answer
698 views

“Easy Custom Labeling” arrows: How do I get them?

I have installed the Easy Custom Labeling plugin, but haven't figured out how to make the "Generate lines" function work. When I click on the tool in the toolbar, it opens the dialogue to specify my ...
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2answers
2k views

Can QGIS (1.8.0 Mac) rotate the entire view of a project?

Can QGIS (1.8.0 Mac) rotate the entire view of a project? that is, have north pointing in a direction other than up on the screen and on output? of course, while still allowing adding new layers etc.
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2answers
140 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 ...
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3answers
3k views

How to auto fill or delete sliver polygons without losing precision?

I am developing some boundaries in which precision holds the key value. Using ArcGIS 9.3 I am converting lines to polygons using the "feature to polygon" tool. The lines are accurate but I find ...
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1answer
306 views

How to set tolerance value of Geoprocessing tool in QGIS?

Is it possible to set tolerance value of geoprocessing tool on QGIS. History is below. There are two polygon which have to be the same position. so, I set topological rule "A must covered by B" on ...
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1answer
483 views

Desktop client symbolozing a WMS layer by sending SLD to the WMS server?

Objective is simple: finding 'desktop software' (such as ArcGIS, QGIS, etc) that can load a WMS layer, and then send its own SLD to apply to the WMS server in order to get the WMS layer back with the ...
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1answer
488 views

Problem connecting to localhost PostGIS

When I try to connect to a small localhost PostGIS database using QGIS, I get the error message: FATAL: no pg_hba.conf for host "fe80::4528:3236:418a9e7b%10" user "postgres", database "nyc", SSL off ...
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0answers
55 views

Add regular points to each polygon in QGIS [duplicate]

Possible Duplicate: assign and move centroids to their polygons I'm trying to find out a method to define a unique ID based on specific coordinates for each polygon of a shp. The problem is ...
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1answer
94 views

I have a .sid image but can't figure out the CRS

There is a .map file: OziExplorer Map Data File Version 2.2 Tiritir_2.sid C:\OziExplorer\Maps\Islands\Tiritir_2.sid 1 ,Map Code, Geodetic Datum 1949,WGS 84, 0.0000, 0.0000,WGS 84 Reserved 1 ...
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2answers
1k views

How to convert a Shapefile from bessel1841 to WGS84?

I would like to convert a shape file which has +ellps=bessel to +ellps=WGS. In my understanding, even QGIS1.8.0, it is impossible. Let me know the free software which is able to convert shape file ...
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0answers
362 views

QGIS project on QGIS server — cannot load wms layer [duplicate]

I've created a qgis project on QGIS 1.8, copied it onto the QGIS Server, and am trying to load the project as a WMS Layer back into QGIS. There is one vector layer in the project. Paths have been set ...
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2answers
2k views

How to fix QGIS PyQGIS package?

I have a broken package that is preventing QGIS from loading python plugins, updating itself, or even un-installing. The main symptom of this problem is the following message that appears when QGIS ...
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2answers
551 views

How can I fix Print Composer errors due to huge file size?

I have put together a map using the British OS Strategi data set which is pretty densely detailed. It is surveyed at 1:250,000 and so contains roads down to track level, rivers, villages, railway ...
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2answers
3k views

What do I need to change to get scale bar units other than degrees?

Measurements done in QGIS on my project are done properly using whatever unit is set in: Settings > Options > Map Tools > Preferred measurements units but the scale bar decoration and scale bar in ...
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0answers
579 views

How to reproject a raster in QGIS? [closed]

I wanted to reproject raster file from UTM to decimal degree in QGIS version 1.7.1 or 1.8.0.. I could reproject one raster file before in QGIS Version 1.8.0. I have tried again, but now we cannot ...
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2answers
508 views

Cannot get changeAttributeValues() to work in a loop

I'm trying to use QGIS to loop through a set of points, find their elevation from a DEM and use that value to update the point layer's attribute table. The loop works fine until I try to use ...
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1answer
392 views

Polygonizer plugin for QGIS halts in Windows?

I've had some success and some problems using the Polygonizer plugin in the past. I'm using Polygonizer 2.1 in QGIS 1.8 on Windows 7. I'm aware there are sometimes problems using Polygonizer in ...
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0answers
429 views

QGIS: opening a shapefile without an exclusive file lock [closed]

UPDATE: I did some analysis of what happens with the locking and it looks like QGIS doesn't use an exclusive lock. It just requires (non-exclusive?) write lock to the file. So this C# code fails: ...
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2answers
470 views

How do I intersect DEM and a polyline?

I'm working on Qgis, I need the longitudinal section of a river. Thanks
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1answer
373 views

How to draw lines for diagrams?

