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

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22 views

How can I configure composer to update all the elements when the project is opened?

I have designed standard layout to display a map, multiple tables, images, etc. Every time I open this project I have to update/refresh all the elements in the composer even if the layers have the ...
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0answers
36 views

QGIS 2.0 Catchment areas by using a 1 hour walking time

i would like to have catchment areas around my points which show the area of an one hour walk. I looked around and found information about using the hiking funktion for calculating a distance with the ...
2
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0answers
28 views

What are my options to handle Raster Clipper ERROR 6: ADRG driver doesn't support 4 bands?

I have a tif file which contains 4 bands (RGB + alpha). The clipper does not work and gave me the message below; ERROR 6: ADRG driver doesn't support 4 bands. Must be 3 (rgb) bands. Any patch file ...
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1answer
29 views

WMS layer in a QGIS 2.4 stand alone Python script

What is the best way to add a WMS layer on a map, in a stand-alone python script with QGIS 2.4? The methodology explained at the bottom of the official QGIS documentation page seems to be outdated and ...
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0answers
25 views

QGIS 2.4 Clip function in Raster layer Style Single band pseudocolour not working?

I've been using QGIS for a while and recently upgraded to 2.4, but now find that displaying raster layers is difficult. In particular, the clip function (tick box bottom left of "Style">"Singleband ...
3
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1answer
38 views

Export Raster Attribute Table using Open Source software

I've got 120 or so geotiff files that I'd like to build and export the raster attribute table to something a little more friendly (e.g. csv). I'm curious if there is an open source way to do this. ...
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0answers
16 views

Trouble with reading Leaf area index (LAI) Modis on QGIS

I am having trouble reading my Modis LAI data on QGIS. I imported my Modis hdf files and I used the QGIS raster calculator to apply the scale factor and all I get is a blank gray tile. My goal is to ...
4
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1answer
43 views

Loading same layers every time

I recently started using Qgis python console for Qgis development. My first task is to load the layer and print its attributes.I firstly load a point layer using code mylr = ...
3
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1answer
44 views

Zonal Statistics Tool on raster

I am working on a one-band raster with pixel values from 1 to 7, each representing a land-use class. I also have a grid of polygons and what I need is to obtain the percentage of each class in each ...
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0answers
13 views

PyQGIS: Coordinates to TextBrowser

I'm doing tutorial: http://www.qgisworkshop.org/html/workshop/plugins_tutorial.html#tie-qgspoint-output-to-the-gui Right now I at the "Tie QgsPoint Output to the GUI". I did everything similar to ...
2
votes
1answer
30 views

r.recode rules file issue

I have a raster that I want to reclassify and I'm using GRASS r.recode from within QGIS v.2.4.0. The rules file I am using has this content: 0:149:1 150:229:2 230:379:3 380:459:4 460:*:5 The raster ...
11
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1answer
112 views

Identify points in a shapefile that have no other point within x km with QGIS

This is probably a naive question but I am struggling as a new user to QGIS. I have a very large shapefile (275,000 points, but can break this into about 10 subregions if necessary for faster ...
2
votes
1answer
38 views

Plotting NAD83 zone 8 points atop OSM or Fusion Tables

A geologist has given me a bunch of points to plot on a map I'm doing in WGS84. Her points are in NAD83, and she says they're in "zone 8." Here is one of the points. 440244 7599457 She says the ...
4
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1answer
35 views

How do I consider entity alignment against slope direction?

I am a newbie to QGIS and don't know if the following is possible so would be grateful of any thoughts. I have a hill, most of which is given over to rectangular pasture fields. I hypothesize that ...
2
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0answers
27 views

Is it possible to sync multiple radio buttons on a QGIS 2.0 custom feature form?

Is it possible to sync multiple radio buttons on a QGIS 2.0 custom feature form to one attribute? For example i have three choices (owner, renter, and other) and choosing the radio button would fill ...
1
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1answer
42 views

how to open shp file which created by using python-ogr in qgis?

