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

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0
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1answer
174 views

How to edit a group of selected features in QGIS?

I am dealing with a large number of planning units across a very large study area. I am selecting a number of features using the advanced search in the attribute table, and would like to edit them ...
0
votes
1answer
127 views

QGIS - Unable to get OSM data on re-opening project

I have now successfully got OSM maps to import as I would like, but if I save the project then later re-open, I always get a bad layer message and I have to reload the OSM once the project is open. ...
2
votes
1answer
834 views

How to query attributes cross-table in QGIS?

is it possible in QGIS to query a layer with data from another layer? And if so ... how is the syntax for that? Usecase: I have a lot of image-position points and a lot of monitoring sites. I would ...
7
votes
1answer
275 views

Jitter or Randomise Points in QGIS

Occasionally I'm asked to plot points that relate to sensitive data items. I would quite like to be able to add a varying level of random jitter to points when plotting so that point density is still ...
4
votes
3answers
930 views

How to split features?

I would like to split a shapefile in qgis according to how the polygons overlaps. Don't know how to though? See pic for explanation:
1
vote
2answers
2k views

Export georeferenced image into Google Earth

I have created a georeferenced image as instructed in this fine tutorial: http://qgis.spatialthoughts.com/2012/02/tutorial-georeferencing-topo-sheets.html Now I would like to get this image into ...
1
vote
2answers
955 views

Setting OSM map data to aerial view in QGIS

I have just started playing around with my first GIS package, QGIS. I have successfully used Ordnance Survey Vector data to create maps but when I try importing maps from an OpenStreetMap export it ...
2
votes
1answer
390 views

How to use ECWP protocol with QGIS?

Is there a way to retrieve remote data through ECWP protocol in QGIS? I've read that .ecw files can be opened with QGIS, but haven't found anything concerning this particular protocol and QGIS.
2
votes
1answer
2k views

Why is my .prj file not being read by QGIS?

First off, I am new to GIS. I am using qgis (1.8.0), and have been given a shapefile containing .shp, .prj, .shx, .dbf, however qgis will not load the .prj file stating an invalid data source. ...
7
votes
1answer
222 views

Why is there a black hole in the Heatmap?

After running the Heatmap tool in QGIS I like to color the geoTiff according to my wishes. Using Psuedo color works fine, but it leaves me with no options, as type of color scheme or transparancy on ...
1
vote
1answer
362 views

How can I move diagrams?

Is there a way to locate diagrams and move them wherever you want in QGIS 1.7.4/ 1.8.0? I created a pie chart under the tab "diagram". I can mark those diagrams with a green box and move them via the ...
8
votes
2answers
2k views

How to compute parameters for QGIS Affine transformation?

I have a vector floorplan (DXF) that I've added to a blank project in QGIS using the Dxf2Shp plugin. I've been reading tutorials and StackExchange threads, but I can't seem to find out how to ...
1
vote
3answers
628 views

How to start QGIS after building & install on ubuntu 12.04 64bit?

I am a newbie here. I am running ubuntu 12.04 64bit, and build after the instruction, but i don't know why can not launch qgis. Seem i successfully build $ install it. below is the linux shell: ...
3
votes
1answer
2k views

Why does QGIS show too many labels per feature?

When i check to label polygon feature, one out of a total five polygons shows like 10 labels on top of it. That particular polygon is only one polygon, represented by one row in the table, so i dont ...
2
votes
1answer
113 views

Are there any mirrors for QGIS documentation? [closed]

I have tried several times today (July 30, 2012) to connect to www.qgis.org (to get the online documentation). The site seems to be down. Do you know if there is a mirror to obtain the Lisboa (1.8) ...
6
votes
5answers
9k views

How to export/save a layer composition to GeoTiff?

I want to export/save a QGIS composition of raster/vector layers to a GEOTIFF or ECW raster with high resolution (20 000 * 20 000 Pixel).
5
votes
2answers
1k views

GeoTiff size - what to do?

I have a whole series of GeoTiff tiles, each one about 250mb in size, in total just over 90gb. I want to be able to display these as a wms into QGIS to 20+ GIS users and in the end make them into a ...
2
votes
3answers
3k views

Problem with spatial reference system / shapefile projection

I am new to using QGIS and having some problems getting some shapefiles to project correctly. I am using publicly available shapefiles for New York City municipal boundaries found here: ...
8
votes
2answers
1k views

How can I create random points along a polyline in QGIS?

