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

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7
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3answers
5k views

How to access QGIS Plugin Repositories from behind a proxy?

I have been trying to teach myself QGIS by using this forum and others to help. Most of my questions can be answered by downloading plugins that are available through 3rd party repositories but for ...
3
votes
1answer
172 views

How to unload() a plugin in QGIS 1.7?

I am writing a python plugin for QGIS 1.7 (started it on QGIS 1.6 but switched to 1.7 recently). Since I switched to 1.7 my unload function doesn't seem to be working anymore. Whenever I implemented ...
4
votes
2answers
4k views

Which hardware configuration is necessary for QGIS?

What kind of hardware is necessary to run QGIS on Win XP? Closely related: Specifications for GIS desktop hardware
4
votes
1answer
315 views

Multishading: bring them together to one Raster-Image

I made a multi-hillshade with 4 different light-directions and colors and stacked one above the other, each with its own transparency. Now I want to "save" the result in one raster-image. Whats the ...
2
votes
2answers
287 views

QSpatialite install error in QGIS

I'm installing QGIS 1.7.4 in windows 7 & having problems with QSpatialite. I get 3 messages... Message #1 This DB a valid SQlite DB, but not a valid SpatiaLite DB. QSpatiaLite will now try to ...
2
votes
1answer
393 views

QGIS Time Manager Data entry

I have downloaded the Time Manager plugin for QGIS. I have created a simple test file with only 4 points, with a date attribute showing YYYY-MM-DD, each point moving forward one day. Yet it tells me ...
2
votes
0answers
122 views

Changing CRS crashes QGIS every time

When I open QGIS, and use the tools, setting -> project properties, QGIS will crash. When I also use the setting -> option -> CRS , Select new CRS also causes a crash. It looks like couldn't use the ...
18
votes
3answers
29k views

How to merge multiple layers to one layer using QGIS?

I've imported several shapefiles which where exported from an Mapinfo .tab. Several tab files are imported resulting in 20+ layers. Afterwards I want to export it to geoJSON; but I'm reluctant for ...
8
votes
2answers
741 views

Can QGIS Read Spatialite Views?

I have a spatialite database I created that spans several years of crime data. To facilitate a real-world scenario where I may simplify the interaction for a user by introducing a View that simply ...
5
votes
1answer
1k views

Can I change properties of several layers simultaneously?

I'm working on bulk data. I have a few hundred GeoTIFF images imported into a QGIS project, and I'd like to modify their layer properties - things like the no-data-value, transparency of certain pixel ...
3
votes
1answer
712 views

How to randomize colors by class in QGIS new symbology?

As a new user of QGIS, one of the tasks I frequently perform is creating a layer where polygons are colored by class, classified by some nominal field in the attribute table. I have developed a habit ...
8
votes
4answers
3k views

Open source software to merge large shape files

Some background: I have 2 polygon shape files with approximately 500,000 records each. The two files are identical in terms of field structure. Using ArcGIS 10.0 I can'nt merge these two files using ...
2
votes
0answers
799 views

OSGB36 to WGS84 reprojection 'error'

First off, I am a recent convert to QGIS and am greatly impressed with its ease of use and speed compared with the ESRI products with which I am more familiar - my congratulations and thanks to its ...
2
votes
2answers
1k views

QGIS is not able to find GRASS. Choose the path of installation folder of GRASS

I've downloaded and then correctly installed QGIS 1.7.4 for windows (Win 7 64bit is my version) in C:\Programs\Quantum GIS. But everytime I start QGIS this popup appear: "QGIS is not able to find the ...
1
vote
1answer
562 views

Reprojecting a shape to UTM33

I still have trouble reprojecting shape files :( I would like to reproject it to UTM33N / WGS84 (EPSG 32633) I think the projection of the shape might be Pulkovo 1984/ Gauss-Krüger Zone 4 (EPSG ...
3
votes
1answer
651 views

Cell calculations; QGIS,GRASS,GDAL,SAGA

I recently asked a question about trying to calculate the slope over distance (manually) using QGIS, but then I came up with another way of solving the problem, but I would have to get some help for ...
2
votes
1answer
813 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
votes
1answer
506 views

