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

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756 views

Add x y data from existing attribute table

In Quantum GIS, I already imported an excel or dbf table. Now I need to tell Quantum GIS which columns are Latitude and Longitude. How do I do that? I know there is Add Delimited Text Layer which ...
1
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0answers
306 views

Install shapely for QGIS on Mac

I know there are a number of similar questions, but none of them have answers that allow me to use shapely in QGIS. In particular I am trying to install the Contour plugin, but this fails with the ...
2
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0answers
69 views

How to run an external program on “identify” on a WMS layer?

I have a QuantumGIS project with several WMS layers. When I select one of these, the identify-function shows a windows with more information on the feature I clicked. It gets this data from the ...
2
votes
2answers
2k views

How to open an ArcGIS Desktop .lpk file using QGIS on a Mac?

I downloaded an LPK file from the ESRI site that contains USPS defined zip codes. Because I'm working with QGIS on a Mac, I converted the file to a .zip. There's a .lyr file that opened up in the zip, ...
1
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1answer
288 views

What do I need to do to add a new QGIS project to qgis-web-client?

for weeks I'm trying to get QGIS Server with qgis-web-client to work but I'm totally stuck. System is Debian Squeeze. In principle, I get QGIS Server and the qgis-web-client up and running: it's ...
0
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1answer
134 views

qgis field calculator - changing datatype

I have seen a solution that I don't get to work - I need to change data type from string to integer and I did what is shown i the image below Can someone point out what I do wrong? thx Jan
3
votes
0answers
202 views

Multiple text formats in a qgis label

Is there any way to have multiple text formats in a single qgis label? I am making a map that shows mountain summits. Many of these summits have more than one name and I would like to show each name ...
1
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2answers
180 views

How to modify the results of a geological dataset from vertical to horizontal?

I have a 3-D point shapefile of a geological fault dataset consisting of x,y, and z columns. I need to create a raster dataset from this point dataset. I have been trying to do this in ArcGIS; ...
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2answers
498 views

QGIS 1.8 python refresh maps

i have developed this plugin .. all works fine but the map wont get refreshed . here is code vectorCount =0 mpointCount=0 mlineCount=0 mpolygonCount=0 mrasterCount=0 mlegnd = ...
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2answers
299 views

Where to find the variables of QgsPolygon and QgsPolyline?

now I want to use QgsPolygon (and Qgspolyline,too) class in python I have a example by using QgsPoint but I don't know how to use in QgsPolygon following is my Qgspoint example feature = ...
3
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0answers
320 views

When will QGIS version 2 be available? [closed]

Just wondering, how close is the public release of version 2? I do realise that I can download 1.9, but was wondering about the public version.
2
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1answer
89 views

How to split complex lines?

I want to edit some complex polylines, which I imported from my GPS. These polylines have many vertices and are selfintersecting many times. When I try to split these lines using the 'Split ...
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3answers
1k views

Saving of multipolygon shape file into a individual polygon shape files [closed]

How to seperate a multi polygon shape file into individual polygons(as seperate shape files)? i had huge data... I know the traditional process like export data... Please help me.. Thanks in Advance
1
vote
1answer
290 views

How to create a 4 band image from an RGB and a grey scale image?

I have an RGB image and a Gray scale image. I would like to merge them in a 4 bands image. How can I do that? Is there a simple way to do it from QGIS or I have to modify the image before to load them ...
1
vote
2answers
1k views

How to fix OpenLayers plugin for QGIS Master?

I can't get the OpenLayers plugin to work in QGIS Master (1.9), I loaded the repository successfully, but the plugin doesn't come up as an option anywhere. I'm new to this, but have tried to make ...
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0answers
125 views

QGIS 1.9 problem with setGrayBandName on the QgsRasterLayer

I have installed the developer version of QGIS on my computer in order to do some work with a multiband raster file. The file consists of 30 bands of information, and I need to step through it with a ...
0
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1answer
239 views

Why postgis st_overlaps reports Qgis' “avoid intersections” generated polygon as overlapping with others?