I am trying to create random points along a polyline shapefile in QGIS. Basically, like the 'random points' tool in 'research tools' but for polylines instead of polygons. I have tried converting ...
1
vote
0answers
368 views

Stats problem, QGIS heatmap [closed]

I am new to QGIS 1.8 and have been trying to make a heatmap. From what I can tell, the reason I am not getting the results I want is that the max value of the raster is erroneously measured at 2. ...
3
votes
2answers
4k views

How to split a line at point positions?

I am a rooky with QGIS and i am stuck from a basic problems. I have a polyline and i have some points (2) on the polyline. I would like to know if there is a tool or script that i could use to ...
3
votes
2answers
3k views

How to fix “The entry point for the procedure sqlite3_open_v2 cannot be found in the dynamic link library sqlite3.dll”

Translation: Hello, I have a problem installing version 1.0.8. The following error message appears: The entry point for the procedure sqlite3_open_v2 cannot be found in the dynamic link library ...
10
votes
1answer
7k views

Open a GeoJSON file with QGis

If I have a GEOJson file, for example a file named test.js with inside the following: { "type": "FeatureCollection", "features": [ { "type": "Feature", "geometry": {"type": "Point", "coordinates": ...
1
vote
1answer
140 views

Where is Quick Print for QGIS 1.8?

Just installing Qgis 1.8 Lisboa, i can't find "Quick Print" Extension. Any idea where to catch it again ? Thanks Jean
7
votes
1answer
2k views

Using PostgreSQL with QGIS and ArcGIS?

Is it possible to use PostgreSQL with QGIS and ArcGIS? i.e. one database for different clients. Is it anything that I have worry or any problems to use the DBMS from two different software? I know ...
2
votes
1answer
2k views

How to export vectors from QGIS to MapInfo?

I am trying to save some vector lines that I made in QGIS (1.8 Lisboa) to a format that can be added to MapInfo Professional 6.0 (ancient version I know..). When I save the vector to a Mapinfo ...
5
votes
4answers
4k views

Advanced colour palette for raster data

I'm working with satellite date namely chlorophyll and sst. Each geophysical parameter generally has standard colours to represent them. I'm importing geotiffs into Qgis and I'm having difficulty ...
2
votes
1answer
463 views

polygonize and raster tools [closed]

ok simplest question i have asked i think. but im a running QGIS 1.7.4 and there are no other tools in the dropdown menu other than raster calculator. I have seen in a lot of online demos tools below ...
2
votes
1answer
187 views

QGIS Console error Libgrass

Just installed QGIS 1.8. on Mac OSX Installed GSL Install GDAL 1.9 Complete Installed QGIS keep getting this console error message in QGIS. Failed to load ...
1
vote
0answers
249 views

Problem using addVectorLayer() in Qgis

I am confused a bit, using addVectorLayer() in QGIS plugin. I want to add and display a vector layer, directly when QGIS opens. Hence I am using addVectorLayer() in _init_() function of my plugin. ...
0
votes
2answers
543 views

how to create gis like Uster?

I downloaded qgis, geoserver, openlayers, ext, geoext, qgis-web-client and osgeo. And i have map shape files. i would like create website like this site. i need help. can you send tutorial links thank ...
5
votes
2answers
5k views

How to create a lat/lon grid in QGIS?

I'm using QGIS. How can I create a shapefile consisting of a grid 0.5° latitude and 1° longitude in size?
0
votes
1answer
472 views

How to dissolve based on the overlap of polygons in the input file?

I am using ArcGIS 9.3/10 to dissolve few hundreds of overlapping polygon features. Now, I am seeing that Arcgis is not able to do dissolve for 5000 polygons. Generally, I used to dissolve ...
3
votes
1answer
1k views

Where are decoration (scale bar, etc) plug-ins in QGIS 1.8?

For QGIS 1.8 what happened to the "Decorations" (North Arrow, Scale Bar, etc) plug-in (for the canvas, not composer)? Thanks.
0
votes
0answers
165 views

How to build QGIS with Python on Redhat?

