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

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3
votes
3answers
841 views

Finding centrelines from polygons?

I was wondering if there is a way to create centre lines from polygons in QGIS? I have a polygon layer, but ideally need the centrelines as a separate file. Thanks, Alan
0
votes
2answers
488 views

How to find the proper coordinate reference system with two sets of data using different measurements or too convert one system into another

I have two different entries of data in two different spread sheets. One of the spread sheets uses a coordinate reference system that I have no idea what the units of measurement are. the properties ...
0
votes
0answers
186 views

QGIS Georeferencer and Coordinate Systems

I'm having an issue with Ubuntu and Windows versions of QGIS where the georeferencer does not properly assign the coordinate system to the output raster. When I assign the output CRS to 'EPSG:900913 ...
11
votes
9answers
11k views

How to convert KML to shapefile without losing attributes?

I'm new to QGIS and all geoinformation itself but have to work on some difficult stuff. I have a KML file with hundreds of points. To each point there is information, such as Name, Power, Age (it's a ...
6
votes
2answers
1k views

Is there a way to create a Personal Geodatabase in QGIS?

I believe I know the answer, but I wanted to ask. Is there a way to create a Personal Geodatabase in QGIS? I know QGIS can view Personal Geodatabases, but can one be created? I have a project where ...
1
vote
2answers
136 views

How can I save a column from the attribute table of a vector layer to a variable?

I am trying to write a python plugin for QGIS that can convert three vector layers into an object File for an urban climate model. Unfortunately I am stuck again with a possibly easy question: How ...
5
votes
2answers
148 views

Why the modifications I do in QGIS doesn't appear when I save an OSM file I created?

Through QGIS I loaded an OSM file I created and I'm trying to visualize what happens with the file in terms of codes after some modifications like adding points, lines or polygons. But the problem is ...
6
votes
2answers
340 views

How to simply label raster cells?

I think the title says everything but: I want to generate a small sample raster (eg. euclidean distance or cost distance) to explain the method of cost-distance analysis, and I'd like to label the ...
6
votes
2answers
2k views

How to change null values raster values to 0 in QGIS?

I need help... I'm having problems with QGIS. I have some rasters that appear to have null values, even though I reclassified them to obtain a boolean raster :( How can I change the NULL values to 0?
2
votes
1answer
61 views

Problem compiling QGIS against trunk - georeferencer

I got problems compiling QGIS (trunk) this morning. The georeferencer seems to be the source of the problem: [ 81%] Building CXX object ...
1
vote
1answer
342 views

How to get back closed panes in QGIS 1.8?

I was using the map composer in QGIS 1.8 in Mac OS X 10.6.8 today and closed a couple of the object attribute panes on the right side of the map composer. However, I can't find a way to get those ...
2
votes
0answers
277 views

How to access mysql data from python built-in console?

I'm writing a QGIS Plugin, and somewhere I want to present data from a MySQL database. It's simple data(strings,etc), not Geospatial, or vector data. I'm familiar with querying databases from python ...
13
votes
2answers
476 views

What should a QGIS course for advanced ArcGIS users cover?

I will build a 16 hour (2 day) course on QGIS for ArcGIS users. The target users that breathe and sleep ArcGIS. As we're trying to reduce our costs, we're thinking of switching some people to QGIS and ...
0
votes
1answer
279 views

Problem in Spatialite database creation

When I try create a new DataBase, Spatialite plugin return the dialog error box: The SQL query seems to be invalid. no suck table: views_goemetry_columns When I click in OK button, a second dialog ...
0
votes
1answer
1k views

How to convert a regular point grid to raster? [duplicate]

Possible Duplicate: How to convert a point grid to a raster? I´d like to convert a regular grid (25 meter) of points (XYZ) to a raster. I have tried the GRASS-tool r.in.xyz but I always get ...
4
votes
1answer
338 views

How to create a custom data viewer on top of QGIS?

I was exploring the possibility of creating a simple Data Viewer based on QGIS. I would like to create an simple application that will open QGIS up with a limited set of tools & menus. QGIS would ...
4
votes
3answers
1k views

Why won't the QGIS Lisboa MSYS and OSGeo4W shortcuts launch?