QGIS Georeferencer - Image file imports too small

I am trying to georeference a largish aerial image (50MB) to some GIS data I have and import it as a background. However the image imports extremely small - so small I cant see it! I am using QGIS ...
4
votes
1answer
515 views

Using group by to set a PostGIS datasource using QGIS Python API

I am writing a QGIS Plugin and wish to obtain data from a PostGIS table using the Group By clause using something like the following code: uri = QgsDataSourceURI() uri.setConnection('localhost', ...
0
votes
1answer
955 views

Trying to Install on MAC OS Lion and getting Python error message

Brand new to this and struggling to install QGIS on MAC OS X with Lion, I am not a techy - but noticed in the install read me that /usr/bin needs to be added to the GDAL.frameworks path. Failing to ...
6
votes
2answers
1k views

Raster generalization - buffers in rasters, expand pixels?

Is it possible to create buffers for pixels of raster files? Actually I need to expand the pixels classified as 1 (in white in the figure) with a spatial range of 1 or 2 pixels, in order to perform ...
4
votes
2answers
1k views

How to create an animated map?

I am seeking to create an animated map illustrating the simultaneous movement of different objects across a large area over time. The display should be capable of playing automatically, or by ...
7
votes
2answers
3k views

How to use Heatmap plugin and its output?

I have a layer of points which I would like to depicted as a heatmap concentration of points for visualization. In QGIS 1.8 I tried the built-in heat map plugin, leaving the default values as is, and ...
0
votes
1answer
1k views

How to generate smooth contours from cropped raster?

I’m trying to create contours from a raster layer in QGIS. On my first attempt, I cropped my raster layer in Photoshop and reimported it, but it lost coordinate data I think. I made the contours ...
6
votes
1answer
6k views

How to crop raster layer?

Can anyone tell me how to crop a raster layer in QGIS? I want to make contours from a section of a layer, and including the whole layer will create far more data than I need and slow down the ...
1
vote
2answers
166 views

How to select only areas bigger than x acres?

I would like to create a new shapefile from another area shapefile. The new shapefile should only contain all areas that are bigger than 5 acres (10.000 m²). How do I do this?
2
votes
1answer
117 views

Generating plan sets using different layer configurations

I am working on a flood modelling project that will generate a very large number of plan sets. Each set will have several plans - say a general arrangement plan and say 5-10+ sheets tracking along a ...
1
vote
1answer
218 views

Spatial Query plugin broken in MacOS version?

I'm running QGIS 1.7.4-4 on a MacOS 1.6.8. I'm trying to use the "Spatial Query" plugin but it's not loading. The plugin is activated and I can see it in the main menu Plugins > Spatial Query > ...
3
votes
0answers
3k views

How to load and view .gri and .grd files in QGIS [closed]

An online GIS Repository called DIVA-GIS (http://www.diva-gis.org/gdata) offers data in three formats - ERSI files, "DIVA gridfiles", and DBF files The DIVA gridfiles have extensions .gri and .grd ...
0
votes
1answer
260 views

How to remove polygon under other one?

Hi, lets say that green polygon is under red and part of blue with yellow stripes is also under red polygon. how can i make one polygon from every polygons that intersects my main ( red ) polygon ...
1
vote
1answer
4k views

Why can't I right click -> toggle editing Quantum GIS [closed]

I would like to delete multiple polygons at once: How to delete multiple selected polygons at once? Why can't I right click -> toggle editing Quantum GIS [ it is grayed out] ? My layer is polygon ...
2
votes
5answers
4k views

How to export labels to DXF file?

Is it possible to export labels based on Shapefile attributes into a DXF file? I use Quantum gis in Version 1.7.4. I've been reading a CSV file and view it as a Shape Layer. With the help of ...
6
votes
3answers
355 views

Real-world QGIS users [closed]

I am just beginning as a QGIS user, and I have used ArcGIS mostly in the past. I am in the position of having to defend QGIS as a viable solution for many, if not most, GIS needs for Country and City ...
2
votes
2answers
899 views

How to calculate a new raster based on nodata values from original raster, in QGIS?

