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

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18
votes
1answer
4k views

How to define new custom projections in QGIS?

I'm trying to define a projection in QGIS. I want to add North America Albers Equal Area Conic. From the spatialreference site I copied the proj4 line: +proj=aea +lat_1=20 +lat_2=60 +lat_0=40 ...
1
vote
1answer
681 views

1-band raster colour table workaround in QGIS

Does anyone know what the workarounds are for the 1-band raster colour table plugin in QGIS? Currently I find it will run once, then crash on the second iteration. The workaround I use is to delete ...
2
votes
1answer
607 views

How do I subdivide and edit polygons preserving topology?

I'm using QGIS. I have a layer made up of many adjacent polygons - let's call them "countries". I currently use the Atlas plugin to export each "country" polygon to a .png file. I want to further ...
3
votes
3answers
841 views

Design fiberoptic network in QGIS?

I'm a GIS newbie trying to design a fiberoptic network in QGIS. What I'd ideally need is to draw lines on top of a map or orthophoto, assign a name/id to each line and a type. Get a list of all the ...
4
votes
3answers
762 views

How to create network simulation / temporal models for videos?

I know of ArcGIS Tracking analyst and QGIS Time Manager. I have a transportation network with time based schedule for buses. I will create time aware shapefiles from this data. Is it possible to ...
1
vote
1answer
75 views

Are there Bookmarks with selection highlighted in QGIS?

I have a search query on the attribute table which highlights the features and then zooms to that particular layer. I take a bookmark for this particular view with the selection being highlighted. ...
-2
votes
1answer
1k views

I need QGIS routing plug-in [closed]

I am new to pgrouting. How does it work? What benefits can I get from it? I tried the examples, read some articles, but could not find the QGIS routing plugin for Windows. It is not showing up in the ...
2
votes
2answers
294 views

Is code completion available in QGIS Python Console?

I wanted to know if the autofill functionality is available in the python console for QGIS as the one available in ArcGIS Desktop's Python Console or am I supposed to hardcode it.
1
vote
2answers
735 views

Resources for python scripting [duplicate]

Possible Duplicate: QGIS tutorials and resources I would like to know regarding the available resources for starting to learn about python scripting for QGIS.
0
votes
0answers
259 views

Missing QGIS python plugin database connectors

I am working with python plugins for QGIS.I developed my plugin and inorder to incooperate the same into QGIS i copied the folder in C:\Documents and Settings\comp90\.qgis\python\plugins I opened ...
4
votes
2answers
4k views

How to give multiple colors to features within a single shapefile?

I want to give multiple colors to different features within a shapefile based on attribute values , is this possible in QGIS ? If yes what is the procedure ? Is there a way to provide color by means ...
13
votes
6answers
5k views

Why is the performance speed between ArcGIS and QGIS so different?

Ok I am not a programmer but a prolific GIS user. I know that QGIS is written in C++ and ArcGIS in ??? but for most of my tasks lately I always try to use QGIS not only because it is free but due to ...
4
votes
6answers
7k views

How to divide a single polyline feature into multiple features based on points located on it?

I have a shape file that contains the bus route information for a city. I want to do two things.. Merge all the existing rows so that just one feature represents all the routes... I have a Points ...
2
votes
2answers
160 views

After two buffers operations (+/-), why is the result file bigger than the original?

First file ( .shp ) had 1000KB, after 2buffers ( buffers on polygon, 1st buffer +100, 2nd buffer -100 ( small things near polygon should be removed )) in quantum gis file grown to 1500KB, and after ...
21
votes
5answers
4k views

Is there any model builder in QGIS or other open source GIS?

Like the ModelBuilder of ArcGIS for Desktop to run simultaneous geoprocessing tools, is there any model builder available in QGIS or any other open source GIS software?
0
votes
1answer
151 views

Selection not displaying all results in QGIS

I have a point layer. Of which I have just selected 15 points from the attribute table manually and say show selected attributes. Of these 15 one point does not get highlighted the rest do fine. When ...
1
vote
2answers
2k views

How to save project with data source path as relative in QGIS?