I'm attempting to run QGIS on Redhat 5 64 bit architecture. Version of Python is 2.4.3. Version of QGIS is 1.7.4 (wroclaw). When I run qgis, the splash screen appears, followed by a QMessageBox that ...
5
votes
1answer
786 views

Identify Polygons on raster image

I have OS street view mapping as raster images. Is it possible (without the obvious of tracing each dwelling) to identify all polygons on each tile. To clarify, My ultimate aim is to produce a ...
12
votes
2answers
5k views

How to create a new empty vector layer programmatically?

I am new to python and QGIS. I have looked at a few tutorials of python scripts for QGIS. All of them create new vector and raster layers with some existing data source. eg. shapefile or geotiff or ...
3
votes
1answer
1k views

legend groups and layer position/order qgis 1.8

I'm tring to programmatically create layer sequence also using groups. Simple python code: layer = QgsVectorLayer("004cp000.shp", "004cp000", "ogr") QgsMapLayerRegistry.instance().addMapLayer(layer) ...
0
votes
0answers
94 views

why are split-lines saved in the attribute table? (qgis 1.7.4)

A few months ago I splitted some lines in a shapefile with official roads because they are not accessible anymore. Now I loaded that file again into my project and the splitlines appears. Because I ...
7
votes
1answer
716 views

How to adjust the granularity of a heat map in QGIS?

Not sure I am using the correct terminology here, so I have tried to describe my problem in detail. Please edit as needed. I have a layer of points, a layer of roads and a heat map in a raster layer. ...
8
votes
1answer
3k views

How to fill gaps in SLC-Off Landsat 7 ETM+ Images with QGIS?

Explanation of the problem: On 31 May 2003 the Landsat 7 Enhanced Thematic Mapper (ETM+) sensor had a failure of the Scan Line Corrector (SLC). Since that time all Landsat ETM+ images have had ...
3
votes
2answers
2k views

How to calculate LS Factor of Watershed for RUSLE Calculation?

I managed to get subbasins for my catchment (7 km^2) with their areas but I haven't figured out how to get the LS factor (see Revised Universal Soil Loss Equation) from it. I have the vector file ...
2
votes
3answers
4k views

How to convert from EPSG:4326 to WGS84/UTM 32U?

I am unable to convert from the project's coordinate system to a different one using QGis 1.8.0. I have a .shp file with a certain coordinate system information (WGS84 EPSG:4326 according to qgis). I ...
1
vote
1answer
132 views

Is there something like SQLselect from MapInfo in QGIS?

I am a user of MapInfo that will need to adapt increasingly to QGIS. Is there something like "SQL select" in MapInfo which allows me to easily query between two tables or spatial queries? MapInfo ...
2
votes
0answers
678 views

How to change feature's geometry?

Hy, I'm creating my layer like this: crs = core.QgsCoordinateReferenceSystem(4326, core.QgsCoordinateReferenceSystem.EpsgCrsId) uri = "Polygon" uri += '?crs=' + crs.authid() uri += ...
1
vote
1answer
793 views

Is getting wrong attribute values from a feature in qgis

I make two polylines features(in my example both consists of two points) with the add feature tool. Then I (with code) add some attribute values on the first feature, then changes the geometry of the ...
1
vote
3answers
843 views

Deleting columns from joined attribute table in QGIS

After joining the attribute tables from two layers, I have a lot of duplicate columns on my table, making it hard to read. However, even when in "edit" mode I am unable to select and delete columns. ...
2
votes
1answer
72 views

Which class should I use to work with vector layers?

I'm doing different operations on vector layers. Kindly suggest which class should I use for vector layer i.e QgsVectorLayer or QgsVectorLayerDataProvider.
7
votes
5answers
16k views

How to install Openlayers plugin on Qgis 1.8?

After having installed Qgis 1.8 i am not able to find the Openlayer Plugin. In "the old days" I know I was supposed to check "add 3rd party repositories", but that button has disappeared? I tried ...
0
votes
1answer
682 views

Qgis install can't find Gdal framework (Mac OS X 10.7)

After having installed Mac OS X 10.7 I can't install Quantum Gis as it maintains that I have not installe the GDAL Framework, which I have done (several times). Have anyone experienced the same ...