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

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How does Flow Mapper Plugin work?

I downloaded the Flowmapper plugin for Qgis and I can't seem to find any information on how it is supposed to work... Also the text seems to cut-off and not fully showing for the input fields so I'm ...
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votes
2answers
185 views

Using field calculator to delete specific contours

I have 3 contour shapefiles with 25m, 50m and 100m equidistance. Now I want to delete in the 25m-shp-file every **50m and **00m contour and in the 50m-shp-file every **00 contour. How can I show them ...
5
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1answer
1k views

Distance Matrix tool in QGIS. How to get result in metric? [closed]

I'm trying to calculate the distance between points in layer with distance matrix tool. And keep getting strange results no matter what. Like this MASTER ------------SLAVE ---------------- DISTANCE ...
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2answers
818 views

Why do I get “Failed to transform” when reprojecting from WGS84 to Google Mercator?

I am attempting to re-project a vector shapefile from Natural Earth, following a qgis tutorial. Another user reported this error, but a solution has not yet been reported. Given this post, and the ...
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1answer
1k views

How to reproject a raster in QGIS?

I am a history teacher and I like to make my own maps (I can never find exactly what I want). I am using QGIS 1.8 and Natural Earth data. I want to reproject their cross-blended hypso rasters into ...
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1answer
1k views

Remove duplicate nodes in QGIS

I am trying to create a polygon feature from an enclosed line feature using the Geometry Tool: Lines to Polygons. When I do this, I get several spikes with the newly created polygon. I then run the ...
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2answers
1k views

Where can I get information on QGIS beta versions?

While searching for information on some qgis functionality on the web, i noticed several times, people using version 1.9, however this version is probably some beta (or so i thought) but i cant seem ...
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2answers
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How to compare two DEMs and show their difference?

I want to compare my DEMs (ASTER GDEM2 and SRTM4.1). I know, that the GDEM has some extreme "holes" with totaly wrong elevations (I found 3 of them in my working area). Now I need to know, if there ...
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3answers
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Producing singlepart featureclass with unique IDs for each spatially non-connected polygon?

What is the best method to convert a singlepart shapefile (i.e. one record that contains several non-connected polygons) into a mutlipart shapefile? For clarification the original question asked how ...
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1answer
1k views

Why do TIF loaded into PostGIS lose their colormap?

I have successfully loaded a TIF image (using raster2pgsql) into my PostGIS 2.0.1 database. I can load the raster image into QGIS and it displays in the correct space. However, it has lost all colour ...
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1answer
3k views

Is there a way to export QGIS layers to KML?

has had anyone had any luck with the new experimental plugin qgis2kml? I keep getting the error msg layer : format not yet supported I had a look but the author has not provided any documentation, ...
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1answer
568 views

How to handle spatial join 10 chars field name limit?

When I try to perform a spatial join between a point and polygon file, I get a notice saying spatial join will not be performed because following field names exceed 10 Characters. Kindly help to ...
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467 views

Map is missing when I “export as image” via print composer [closed]

I have point data on a vector layer that prints accurately via print composer (when I "export as image"), however my map below either does not show up or shows up at an incorrect scale. I used ...
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1answer
3k views

How to do Kernel density analysis in QGIS 1.7?

Do someone have some suggestion? We would like to tray Kernel Density analysis as we did with ArcGis using QGIS?
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5answers
5k views

Workflow for DXF interchange with QGIS

What is the best method of importing/exporting dxf files with QGIS ? I work in an engineering field and we use CAD and specialist design programs, and often go through several iterations during a ...
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1answer
1k views

How can i delete multiple nodes, for a polygon, with Quantum GIS?

I know how to select a single node and delete it. I can also click-drag to select MULTIPLE nodes. But if i click delete, only one node (from the higlighted list) is removed. Can I delete all the ...
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3answers
2k views

How to find line length in QGIS while editing?