Is their an option in QGIS to save the project with the data source being relative path. I Dont see the option here.QGIS Wroclaw1.7.3
2
votes
2answers
3k views

Can two polygon layers be merged in QGIS on a common id?

Can two polygon layers be merged in QGIS on the basis of a common id? Update: Ok , the dissolve tool works fine. But for instance lets say I have 10 polygons. 8 of them are together , so when ...
4
votes
2answers
5k views

How to use Distance Matrix tool in QGIS?

I have a point data set. Now there are cluster of points based on a field. So I take out one such cluster which has points with same field.I want to find distance between all the points in cluster and ...
11
votes
4answers
3k views

Is it possible to export GeoPDF from QGIS?

Is there any plugin for QGIS which would help me in exporting the map document as a GeoPDF ?
7
votes
2answers
1k views

How to animate raster time series using open-source GIS?

I have a bunch of rasters taken about 10 minutes apart, and I have a nice QGIS project that produces pretty enough maps of them. I'm wondering if there's a way to animate this raster series, with a ...
20
votes
3answers
4k views

How can I calculate the average width of a polygon?

I'm interested in examining the average width of a polygon that represents the road surface. I also have the road centerline as a vector (which is sometimes not exactly in the center). In this example ...
1
vote
2answers
926 views

How to get the altitude of the vector shapes from DTM raster layer?

I have a vector layer containing thousands of vector shapes/polygons and a raster layer with DTM. Every shape has its own OBJECTID in attribute table. I would like to get the altitude of every shape, ...
4
votes
1answer
438 views

How to display intersecting roads and create multiple labels for long roads in QGIS?

I am new to GIS and I am using Qgis 1.7.3 on Windows. Can any one please tell me how to display a map from line shapefile with these two characteristics: Roads are displayed with borders at the ...
3
votes
2answers
1k views

Is there an option to remove duplicate polygon labels in QGIS?

I would like to know if there is an option in QGIS labeling engine which would remove all the duplicate labels. My polygon layer contains a few features with same name. So when labeled it becomes a ...
4
votes
1answer
619 views

How to create zip code areas from point data?

I have a point dataset which has zipcodes for a certain region. This zipcodes have been marked on the basis of lat log collected. So each zipcode is repeated as it would be useful to show the region ...
26
votes
3answers
32k views

How to add Basemaps from Google or Bing in QGIS?

Like ArcGIS Desktop has the option of using basemaps from ArcGIS online, does QGIS have any such options?
1
vote
4answers
302 views

How to work with NREL data in QGIS?

I would like to use QGIS to display solar data from NREL. The file is supposed to provide solar radiation data of Colorado. However, I have some trouble to select this data in QGIS: In QGIS, I select ...
0
votes
2answers
530 views

How to remove overlapping buffer in QGIS?

I wanna know how to do this in QGIS: I've tried many ways, but still can't find the right solution.
4
votes
1answer
995 views

Why does QGIS's Clipper tell me “Computed -srcwin falls outside raster size” and how do I address it?

I'm trying to clip a heightmap to a small area that I'm interested in. When I attempt to use Raster > Extraction > Clipper I get an error dialog with the message ""Computed -srcwin falls outside ...
3
votes
1answer
497 views

Using QGis for an imaginary plane world

I created an own map for my p&p rpg group and now I want to transfer it into QGis. That's easy to make, but I'd like to have an own CRS for that map but don't know how to use the right proj.4 ...
1
vote
1answer
634 views

howto use MSYS with qgis?

I found a very nice tutorial at: http://sproke.blogspot.com/2012/02/mapping-software-for-84.html, which has some "unix-like scripts", which should be use with qgis. how can I copy and paste these ...
1
vote
1answer
323 views

Highlighting and exporting raster layer based on vector polygon

I am a Quantum GIS beginner. I have a set of adjacent polygons in a vector layer that is overlaid on a raster layer of OS StreetView OpenData. I want to be able to select each of these polygons and ...
3
votes
1answer
95 views

How to determine if feature A and B are located in the same room?