Just before submitting bug: in Diagrams, there is possibility to use Position AroundPoint or OverPoint. Whatever I choose Line Options selection stays gray: I can't choose any line. So, I suggest ...
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1answer
626 views

Openlayers Overview and OpenLayers versions

I have installed OpenLayers and the Openlayers Overview plug-ins but I am not sure if they are working. I can create new 'open' layers from the Openlayers plug-in drop down, but when I try to add a ...
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4answers
4k views

ECW on QGIS 1.8 (Ubuntu 11.10)

I'm trying to deal with an ECW file with QuantumGis 1.8 Lisboa, on Ubuntu 11.10. Obviously it tells me that .ecw is not a supported kind of file on QuantumGis. I have tried to install all the ...
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1answer
686 views

How to fix Exception: forward transform failed with error: latitude or longitude exceeded limits

Export to vector file failed. Error: Failed to transform a point while drawing a feature of type 'Dingalan_Brgy_Boundary'. Writing stopped. (Exception: forward transform of (5731.78, 29676.2) failed ...
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0answers
2k views

Error when importing shapefile to Postgis database

I was trying to import shp to postgis database and i get the following error: Importing with configuration: adresy92, public, geom, C:\Users\tomek\Desktop\adresy92, mode=c, dump=1, simple=0, ...
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2answers
621 views

Need help getting started with QgsComposition

I am using QgsComposition for the first time, but I fail at the first step :-( mapRenderer = iface.mapCanvas().mapRenderer() line 31, in mapRenderer = iface.mapCanvas().mapRenderer() ...
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1answer
250 views

QGIS Projections

I am new to the GIS world and have faired pretty well with ArcGIS 9.3, learned and still learning on the job. I would like to get a better handle on QGIS though. I linked the files from my dropbox. I ...
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0answers
352 views

QGIS & WMS: Different aspect ratio between width/height and bbox

I am experiencing a small screen space offset when using a WMS layer (origin is GeoServer 2.1.4). Looking at the requests from QGIS (1.7.4) to my GeoServer I realised that the aspect ratio between the ...
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1answer
347 views

Map missing in map composer and when I print map

I am new to QGIS and am probably missing something but when I set up a new composer and add a map to the page nothing appears. I have pressed the render button and the up date with no results. When I ...
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1answer
2k views

How can I create a custom form to display the attributes of the selected object?

I have already appealed to the selected objects, and found a way how to put them in a MsgBox. But I need to output was in the form
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0answers
691 views

Symbol rotation by using rotation-field [closed]

I want to rotate my symbols using the rotation-field in my atribute-table. After choosing the rotationfield, my symbols become invisible (the text is still there). What happend? Thank you! Martin
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1answer
2k views

Projection in QGIS - Scale bar and measurement

When I load a *.csv file (delimited text) as a layer in QGIS, the scale bar shows degrees (for example 0 to 10 degrees). When I uncheck On the fly projection and change the units for feet or meters, ...
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3answers
2k views

What is the problem with the merge shapefiles tool in QGIS?

I'm having trouble merging shapefiles in QGIS. I'm using plugin ftools 0.6.1 and I get this: Any workarounds someone may know of? Thanks
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2answers
1k views

How to project TIGER & WGS84 to Spherical Mercator?

So I've been banging my head on this for about a week now. I'm using QGIS on a Mac. I have various shapefiles in WGS84 and Census TIGER NAD83 (EPSG:4269) and I would like to give them the same ...
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1answer
12k views

How to fix Qtcore4.dll can't find procedure entry point? [duplicate]

Possible Duplicate: How to fix QGIS error “Entry Point could not be located”? I am working with QGIS, python2.5 and pyqt4 for py2.5. My system variables are as follows: ...
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1answer
518 views

How to use buffers to estimate the attribute data for a given polygon?

I have two layers: point and a polygon. The point layer has lat/long and I have created buffers of a 1/4 mile. The polygon layer has data such as age and income. Is there a plug-in that can ...
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1answer
842 views

How to change the the style of a vector layer programmatically?

I want to change the style of the polygon contained in the vector layer. Is there any API available? (I can click the properties of the shapefile, then select the style and change the symbol ...
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2answers
2k views

How to set cell size for vector to raster conversion in QGIS GRASS plugin?

I'm converting a vector (loaded in GRASS plugin in QGIS (1.7.0.-wroclaw) and would like to convert this to a raster with a defined cell size. At the same time I need a value from the attribute tabel ...
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2answers
4k views

Hyperlink relative paths to files in points layer in QGIS?

I would like to add hyperlinks to each point in a points layer in QGIS 1.7.0 running on Mac OS X 10.6.7, but I have several requirements: (1) Each hyperlink has to be a relative path to the linked ...
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0answers
45 views

How to relate a Spatial and Non Spatial table in PostGIS to be visualized in QGIS

first of all I'm quiet new in PostGIS. I'm working in pgadminIII with postGIS. I have in one database two tables. See the two tables SQL Pane. CREATE TABLE gw_body_characterisation2 ( ...