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

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10
votes
6answers
1k views

How do I make a heat or Choropleth map that uses polygons in QGis?

I've been playing around with the heatmap plugin for QGIS and I am wondering if it is possible to make heatmap with using a similar plugin/tool that uses polygons as well as points? I would like to ...
4
votes
1answer
132 views

How to aggregate point measurements in areas?

I have a shapefile with the geographical boundaries of towns in a specific region; then i have a csv file (with xy coords) with a lot of measurements about pollution in this region. I'd like to have ...
1
vote
2answers
379 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 ...
3
votes
1answer
145 views

How to get the “absolute value” of a raster cell in QGIS?

I have a raster map (-100 to +100) and I need to get all the minus values as absulute values (-100=100; -99=99...). How can I do this? Is it something like reclassify?
-4
votes
1answer
79 views

Geocodin process in open source GIS tools [closed]

I want to do geocoding with open source gis tools , is it possible? if then tell me the solution? I have my village attribute data with me like addresses and contact information of persons in every ...
2
votes
1answer
347 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
votes
1answer
313 views

Could you suggest software to draw a cross section, companion to QGIS?

If you use GIS systems, what software do you turn to when there is a requirement to draw a cross section? Ideally a workflow that includes QGIS. Typically there are some points which will coexist in ...
5
votes
2answers
767 views

How to batch import GDAL supported raster files into GRASS?

I am trying to import some GDAL supported raster files into a binary raster map layer using the r.in.gdal module from QGis Grass tool. As I have multiple files to import, I would like to batch import ...
5
votes
1answer
622 views

How to get pixel size/cell size of raster layer?

After much searching, I've still not been able to figure out how to perform what seems like a simple function: I'd like to get the pixel size/cell size of a raster layer using PyQgis. Is there any ...
10
votes
4answers
1k views

How to buffer in pyQGIS?

I'm looking for some examples to do simple python scripts in QGIS. How would I do a buffer analysis on a dataset? I can't seem to find much in the manual and QGIS python that quite matches the Esri ...
13
votes
4answers
2k views

Are there tools to directly import QGIS projects into Tilemill?

Now that there is a tool to convert an MXD to Tilemill, one must then wonder if the ability to open QGIS documents in Tilemill will ever exist.
5
votes
1answer
679 views

How to load mdb geodatabases in QGIS for MAC?

I've been unsuccessfully looking for a way to add data from a .mdb geodatabase into QGIS for mac. Using the add vector layer, .mdb is not available in the filetypes, and in the database connection I ...
4
votes
1answer
288 views

NAD83 and NAD83 State Plane

I'm struggling with a projection question. I have some data in California State Plane and am trying to align a NED with NAD83. I thought these would just natively align, but they don't seem to ...
5
votes
1answer
300 views

How to calculate a standard deviation across multiple raster layers?

I have 15 raster layers. Each one shows accumulated precipitation (rainfalls) for the month of April for the same US state during a given year. So, I cover the period from 1997 to 2012. I would like ...
2
votes
0answers
212 views

Generate QGIS maps automatic after updating an Access 2010 or Filemaker Pro 12 database

I want to develop a database which consist an interaction with QGIS. After updating the data in the database I want to push on a button and start a process in QGIS. After finishing the process in QGIS ...
3
votes
1answer
425 views

Why are the features in my memory layer not displayed?

I am trying to create a memory layer, I followed the directions from the page below but no points appeared on my map. First I tried typing each line into the python console and I also create a plugin ...
4
votes
2answers
1k views

TIN Creation from 3D Contour File

I'm currently trying to import a 3D contour file into a Quantum GIS project. My question is, how can I export the DXF file from Microstation with height information? I already have imported it to the ...
2
votes
1answer
373 views

Creating a quality raster map in QGIS?

I've got 2 raster maps (both with the same values: 0-100). After calculating the average I need to know how precise the map is. Is there any tool in QGis? I try to explain my problem in another ...
3
votes
2answers
72 views

How to make a copy of a temp raster in QGIS?

