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

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7
votes
3answers
4k views

How to calculate raster statistics for polygons?

how can I calculate sums, averages etc of raster-points (multi-band) per polygon of a vector-layer. I was told that this is called "zonal statistics". I tried that with QGIS first. There is a way to ...
1
vote
1answer
258 views

Is there any support for Rasterlite in the Android QGIS?

Is there any support for Rasterlite databases in the Android port of QGIS? I have tried adding a raster layer as I would on desktop QGIS but there are fewer GDAL file formats listed. Is this ...
3
votes
2answers
755 views

Generate non-overlapping shapes from a buffer

I have a collection of points, and I need to generate shapes around these points. Let's assume that these points are locations of offices and that the shapes are the 'area of responsibility' around ...
3
votes
1answer
182 views

How to create a point layer from a one-to-many join?

I have two layers: One with geographical coordinates containing every address in the county and a unique identifier. The second contains a list of incidents with the unique identifier from the ...
0
votes
1answer
410 views

shapefile and multiple lines of census data QGIS [duplicate]

Possible Duplicate: How to join multiple records to single feature? I am hoping to be able to link in the attribute table more than one line of data from a census entry per polygon. for ...
7
votes
1answer
407 views

What are the rules that the Gdal rasterize function follows to allocate a value to a cell?

How does the rasterize tool decide which value to represent when a cell covers an area which inclueds different values? I need it in this case for polygons but would like to know for lines and points ...
8
votes
0answers
508 views

How to define Winkel Tripel in proj 4.8.0?

I have QGIS with proj 4.8.0 installed. I'd like to add Winkel Tripel projection which seems to be defined as +proj=wintri But that definition string does not work. Is this a bug in my proj version, ...
1
vote
1answer
313 views

How to get a legend for a WMS layer and search in it?

How to bring legend and search for WMS layer in QGis? I can see the WMS layer in Qgis but can't make any legend for identifying feature types and searching in WMS layer?
2
votes
2answers
419 views

Which labelling tool/engine in QGIS will be supported in the long term?

Why does QGIS appear to have two labelling tools? (Note this is not new and old symbology, but that...) there are two different GUIs, one in the toolbar (which gives the Data Defined Settings option) ...
2
votes
3answers
862 views

How to search feature in Qgis?

How is it possible to search feature on Qgis? I have lots of points with Id. Is is possible to search points using ID? Update: I'm looking for a solution that centers the map to that point.
1
vote
0answers
603 views

SDA4PP not found? How to do Kriging in QGIS?

I need to make kriging analysis in QGIS (v1.7.4). I found out, that it should be a part of SDA4PP plugin, but I just couldn't find it in any repository (even third party). It looks, like it just ...
3
votes
2answers
388 views

How to get the layers of my project to show while tracking with GPS?

I've been using/testing several versions of various GIS software and run into occasional issues. Right now, my biggest with QGIS is with GPS connection/downloading from/tracking. These are all ...
1
vote
2answers
930 views

How to project TIGER & WGS84 to Spherical Mercator?

So I've been banging my head on this for about a week now. I'm using QGIS on a Mac. I have various shapefiles in WGS84 and Census TIGER NAD83 (EPSG:4269) and I would like to give them the same ...
2
votes
3answers
315 views

How to embed metadata into a spatialite layer in QGIS?

Example usage: I have a spatialite layer which contain my fiber optic cable routes. In that layer there is a column named 'Cable types' with coded integer data: 1 for aerial cable, 2 for underground ...
1
vote
2answers
2k views

How to visualize grd files in Quantum GIS?

How to visualize grd files in the software Quantum GIS?
3
votes
1answer
2k views

How to transform shp file into raster file in Quantum GIS?

I'd like to transform a shape file into raster file in Quantum GIS... and the opposite way back also (raster to shp). Can you help me?
3
votes
3answers
2k views

Are there any geocoding plugins for QGIS that interpolate along linear features instead of querying web services?

I am curious if there are any tools for QGIS to facilitate geocoding tabular data using a local linear features layer (ie, a street map with street name and address ranges - similar to geocoding in ...
2
votes
0answers
76 views

Does qgis-server support join?