I'm trying to deploy Quantum GIS Lisboa to 64bit windows 7 machines the installation works fine but the shortcuts wont run With an error Windows cannot find "C:\Program" This also happens on XP sp3 ...
3
votes
1answer
219 views

Help with null values in rasters

I need to add different boolean rasters of the distribution of some species, since we need to obtain a single file that shows the locations where there are more than one species occurring. To do ...
2
votes
2answers
121 views

Invalid Username When Developing a QGIS Plugin on Mac

On a fresh Mac OSX 10.8 install, I've installed Quantum GIS from Kingchaos binaries and it's running fine. I'm trying to develop a plugin for QGIS using Plugin Builder. The skel that Plugin Builder ...
1
vote
1answer
255 views

How to join different line segments between points into one entity in QGIS

I have a .shp file of pipe lines. I want to join all the pipes between two valves to be considered as one segment in QGIS. Help would be appreciated. Thanks
3
votes
1answer
736 views

How can I get my Qgis area calculations in metres rather than degrees? My shapefiles are projected using WGS 1984 UTM fuseau 35 Sud

I am using Qgis 1.7.4 to calculate the area of polygons. My shapefiles have been projected using the coordinate system WGS 1984 UTM fuseau 35 Sud, but my area calculations are still displayed in ...
3
votes
1answer
365 views

Georeference problem including EPSG 102067 projection

I'm Qgis user from Czech Republic. We have a spatial national coordination system (Krovak system) having positive X axes pointing to the south and positive Y axes to the west. Many geographical ...
4
votes
1answer
416 views

Is there a purge function to remove layers from a qgs file which are not present in the Layers pane?

I have some QGIS projects that I've been using for long time, adding and removing layers, updating reference to deleted or moved files etc. Opening with a text editor the qgs file I see that it ...
3
votes
2answers
96 views

vector layer, no more editing is allowed

I have a polygon vector layer with already 529 objects but without any attributes so far and now I get the message that shapefiles without attributes are treated as write protected. What can I do to ...
2
votes
1answer
444 views

How to join two polygon layers into a resulting layer with overlapping polygons merged together (including attributes)

I am trying to find a method (in QGIS and/or GRASS) to join two layers of polygons into a resulting layer with merged overlapping polygons. It's hard to explain in words, so I've drawn a simplified ...
2
votes
1answer
288 views

How to find the nearest single point?

I have two shapefiles containing each one set of points, set A and set B. One set is my random selection (set A), the other is a list of communities (set B). For each point of the random selection ...
3
votes
2answers
264 views

Why can't I see all records in my personal GDB in QGIS?

I am running QGIS 1.8. I have a layer from an ESRI Personal GDB. There are 431 features in the layer. When you load the layer into QGIS, and look at the Metadata properties, it shows the number of ...
2
votes
1answer
817 views

How to create a line in a given distance to an existing one?

I am looking for a possibility to create a second line in a given distance to an existing line. The existing line is curved, so simply create parallel line segments with CAD tools will not work. Any ...
1
vote
1answer
137 views

QGIS 1.8 Desktop and Ubuntu 11.10

I'm working with QuantumGis 1.8 Desktop on Ubuntu 11.10. Two days ago the program crashed while I was working with some WMS layers and then it hasn't been working anymore. When I open QuantumGIS ...
2
votes
1answer
181 views

How can I apply correct colours to an elevation raster?

I have a problem to display elevation data with pseudocolours. The channel 1 is from -3.40282e+38 to 149.717 . A colleague used 1.7. and it looks like it should (from blue to Red) when I use QGis 1.8 ...
1
vote
1answer
178 views

Why are Postgis sequences not automatically updating in QGIS?

I'm adding new features to a polygon datasets in QGIS. The data is held in PostGIS but when i have a look at the attribute table for the polygon the gid field is not automatically updating, the entry ...
3
votes
1answer
957 views

QGIS: How to load feature (.qml) styles from python? [duplicate]

Possible Duplicate: How to style a layer from console? I'm trying to set the styles for a vector layer by loading the .qml file in the python console. The qml-style file contains all ...
13
votes
6answers
774 views

Which topics are essential for a crash course in QGIS?

What topics do you think are essential in a 25-hour "crash course" introduction for Quantum GIS? What topics do you think are nice extras to be included in such a course? Target audience: Zero or ...
0
votes
0answers
423 views

How to do a spatial join if QGIS 1.8 keeps crashing?