I have a temp raster (saga raster) file. How can I make a copy of this file (like "save as")? Thank you!
1
vote
0answers
76 views

Is there a way to make a qgis project only editable by me

In QGIS, currently Lisboa 1.8.0 is there a way to make it only editable by me. I want to set up projects for each client on the network, so when all the files are on the network and the program and ...
3
votes
3answers
199 views

How can I draw squares in PostGIS layers at different angles?

I am trying to draw two squares on a 45-degree angle and then merge them using PostGIS to edit. QGIS can draw squares but only on a perpendicular plane (eg, 0, 90, 180), and I need to be able to draw ...
4
votes
1answer
545 views

Why don't my polygons from MSSQL2008 display in QGIS?

I have imported a polygon shape file in MSSQL2008 using Shape2SQL loader without any issue. When I import the loaded polygon file in QGIS, I can't see it ! When I import other point or line features ...
1
vote
1answer
662 views

Problem merging two rasters in Qgis

I have two rasters in Geotiff, same CRS. I tried to merge them and I have this error code ERROR 4: `C:/Anita_Tepoztln/Rasters/e142.tif' does not exist in the file system, and is not recognised as a ...
11
votes
1answer
352 views

How to associate polygons with the nearest point on a point layer? (Or … how do I assign a postal area to a salesman?)

I have a polygon layer of postal code areas and I want to use them to create sales territories based on where our sales people are based. So I assume that I need to work out for each of the polygons ...
2
votes
1answer
819 views

Rendering GML in QGIS 1.9.0

I have a set of GML geometries (see here), which I try to load in QGIS. The set contains both points and polygons, but when loaded into QGIS, only points are shown. I tried to follow this thread, but ...
6
votes
2answers
279 views

How do I compute v.kernel maps in less than 16 hours?

I am using the GRASS GIS 6.4.2 bundled with QGIS 1.8.0, using a PostGIS dataset exported via v.in.org.qgis from QGIS, to create kernel density maps. The layer has 738,288 points. My problem is the ...
3
votes
1answer
132 views

Creating rasters?

I am doing my masters in archaeology, but have used GIS for some time now, however this is my first attempt at generating and using rasters. I appear to have been successful for some, but not so well ...
0
votes
0answers
142 views

Why are my combo boxes not filled with a list of layers?

I am developing a Qgis plugin (layer_gui) and I am having a problem with populating the list of layers. When I first run the plugin my combo boxes are not filled with a list of layers, I have to ...
8
votes
1answer
2k views

Will there be an iOS version of QGIS?

I saw that QGIS now works on Android, any chance there will be an iOS version?
4
votes
2answers
679 views

Spatial query of raster data

I have population distribution data as a raster layer and exposure contours as vector (polygon) layers. What I'd like to do is use the vector layer to estimate the population indicated from the raster ...
2
votes
2answers
308 views

projection issues from ArcGIS to Qgis

I am pretty new to ArcGIS and Qgis. I have loaded some geometry data in Qgis from my postgres database, then I have also loaded the same data in ArcGIS. Then from ArcGIS i have created a shapefile ...
1
vote
1answer
315 views

Why does ftools' difference tool fail?

I have an area polygon with rocks on it i want to use difference to map the soft (ground, not rocks) cover. to do that i try using the (ftools) vector>geoprocessing>difference getting an empty ...
4
votes
1answer
51 views

Is there a QGIS mailing list that only announces new releases?

Is there a mailing list for qgis that announces only new releases / new binary packages? Thanks.
2
votes
1answer
267 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 ...
5
votes
2answers
3k views

Can I export a polygon shapefile to a Garmin device?

I want to export the boundaries of a parcel to my GarminMap 60CSx. I downloaded a parcel map from the county, and I want to use it to walk the perimeter. Does the .gpx format support polygons? Or is ...
3
votes
0answers
96 views

How to digitize 90 degree angles? [duplicate]

Possible Duplicate: How to create polygons with straight lines and right angles in QGIS? In QGIS 1.8 is there a way to digitize buildings etc. with perfect 90-degree angles, Or, edit a ...
3
votes
1answer
249 views

Does QGIS DB Manager plugin lock PostGIS transactions?