I am implementing a postgis trigger on polygon layer to check and reject newly created polygon if it overlaps others. The problem shows when I digitize new polygons adjacent to others in Quantum GIS ...
0
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1answer
161 views

How to symbolize features in QGIS?

Why is a shapefile shown as coloured independent features in ArcGIS shown in a single colour in Quantum GIS? What can I do to display this layer (wwf ecoregions) with the different ecoregions ...
1
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0answers
55 views

Why are the Raster z-value changed when reprojecting?

i have raster data with height values (z). when i try to reproject/warp the raster to gauss kruger 3, the z-values are changing (several meters). (the data is already gk3, but i have to reproject ...
4
votes
1answer
386 views

How can I create a new layer from the currrent selection?

Is it possible to create a duplicate layer, only displaying the selection from the layer you are duplicating in QuantumGIS? Simular to ArcGIS -> Create Layer from Selected Features. I looked at "How ...
1
vote
2answers
59 views

Discontinuous elevation contours at boundary of CanVec datasets

I am using Quantum GIS and I am working with the elevation contours from two adjacent CanVec datasets. The problem is that many of the contours' endpoints at the shared boundary do not coincide with ...
1
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1answer
253 views

Why doesn't the Kernel Density Estimate function appear in AniMove plugin?

can anyone tell me why the Kernel Density Estimate function does not appear under my AniMove plugin in QGIS? I can only perform the MCP. I run Windows OS.
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0answers
22 views

Shapefile is not a valid or recognised data source. [duplicate]

I have some shapefiles that I have been using before, some months back, but now I try to load them into QGIS but I get the message: districts.shp is not a valid or recognised data source. I realise ...
4
votes
0answers
1k views

How to open a ESRI geodatabase in QGIS (Ubuntu)?

So far I have found instructions on stack exchange but they are for windows. And so far the information I have found is for windows. I currently have Ubuntu 13.04 Raring tail. I am using qgis 1.8. I ...
10
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1answer
2k views

How to create desire lines in QGIS?

How can I show the flow coming from an Origin-Destination matrix as desire lines? I need a result like the one in the picture below. I need to scale them proportionally to its value (coming from a ...
4
votes
1answer
400 views

Experiencing transformation anomalies when performing a Save As to convert coordinates between NAD83-Z14 and NAD27-Z13

Good morning all: I have recently discovered QGIS and have been hoping to find a solution for converting bacthes of xy coordinates between two projection systems for our mapping system. I have known ...
1
vote
1answer
250 views

JSON URL won't open in QGIS

When attempting to display the national chargepoint registry from the following URL: http://chargepoints.dft.gov.uk/api/retrieve/registry/format/json The following error returns: ...
1
vote
1answer
206 views

QGIS offset dash line style - dash spacing does not vary with rotation

I'd like to make a USGS-style dirt road marker but with smaller dashes and bigger spacings (i.e. less duty cycle) to indicate lower quality road. First attempt = two simple lines, custom dashes of ...
1
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1answer
242 views

Combine shape in folder for on/off

Is it possible to organize some shapes into folders to turn on/off all the shape togheter? Is it useful for the shape that you can punt at the top/bottom of a project.
4
votes
1answer
919 views

How to make the thickness of traffic volume flow symbology proportional to traffic counts?

I can scale the bandwidth proportionally to the traffic volumes; however, I cannot show the directionality of the movements. Volumes for directional moves are stored in two different columns of a ...
3
votes
1answer
217 views

How to represent Typhoon(s) wind speed using Quantum GIS / PostGIS?

I am not completly new to GIS (was taught ArcGIS at Uni) but I would still consider myself (especially compared to all these experts here) a newbie in QGIS or PostGIS. I want to display the ...
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votes
1answer
64 views

How to search for text in QGIS?