I have done following steps, so how I open that created shp file in Qgis driver=ogr.GetDriverByName('ESRI Shapefile') out=driver.CreateDataSource('pts.shp') ...
2
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1answer
33 views

How to define QgsVectorLayer by QDomNode?

I am using QGIS 2.4, Python 2.7.5, win 8.1. I am trying to read layers from QGIS project. When I try define QgsVectorLayer using QDomNode and readXML function, following error appears: ...
2
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0answers
33 views

Changing grid orientation of a raster

I'm trying to load some XYZ data into a program called OpendTect. However, the orientation of the existing data is different from the grid orientation of the XYZ file. this makes it imposible to load ...
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3answers
100 views

How to export streets in a certain area from one shapefile to a new shapefile?

I have a shapefile with the roads from Europe and I want to export in a new shapefile only the roads from Greece. I tried to delete the other roads but there are too many and I have no attribute to ...
1
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1answer
58 views

Suitability Analysis using QGIS? [closed]

I want to do an overlay analysis to find most suitable locations to live in an area. My criteria are road network, water lines, hospital locations, and schools. My steps are: Convert all layers to ...
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0answers
40 views

Is QGIS Server Properly Installed?

I just installed qgis server using the instructions provided here. I am pretty sure that I have installed QGIS properly, but I am not sure. I am using Windows 7, and XAMPP. I typed the following into ...
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1answer
21 views

Flow mapper not working

Hi I am trying to run the test files for flow mapper plugin in QGIS but I run into an error message.
4
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2answers
98 views

Split lines at intersection points

I've got some linestrings covering a road network, and need to split them at the crossroads. Does anybody have any idea on how to do it? I'm using QGIS 2.4, with a Postgis 2.1.3.
2
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1answer
40 views

Compiling custom plugins for QGIS on Windows

I've made my first plugin using plugin builder and I want to compile it. I read that I need two commands to do it under windows: pyuic4 and pyrcc4. But when I use any of these commands I get this: ...
2
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1answer
44 views

QGIS reference system problem

I'm working with Quantum GIS 2.4 and I would like to overlap a DTM (.asc) and a shapefile. The shapefile is a copy from the another, to make some trials, who had WGS84 as original CRS; I saved it by ...
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0answers
35 views

How to change color ramp in graduated classification with standard deviation using pyqgis

I'm using graduated clasiffication with standard deviation to style my shapefile (see code below). But I need to use different color ramp for classes below mean (-1std, -2std etc.).I'm thinking of ...
3
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2answers
91 views

Create grid where points is centroid? QGIS

I want a grid around my points(100 x 100 m), where points are center. Creating a grid from Vector -->Researh Tools--> Vector Grid creates grid, but not centered around my points How do I do this? ...
3
votes
3answers
98 views

Is there a union function for multiple layers comparable to ArcGIS in open source GIS like QGIS?

I need a union function for a lot of polygon layers (protected areas of all kind, nature, water etc.) comparable to the union function in ArcGIS. I have only the desktop version from ArcGIS and so it ...
1
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1answer
28 views

Speeding up length calculation in QGIS 2.0 Python plugin

In a qgis 2.0 plugin for windows, I calculate length and update a field with the values. It works, but takes a lot of time. Execution for this part only takes about ten minutes. Can anyone suggest ...
2
votes
1answer
32 views

Why is too long connecting to Oracle Spatial database from QGIS client?

I am having trouble connecting to an Oracle Spatial data with QGIS client. I use QGIS Version 2.2 (Valmiera) to connect to a database schema in Oracle Spatial. I asked our DBA access to our database ...
2
votes
2answers
69 views

How to fix unreachable nodes in QGIS GRASS network?