I have created a map using MapWindows like the following: A little explanation here, the is a map of an elderly home. The yellow boxes are room and the white rectangles inside the yellow boxes are ...
8
votes
1answer
420 views

What version of SVG should I be saving my images with for QGIS? Any particular options I should use/avoid?

I have a illustration in Adobe Illustrator that I'm trying to export as an SVG file and add to my map layout using the Print Composer of QGIS 1.7.3. When I add the image, I get strange artifacts that ...
3
votes
1answer
438 views

How to print to a specific scale with QGIS?

How can I print a map with qgis to a specific scale? E.g. I have a map of Austria (projection: albers equal area) and want a printout on paper at 1: 3000000? Thanks Kurt
2
votes
2answers
634 views

How to set up a plugin repository for QGIS?

I am working with python plugins for QGIS.I developed my plugin and created .zip file including my .ui,.py and resources files.In order to incooperate this plugin into QGIS i created .xml file ...
9
votes
6answers
1k views

QGIS users - What plugins do you consider to be essential?

The title says it all - vector, raster, geoprocessing plugins?
14
votes
4answers
2k views

What are data visualization and analyses pros/cons of QGIS over ArcGIS for Desktop?

Many of my colleagues use GIS on a very sporadic basis for simple data visualization and basic analysis (clipping, buffering, etc.) and I am hoping to transition these non-core GIS people to QGIS so ...
6
votes
2answers
6k views

Is there a way to manually place labels in QGIS?

Is there a way to manually place labels in QGIS? I have a map which has almost-duplicate labels in some places (e.g. E 1st St and 1st St) and I'd like to remove some of them. Also, I'd like to move ...
2
votes
1answer
353 views

Automatic script to update selected records in QGIS

I am after some advice on how to produce a script that a user can run in QGIS. The script will be run against newly created feature/s (Point, Line or Polygon) that will perform not only a spatial join ...
2
votes
0answers
136 views

How to change the QGIS help dialog?

I am working with python plugins for QGIS. I am done with my one of my .py file using python 2.5 and pyqt4. It is just help file for QGIS, which i changed. I wanted to incorporate the same in QGIS. I ...
4
votes
3answers
1k views

How do I add (and map) a non-spatial table to QGIS from SQLite?

I have an sqlite file from my Wigle Android app (wiglewifi.sqlite). It's not a spatial file, just tables with lat/lon and other data. I can add spatialite layers just fine, but cannot seem to find a ...
2
votes
1answer
875 views

JOSM vs QGIS/uDIG for road network editing and storage

My application needs to store a road network and provide editing functionality for that network (editing/updating/removing lanes, signs, traffic lights, speed limits info, etc.). I find JOSM tool to ...
1
vote
1answer
774 views

How do PostGIS layers in QGIS work?

I use QGIS 1.4.0 to import a layer which is basically a road network converted from an .osm file to a PostGIS database table by osm2pgrouting. I have skimmed through the documentation, but I am still ...
4
votes
2answers
6k views

Viewing .las format LIDAR data in QGIS?

Is there an easy path to visualizing this LIDAR data? I have QGIS, and some USGS LIDAR data in (.las) format downloaded from http://lidar.cr.usgs.gov/ . This means I have both the (.las) and ...
2
votes
1answer
397 views

A software architecture for viewing/editing roads and routes

I have a routing software module which uses PostGIS/pgRouting to calculate routes. The road network is generated from an .osm file with osm2pgrouting tool. I need to enhance the functionality of the ...
7
votes
3answers
4k views

How to delete multiple selected polygons at once?

I'm new at this, a novice at best. I'm using QGIS 1.7.3. I simply want to select a large number of polygons on screen and hit the delete key to delete them and resave the shapefile. Can this be done?
6
votes
3answers
5k views

How to add Raster legends in QGIS map composer?

Is there a plugin or method to add legends for raster layers (with a custom colourmap) as an item in the print composer?
1
vote
1answer
7k 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 ...