Does QGIS have any search capability, for example to find text within cadastral polygons? Quantum gis posee algun buscador , por ejemplo para identificar textos en poligonos de catastro ?
2
votes
1answer
271 views

ImportError: No module named qgis.core

I am on Ubuntu 13.04. I get the following error message - Traceback (most recent call last): File "analyse.py", line 1, in <module> from log import shelve File ...
2
votes
2answers
1k views

Setting “R Folder” Path in QGIS Sextante

I have installed R via the R-Project website. I have QGIS installed via OSGEO4W (currently 1.9.0 Master), and have Sextante plugin installed and working with GRASS and SAGA providers. I am now trying ...
2
votes
1answer
354 views

How to perform a cascaded combine from python script in QGIS?

I'm working with a large dataset, and I need to be able to combine up to 400,000 polygons. I have been using the QgsGeometry::combine(QgsGeometry* geometry) function and simply looping over all ...
2
votes
1answer
112 views

How can I confirm the existence of pyramids in QGis?

I have created pyramid layers for my ASTER satellite images (.img) using Gdal Tools "Build Overviews" (Pyramids). The dialog said "Processing completed". I don't have the impression that zooming in or ...
2
votes
1answer
155 views

Lack of Options in Gdal Tool “Build Overviews” QGis

I am using QGis 1.8 and I want to build overviews (pyramids) for satellite imagery using the Gdal Tool. I would like to use the resampling method "cubic convolution", but the option doesn't exist ...
0
votes
2answers
396 views

How to handle an “Input CRS error” when clipping?

I'm trying to clip a soil use shapefile, with a polygon I've created this morning. The clipping function works, but the clipped polygon doesn't have features (the table of contents is empty). QGIS ...
2
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2answers
260 views

How to rotate North oriented Map [duplicate]

I want to rotate my North oriented point shapefile to 45%,is there any way to rotate it QGIS or Mapinfo? Thanks, RKM
3
votes
1answer
194 views

How to create a line layer which connects a point layer to a line layer?

In the map shown below, I have manually created the dummy lines (in green). Using python, and without using PostGIS or sextante, I would like to automate the creation of these dummy links between a ...
2
votes
1answer
270 views

Are there Open Source alternatives to ArcGIS Aggregate and Extract Value to Points?

I am looking for some kind of Open source GIS library which can perform spatial analytic functions same as ArcGIS. My use case is : I am processing GeoTIFF file provided by USGS and performing ...
2
votes
0answers
90 views

Rounding error in qgis point sampling tool

I'm not sure if this is a bug or of it is due to the implementation. I am using a raster that has values greater than 1,000,000 and Qgis displays these numbers in a scientific notation. For instance, ...
5
votes
1answer
79 views

Permanent Histogram Stretch with QGIS or FWTools

Is there a way to permanently stretch a histogram of a raster within QGIS or gdal? I would like to stretch a satellite image with a Standard Deviation 2.5 stretch. I would prefer to use QGIS or ...
0
votes
2answers
523 views

Why can't I select any of the tools under “edit”?

Why can't I click any of the tools under "Edit?" I want to merge selected shapefile layers together, but all of the tools under "edit" are greyed out.
2
votes
0answers
898 views

QGIS: After performing a table join, all the fields are “NULL”

Within QGIS, I joined .dbf table containing population data to a shapefile of Census tracts. The join field is called GISJOIN in both the target table and the shapefile's table, and this attribute ...
2
votes
1answer
2k views

Instructions for installing Sextante plugin

As a follow-up to the question I recently asked on PyQGIS, can someone please point me to a document, webpage or thread that provides me with step-by-step instructions as to how to install an external ...
3
votes
2answers
491 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 ...
0
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0answers
516 views

How to move/edit labels? [duplicate]

I need to move/edit few labels in a job. How can I work on it? I am using QGIS 1.7.4 and the label option in the toolbar (not the layer options)
1
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0answers
232 views

QGIS Points to Path Plugin Date/time error [closed]

I would like to use the Points to Paths plugin to plot the tracks of collared animals, exactly as specified on this page http://spatialgalaxy.net/2011/12/30/qgis-plugin-of-the-week-points-to-paths/ ...
1
vote
2answers
242 views

How to re-calculate area, perim, p2a,width and length in QGIS?

I cut a part out of one feature and added it to another feature in a polygon shapefile. My problem now is that both features has the same values in the area-, perim-, p2a-, width- and length-columns? ...