I do most of my geospatial analyses in PostGIS 2.0 using PgAdmin III. I use QGIS 1.8 for visualizing my data but also for querying my database using the DB Manager plugin. Sometimes (quite often ...
4
votes
3answers
643 views

How to create an intensive map of Russia using QGIS or any other software?

I am trying to create an intensive (heat) map of Russia. I have an excel sheet of 36 Russian regions and their corresponding values. I know that there were similar questions: How to create a map ...
4
votes
2answers
1k views

QGIS exporting huge SVG [duplicate]

I'm having trouble exporting an SVG(or a PDF for that matter) from the QGIS print composer. I have a relatively simple map that should, when exported as an SVG, be maybe around 1MB in size, tops. But ...
1
vote
0answers
24 views

Where can I find the 1-band color raster plugin for QGIS? [duplicate]

Possible Duplicate: How to install “1-band color raster color table”? I'm searching for the 1-band color raster plugin. What is the essential repository? Or is there another tool for ...
3
votes
2answers
2k views

How to add points in degrees + decimal minutes to QGIS?

I try to add geocaches with x,y coordinates in a xls-table to qgis and convert to shp.file. Usally geocach-coordinates are like this: N 51° 29.440' E 011° 56.430' (WGS84) (in german its called ...
7
votes
4answers
1k views

Calculate polygon field based on neigboring polygon attribute

I have a vector shape with many different sized polygons each possessing an own class name (for instance "houses", "houses with offices", etc ...) I want to assign a new field to each polygon ...
8
votes
4answers
2k views

How to modify single Pixel values in QGIS?

I would like to modify a raster (pixel values) in QGIS. The plugins "value tools" can easily provided me with the value of the pixel of my raster. However I know know how to modify it. I have found ...
4
votes
1answer
4k views

Convert Shapefile to MySql

I have used Grass GIS imported a .shp file; I now want to export this file to MySQL. I understood that MySQL will contain the function of all three the files necessary in a Shape file system (.shp - ...
3
votes
1answer
598 views

Which parameter values should I use with QGIS Heatmap plugin?

I've read all the posts and docs about the heatmap plugin but can't seem to get it to work. The map is the size of the United States and has a little over 2000 points. I've tried small radi (1 ...
2
votes
1answer
261 views

QGIS & GeoTIFF clipping Error “-srcwin 5897 137 0 0 falls outside raster size of 11083x4158 or is otherwise illegal.”

I'm trying to clip a GeoTIFF file and unfortunately I'm getting the following Error "-srcwin 5897 137 0 0 falls outside raster size of 11083x4158 or is otherwise illegal." From another post ...
2
votes
1answer
70 views

Are there any document icons for the qgis mimetype?

In a default Ubuntu install (QGIS 1.8.0) no document icon is associated with the mimetype 'application/x-qgis-project'. As a consequence every saved QGIS document is interpreted by the OS as being a ...
4
votes
0answers
306 views

How to automatically format the legend labels? in QGIS

I have to do 10 maps (for a start) with "style" -> "graduate" with quantile mode. I need to format the label of the different ranges so that the legend looks comprehensible: Instead of having 1.0000 ...
19
votes
2answers
8k views

How to convert .shp into .gpx using QGIS?

I'm newbie using QGIS. I would like to convert .shp into .gpx. So, using Qgis, I open my shapefile and I tried to "save as" gpx but it gives an OGR error: creation of field ObjectId failed (OGR ...
1
vote
1answer
1k views

rpy2 installation ERROR “Tried to guess R's HOME but no R command in the PATH”? [closed]

I tried to install rpy2 (pip install rpy2). I want to use the SDAPP4 extension with QGIS (QGIS shows up the message missing rpy2...). The system tells me always the same error: Tried to guess R's HOME ...