I'm having troubles getting joins work with qgis-server. I'm not sure if it's a qgis-server problem or a qgis-web-client problem (bug report). Anyone has a working project using joins?
2
votes
2answers
372 views

Graduated Symbol classification not working with a decimal range

I am classifying an .adf wind resource map which I vectorised using the Polygonise tool (which worked very well). I have classified the data using the Graduated symbol renderer using Natural Breaks ...
2
votes
2answers
286 views

Is it possible to attain a classified raster with several classes in just one QGIS raster calculator operation?

I'm using qgis' raster calculator and wanted to make a new raster (oraster) from the values of an input raster (iraster). something like: if iraster>2 then oraster=1; if iraster >4 then oraster=2; ...
1
vote
0answers
225 views

Manifold 'Link drawing to query' - can I do this in QGIS?

Manifold GIS allows the creation of dynamic drawings linked to queries. Unfortunately I do not have access to Manifold as my employer refuses to pay for it, so am currently investigating ...
2
votes
1answer
453 views

Where to activate “Vector” Menu?

I am a QGIS newbie trying to work through Lex Berman's QGIS tutorial. I'm stuck in the "join" unit, because I do not see a Vector menu on my menu bar. The screen shots show that there should be a ...
2
votes
0answers
156 views

Are there Plugin Compatibility Issues between QGIS 1.6.0 and 1.7.4?

I've been working on a QGIS plugin on Quantum GIS 1.6.0 Copiapo with Python 2.5 that calculates additional values for eachf feature of a vector layer and adds them to the .dbf. We've just upgraded to ...
2
votes
1answer
147 views

How to digitize from a map with additional detail views?

I have a map with a river that includes islands within it. Some islands have a blown up version (detail views) outside of the river showing land ownership details. I would like to make polygons ...
5
votes
2answers
3k views

How to copy features from a vector layer to another vector layer with only correspondent attributes in QGIS

I have two vector layers: A first one with all cadastral parcels of a region. This layer has several attributes, it's only the geometry and 3 of the attributes I'm intrested in. My second layer is a ...
2
votes
1answer
467 views

How to show labels depending on the zoom scale and save it forever in one project?

I have got a problem in showing labels for a polygon layer : When I select "Show labels" in the layer's properties, then I select that I want to use the scaling to show or not my labels and I ...
1
vote
2answers
541 views

How to modifiy how selection highlights are displayed? [closed]

I have got a layer of points that are showed with a litlle symbol. When I select one, a red square comes around it. The problem is that this points are inside other layers (polygons) and some of them ...
3
votes
1answer
2k views

How to display places names when using Quantum GIS and shapefiles?

I am new to the world of geo systems. What I would like to do is displaying some information on a map for given regions. I downloaded shape files from cloud made web site and load layers using ...
4
votes
4answers
3k views

How to import qgis.core to python app?

I'm new to Python. I want to create GIS app with Python using QGIS library on Window 7 64bit. The way I do: install QGIS 1.7.0 I set PYTHONPATH=D:\Program Files (x86)\Quantum GIS ...
5
votes
1answer
124 views

How to keep Table Order in Identify Results?

Is there a way to keep the default table order when using the "Identify Feature" tool. I see that you can sort the "identify results" by table column name or value. I don't want the data in this view ...
3
votes
3answers
1k views

How to extract the US from a North America Shapefile?

I have a north america shapefile, downloaded from ftp://ftp.epa.gov/wed/ecoregions/cec_na/NA_CEC_Eco_Level2.zip How can I get a new shapefile from this showing only us? Is there a way doing this in ...
3
votes
3answers
749 views

How to add a raster legend with min/max values in QGIS 1.6?

I calculated/made NDVI with landsat data using ERDAS. Results of NDVI is in black and white map but I need it in colour to present the scale for NDVI with value of pixels in Map Composition. How to ...
1
vote
1answer
658 views

Why does qgis become unresponsive when adding a .sid raster layer?