I am trying to perform a simple spatial join (adding polygon data to points) in QGIS 1.8: target vector: points join vector: polygons take attributes of first located feature keep all records ...
2
votes
4answers
906 views

QGIS locked into fullscreen mode on Ubuntu 12.04

No crash in this case, but I made the mistake of toggling to fullscreen mode on my netbook running Ubuntu 12.04. It's now impossible to escape this "No Menus" view, and it seems to have disabled the ...
6
votes
1answer
672 views

C++ Code Examples in Quantum GIS 1.8

I am trying to utilize the C++ code examples from blog.qgis.org, specifically Tutorial 4, Adding Rasters to QGIS Map Canvas. I am successfully able to run the example loading a GeoTIFF with QGIS ...
3
votes
1answer
282 views

How to make a minimal distance matrix for polygons using QGIS?

I have a set of polygons and I want to find minimal distances between the edge of each pair of them. It's similar task as in this question: How to find the minimum edge to edge distance of polygons? ...
1
vote
2answers
509 views

QGIS FIle Read Error when opening an existing project

My computer will not open a project i have been working on for weeks! it is coming up with an error of Project file read error: unexpected end of file at line 1 column 1 for file ...
1
vote
0answers
25 views

Why can I not start Quantum GIS? [duplicate]

Possible Duplicate: How to fix QGIS error “Entry Point could not be located”? Why can I not start Quantum GIS? What do I do about this following error message? "The procedure ...
2
votes
1answer
537 views

merge raster images: error message procedure not found

I am using QGIS 1.8.0. Whenever I try to merge raster images I get the following error message: Traceback (most recent call last): File "C:\PROGRA~1\Quantum GIS Lisboa\bin\gdal_merge.py", line 36, ...
6
votes
1answer
2k views

Is there a way to export data with coordinates from QGIS to a csv file

I have saved waypoints from my Garmin as gpx and have successfully imported them into QGIS. Is there a way to now export the layers into a csv file with coordinates? I've tried the export to csv but ...
2
votes
1answer
268 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 ...
0
votes
0answers
34 views

Modifying shape extents in qgis [duplicate]

Possible Duplicate: how to modify shape extents in qgis I want to change the shape extent of some files, I would like to know how to do it in Qgis, since I rasterized some shapes and when I ...
1
vote
1answer
169 views

Break between two raster layers (topographic maps)

I have the following problem [in QGIS]. In displaying two raster layers (topographic maps), a white area appears between the two. If I apply transparency to one of the layers, this white area still ...
4
votes
1answer
168 views

Dropdown menu to select vector layer from current displayed layers in qgis

I'm trying to write a python plugin to create an input file for an urban climate model out of three shape files. One of the shape files contains the buildings (polygon), one the trees (point), and the ...
10
votes
2answers
322 views

Is there an automatic function in QGIS to package all shapefiles in a project for transferability?

In my project, I use a lot of geodata from different directories. Now I want to give the QGIS project to a colleague (eg on a CD). Is it possible to copy the shapes from different directories ...
1
vote
1answer
892 views

Why can't I install python-qgis on Ubuntu 12?

I am with ubuntu 12 and Qgis 1.8. I have installed QGIS and grass plugin but I can't install python plugin. How to install python plugin with dependeny in Ubuntu? ~$ sudo apt-get install python-qgis ...
1
vote
0answers
50 views

How to call a method when self.iface.actionSelectRectangle().trigger() is released?

In my QGIS python plugin I use "self.iface.actionSelectRectangle().trigger()" to select features. I also have a button which changes the attributes of the selected features. Is there a way instead ...
0
votes
1answer
350 views

Print Composer Problems with Export as PDF [duplicate]

Possible Duplicate: QGIS Crashes when writing to PDF My QGIS crashes during the export of maps to pdf. I already uninstalled and installed QGIS twice. The function worked for several times ...
3
votes
1answer
223 views

What is status of OpenSceneGraph (OSG) plugin for QGIS? [closed]

Does anyone know if the OSG plugin for QGIS is working? If so does anyone knows what the future plans is for OSG plugin in QGIS? I am using QGIS version 1.8.0-Lisboa. I keep getting the following ...