I am using QGIS (before, I used ArcView). I would like to know if there is any way during the editing phase of a vector (line or polygon) to know the length of the line (total and partial) that is ...
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6answers
922 views

Southern hemisphere projections for Landsat upsets GRASS

Hi All does anyone have the last word on why Landsat scenes don't project in the southern hemisphere. This causes no end of trouble in GRASS, less so in QGIS. What I mean is, take an original scene ...
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2answers
579 views

Distribute points respect to features using Quantum Gis

I want to know if there is any tool to make points with respect to selected features in a theme? Using: vector, investigating tools, regular points you can do it but not with respect to a selected ...
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2answers
105 views

QGIS Function editor calculate area after transform

In the QGIS function editor, it is possible to transform geometry using transform(geometry,'EPSG:xxx','EPSG:yyy') - however there isn't an area() function to recalculate the area of this. The reason ...
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2answers
97 views

Is it possible to copy a graduated scale from a polygon to a point layer in QGIS?

I have a polygon layer (represented by cells) and a point layer. I've used the graduated symbology with the polygon layer. Now I'd like to export this graduated scale to the point layer. The field of ...
4
votes
1answer
547 views

How to compute Walking and Cycling Isochrone maps using QGIS & pgRouting?

Just installed QGIS as I believe I should be able to produce walking and cycling isochrones from a specified point. I have done this pretty easily before using ArcMap, however, I am really struggling ...
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3answers
116 views

QGIS Composer thematic map : one (png, pdf, etc.) map per feature type

I've got a shapefile that contains thousands of features that can be group by categories. These features are sometime located in the same place so they overlap. An example of the content of my ...
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1answer
121 views

QGIS equivalent to ArcGIS Aggregate Polygons?

I am looking for a tool in QGIS 2.40 that performs the function ArcGIS refers to as Aggregate Polygons. Basically it takes a group of polygons within a specified distance and creates a concave hull ...
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1answer
122 views

In which way is height information stored in a DEM?

I'm struggling with different DEM data, because I don't know how to convert the height information in meters. When I load ASTER and SRTM tifs in QGIS, it shows me the spectrum of the grayband (0 to ...
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2answers
897 views

How to add Georeferenced PDF as layer to QGIS 2.0?

I have some georeferenced pdf's that I would like to open in QGIS. I have read that GDAL version 1.8 and higher will support pdf, and I have GDAL 1.10 installed with QGIS 2.0 on Windows 7, but when I ...
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1answer
729 views

Is there a way to run a python script on opening a QGIS project?

I have a .csv file containing financial data which is generated on a regular basis outside QGIS. Then I want to create a PyQGIS script that will add the .csv file as a layer in my project. (The idea ...
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2answers
168 views

How to tell QGIS where to start marker line interval?

I want to tell QGIS where to start with a marker, like: use 3 markers, start at positions 0, 2, 4, and apply an interval of 12 to each marker. However, after searching for hours, I haven't found a ...
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0answers
103 views

Distribute QGis plugin which depends on certain Python packages

I developed a plugin for Qgis which depends on some Python packages. On Linux and Mac, this is not really a problem because I can easily install them with the system pip command. Windows is another ...
4
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1answer
686 views

Python error with open layers plugin QGIS 2

I've been using QGIS for a while but since using QGIS 2 the OpenLayers plugin doesn't work for me on my home pc. (However, I have installed the same version at my workplace with success.) I have ...
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1answer
385 views

Historical U.S.G.S. Georeferencing

I have downloaded a historical USGS map that is suppose to be a geoPDF. My understanding is that QGIS cannot directly read geoPDF's. I have not had any luck in converting it to a geoTIF in order to ...
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216 views

QGIS does not read ESRI Geodatabase correctly

I have a geodatabase from the EPA that does not seem to me reading correctly with Quantum GIS. QGIS Version 1.8.0 (Lisboa) and GDAL/OGR 1.9.2 When I open the attribute table the first two columns ...
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1answer
479 views

QGis Save Raster as Rendered Image

In QGIS 1.9.0 Master, when you right click on a raster in the Layers Panel and select "Save As", you can select the output mode to be "Raw Data" or "Renedered Image". When selecting the Rendered ...
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1answer
126 views

Determining size of grid cells created by vector grid tool of QGIS?