I'm using the raster calculator from core in QGIS and I need to generate a new tif raster file (mask) from the nodata values of another tif raster file. I tried isnull(), but no luck. Any one can ...
3
votes
2answers
339 views

How to achieve Activity Sizing in QGIS

I have plotted 30,000+ points in QGIS by postcode, various data items for each. How do I resize these plots based on the activity at each of these points i.e. small dot for <100, larger dot for ...
6
votes
4answers
869 views

How to automatically plot intermediate contours with QGIS, GRASS GIS or SAGA GIS?

I'm mapping a steep mountain range. My main contour interval is 50 m and my intermediate contour interval is 10 m. In steep areas, the interval of 10 m is too small, so I need to leave ...
2
votes
1answer
286 views

How to port QGIS C++ plugins to other QGIS installations?

I developed a C++ plugin for QGIS using VC++ express 2008 and a QGIS dev release (1.9.90 alpha), my plugin works fine on this release and now I want to port it to other QGIS installations, so I copied ...
2
votes
1answer
287 views

Conversion of ASTER GDEM data for CFD Analysis

I need to do a computational fluid dynamics (CFD) analysis of wind over a large area of land. I have obtained the necessary tiles from the ASTER GDEM data set (in .tif format) and was wondering how I ...
1
vote
1answer
170 views

Open --> Setting --> Project Properties will shut down Qgis

When I want change my project and I select setting and the project properties . It's will give me some message, like "Exception - Bad allocation" How do fix the problem ? http://imgur.com/XEHcs
2
votes
1answer
456 views

How to solve postgreSQL error when using QGIS Cloud plugin?

I created a qgis cloud account and installed the plugin. When I attempted to Upload Data using the plugin, I got the following error: postgreSQL exception: ERROR: "MD5" authentication with pgpool ...
-3
votes
1answer
894 views

How to connect QGIS with Visual Basic?

I'm an final student at one university, i need to make one project to make web based GIS application using open source. I select Quantum to make this project. Here i want to ask anyone, how to connect ...
3
votes
1answer
323 views

Is there a way to export labels in QGIS?

I've used the v2 labeling engine to place some nice looking road labels. Now I'd like to export those labels as a point shapefile for use in another program. Is there any way to accomplish this?
3
votes
1answer
2k views

How to open or import .sdc files in QGIS?

I have some .SDC files i want to look at but i dont have arcview installed. is it possible? i couldnt even find a software that does sdc to shp conversion. any idea? i am using qgis 1.7.4 on both ...
0
votes
2answers
161 views

Need to hyper link my personal data to a shape file [closed]

I want to hyper link my personal data like excel file to a shape file. Can I do it in QGIS. Kindly help.
1
vote
0answers
372 views

error while trying to compile quantum gis: unresolved external symbol class QgsSearchTreeNode

i'm trying to compile the quantum gis sources code following the step by step how to compile guide, but i'm facing an error when code is linked. I'm compiling in Windows 7 x64 in Microsoft Visual ...
7
votes
4answers
2k views

How to close watermarks window in QGIS Openlayers plugin?

I'm using Quantum GIS Ver. 1.7.4. I have upgraded openlayers plugin 0.7 to 0.9. However when I open google satellite, a watermarks/copyright dialog box "Data Peta@2012 ..." appear in the middle of the ...
0
votes
0answers
22 views

MapCanvas : Mouse-wheel event filtering/overriding [duplicate]

Possible Duplicate: MouseWheel event filtering on Qgis I’m developing a C++ plugin for Qgis and I want to filter/override the mouse-wheel event. I created a “maptool” to select a polygon ...
2
votes
1answer
464 views

How to convert decimal point to comma in QGIS?

I am working with data in Colombia where decimal points are written as commas. I would love to create a new column in QGIS that would convert all decimal points (periods) to commas for the purpose of ...
3
votes
1answer
332 views

How to move Layer to back?

from my Plugin I've loaded a rasterlayer using the following code: fileName = "/path/to/raster/file.tif" fileInfo = QFileInfo(fileName) baseName = fileInfo.baseName() rlayer = ...
3
votes
1answer
120 views

Is there any extension to “optimize” the creation of maps in QGIS?

is there any extension to "optimize" the creation of maps in QGIS? i searched the repository, but found nothing useful, maybe i searched in a wrong way.. there are some things i am really missing: ...