Can someone provide insight into why qgis becomes unresponsive when i try to add a raster layer? Specifically a .sid raster from NAIP imagery. I can no longer add these raster layers to projects, even ...
2
votes
1answer
461 views

Why does intersect not calculate polygon areas?

this is strange: I intersected 2 shape-files and the resulting shape does not contain the Shape_Area and Shape_Length of the intersected polygons. Instead the field Shape_Area contains the ...
2
votes
2answers
552 views

How to control line width in legend in QGIS?

I have a map in which I am defining the sizes of various features in map units. When I come to generate a pdf of the map, using the Print Composer, the map itself is fine, but when I include a legend ...
0
votes
0answers
252 views

QGIS GDAL integration of new version [duplicate]

Somewhere else on this forum ("How to access file geodatabase in Qgis?") someone asked how to access data from an Esri file geodatabase in Quantum GIS? One of the answers pointed to ...
5
votes
0answers
591 views

How to get rpy2 for QGIS on OSX?

I am a new QGIS user, have installed QGIS on a Mac running Snow Leopard OSX 10.6.8 following all the instructions. QGIS seems to work well for everything other than when I boot up I get the message ...
3
votes
2answers
3k views

How to export a raster layer for external processing?

Is there a way to export all values from a raster to for example a cvs or other textfile or dbf or xls and later import (changed) values from that file back into the raster? For vector-files this is ...
2
votes
2answers
2k views

How to exclude missing values from raster layer?

In my raster layers the value -999 means "missing". Those points completely mess up any colormap in qgis because qgis treats them as normal values and includes them in the classification. I would ...
2
votes
0answers
508 views

Trouble with Python plugins on QGIS [closed]

This question has been bugging me for a while now, and I still haven't managed to solve it, so I'm giving it another go, hopefully someone may help me out. I've been having problems loading several ...
2
votes
3answers
852 views

how to extract a rectangle corner coordinates in python script

i want to extract a rectangle corner coordinates of a shape file in python script..please suggest me a solution. Thanks in advance, Bhavya
3
votes
3answers
965 views

Is it possible to create multiple buffers using QGIS?

I'm new to QGIS and have no programming skills, is there an easy/uncomplicated way to create multiple buffers around a line feature.
0
votes
1answer
350 views

GRASS and QGIS- “ not recognized…format” but it worked before

Prologue: I used my Ubuntu file viewing GUI to move data files around and "clean house" a bit. I started a new GRASS session and tried to add NED elevation rasters which I have successfully added ...
8
votes
3answers
10k views

How to convert a vector layer to raster?

In qgis in the raster menu there is an item "convert vector to raster". This behaves strangely - I do not understand how it is supposed to work. I can select a vector file, an attribute and an ...
5
votes
5answers
3k views

How to georeference a dxf?

I have got myself a dxf which is built with units in the wrong scale. How do I upscale that in QGIS? Note it does open in QGIS, just in the wrong map units and location.
1
vote
1answer
448 views

How to create one shapefile from multiple rasters?

Ok, I have about ten maps that connect along their edges to each other linking rivers and properties. When I link them all in Inkscape I end up with a large file that won't save (and a smaller one ...
2
votes
1answer
401 views

Is it possible to automatically set CRS of Rasters from PRJ file?

I am trying to learn my colleagues to display measured data (ASCII) in maps relatively easily. I can prepare project, color and symbology style for the point layer and background map. I also found ...
1
vote
2answers
338 views

Where to choose a shapefile for appending?

I want to append several shapefiles in QGIS. The ftools 0.6.1 add-on is installed. But under Vektor>Datenmanagement-Werkzeuge>Shapedateien zu einer zusammenführen (=append shapefiles) is only the ...
6
votes
2answers
2k views

Why can't I edit KML/GML layers?

Newbie here confused by my first experience in QGIS I have a handful of lines defining a bike route. Originally they were saved in a .gml file and later translated into .kml so they could be viewed ...
0
votes
2answers
358 views

Why does only one of three elevation rasters display correctly?

I downloaded a selected sub-set of the USGS National Elevation Data (NED) using their online GUI. This download came in the form of three files. The names of the files are 61471006, 61471006_2, and ...