I am working with QGIS 1.8.0 and Im making a vector grid on a map. Does someone know how big are the squares if the grid settings look like in the picture?
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2answers
817 views

How to average values in a point layer with respect to polygon layer in QGIS?

I am new to GIS and have the following problem: I have 2 layers: a point layer with a column that contains numbers (pollution index from specific measurement point) and a polygon layer with different ...
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1answer
275 views

Can county level info be brought into a map?

I have a csv file of Clovis projectile points that were recorded only with the county in which they were found, no coordinates at all, no shapefiles. Is there a way to bring these into a state map ...
4
votes
1answer
420 views

How to measure the distance of multiple points to a line

I have two shapfile in QGIS to which I am trying to find the distances between. I have a shoreline which is a vector line and then I have hundreds of data points in the ocean. What I am trying to find ...
4
votes
1answer
1k views

QGIS Zoom from python console

What are the commands to apply all types of zoom (full, on selected layer, etc.) in python console? I'm searching both on pyqgis cookbook and API documentantion, but I'm not finding anything ...
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2answers
532 views

Can't select layer to upload to GPS

I'm trying to upload a vector layer to my Garmin GPS unit. I've saved it as GPX (WGS 84); opened the GPS Tools dialogue in QGIS 1.8; selected the "Upload to GPS" tab; and clicked on the "Data layer" ...
4
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1answer
3k views

How do I get and install the latest version of QGIS in Ubuntu?

I'd like to get the latest 64-bit dev build of QGIS on my Ubuntu setup. How exactly do I go about it? I assume it's some kind of arcane terminal command...
4
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3answers
2k views

How to install QGIS 1.8 plugin Georeferencer?

My question is about qgis 1.8 georeferencer plugin. I installed the new version qgis 1.8 but I don't have the georeferencer plugins, how do I install it? I used the georeferencing plugin with QGIS 1.6 ...
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4answers
2k views

What are the advantages either way between GML and Shapefiles?

After a good start many months ago of getting into GIS through QGIS, I had to drop what I was doing and did not touch it for quite some time. I am now able to get back into it and have a need to load ...
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2answers
530 views

QGIS saving analysis output as Postgis table

i am using QGIS and Postgis together. I can load data in Postgis and than i import it to QGIS. But i am trying to save an analysis output (example: buffer analysis, voronoi polygon or SEXTANTE ...
4
votes
1answer
772 views

Join attributes by location

I am trying to join multiple records that occupy the same location (polygon centroid) and have tried using the join by location plug-in but have found this does not work for me in this case as I have ...
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3answers
2k views

Summing attributes intersected by under a radius

Apologies - new user. I am working with QGIS on Mac OS X and with shapefiles downloaded from the US Census Bureau that show population data by state and by county. How do I: select certain points ...
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1answer
1k views

Unit of $length in QGis Field Calculator

I'm calculating field of various features in my shapefile using QGis. I'm getting some sample length as 0.134914579766986. I want to know in what unit (eg: meters, km etc) is the above value ?
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1answer
839 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 ...
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1answer
1k views

Is there a silent installation command without the desktop shortcuts? [closed]

I installed QGIS with Microsoft SCCM 2012 and I want to make a silent install without desktop shortcuts. I managed to do a silent install with / S but I found no s command to delete desktop ...
4
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4answers
999 views

TIN interpolation crash in Qgis

I have problems using the function TIN(linear) interpolation in Qgis. The program crashes when larger areas is interpolated. Map properties: vector map, Geometry typ = Point, features in this ...
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1answer
544 views

Why are the polygons in my GML not rendered?

I tried to view GML files from download services ( http://services.cuzk.cz/gml/inspire/cp/epsg-5514/ ) and I have a problem with viewing of polygons from layer "CP:CadastralParcel". This Layer ...