I have created a network with the GRASS module v.net. But when I try to create the travelling salesman path with v.net.salesman, I get: Destination node 9383 is unreachable from node 9398 If I ...
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0answers
15 views

Print Custom Feature Form using PyQGIS

I recently asked a question and accepted the answer, as it was a good guide on accessing the print composer using python. However, I am still looking for a way to print the custom feature form. Does ...
3
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1answer
31 views

Superimpose OTB application via Sextante cannot load parameter

I am trying to perform a pansharpening using OTB via sextante. According to the cookbook I first need to superimpose the Pan and XPS images: http://www.orfeo-toolbox.org/CookBook/CookBooksu36.html ...
4
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1answer
57 views

Question about ArcGIS vs. QGIS for kernel density estimations

It appears from the QGIS documentation that the Heatmap Plugin can generate a kernel density surface from a point map and make use of the attributes of the original points to influence this surface ...
2
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0answers
50 views

Why do comparisons in QGIS 2.4.0 Raster Calculator return -3.40282e+38 aka no_data?

I tried to use comparisons as conditional statements in QGIS 2.4.0 raster calculator. My statement is: (a < 230) * 230 + (a >= 230) * a The expected result is raster a with all values lower ...
3
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1answer
119 views

QGIS 2.4.0 Chugiak How to remove topographic effects like shadows from landsat image

I am using QGIS 2.4.0 Chugiak on my windows 8.1, for classification of landsat 5-7 image that contains hilly mountains with dense forest and 60% area are plains. I am classifying through ...
2
votes
0answers
65 views

How to extract polygons from a road network?

I need to extract faces (or polygons) from my road network and calculate their areas. I mainly use Arcpy packages but even if you know it in QGIS APIs, I'd appreciate if you'd share it with me. If it ...
1
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1answer
42 views

qgis-web-client stuck on “Loading map” on some maps

Some maps work for me to load, while some of them never do. They do load the layer names, but nothing more. The javascript console in Chrome returns this: Uncaught TypeError: Cannot read property ...
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0answers
16 views

QGIS WMS Server Search List of Results

In the "Add WMS" dialog on tab "Search for Server" you can put in some keywords and get a list of WMS matching this topic. My Question is: How could a WMS becomes a member of this resultlist?
2
votes
1answer
50 views

Positons from GPS lanes inside a polygon

i have a lot of lanes like the orange lanes at the below picture (latitude and longitude values). Now i need all values from each lane inside the red polygon. What is the easiest way to realize ...
1
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0answers
54 views

Making air pollution model in QGIS [closed]

Im writting bachelor thesis about air pollution from point source and i want, to put it to GIS. But i dont know really how ... Im working with Gaussian plume model, so I have pollution concetration ...
1
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0answers
18 views

How to merge elevation from a raster image onto a shape road network with QGIS? [duplicate]

I have a shape file with Stockholms road network and a raster image with elevation data from the same area. Is there any way to merge the two somehow, either by adding the slope direction as ...
2
votes
1answer
45 views

How to merge shapefiles of two countries with QGIS [duplicate]

I want to merge the shapefile of Nigeria and Cameroon admin level 1. I downloaded the files from gadm but I cannot merge the files with QGIS or find a shapefile of Africa having countries at states ...
0
votes
0answers
22 views

export qgis point symbols per feature

I am currently trying to export the drawn symbol in a QGIS map for a webmap. The current approach is to extract the properties: if i.rendererV2().dump()[0:6] == 'SINGLE' and i.geometryType() == 0: ...
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0answers
26 views

How to calculate fastest bicycle routes in Stockholm with QGIS?

Hello StackExchangers, I would really appreciate if expert users could point out a few directions for me, this is what I wanna do: Access an online map from my iPhone that gives me the possibility ...
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1answer
36 views

Difference between ETRS89 / ETRS-TM32 and ETRS89 / UTM zone 32N

In QGIS I can choose among other things between "ETRS89 / ETRS-TM32" and "ETRS89 / UTM zone 32N". In my test project both projections displayed the layers at the very same place. So, where is the ...
4
votes
2answers
53 views

How to achieve “Flat-End” line buffers in QGIS?

I need to buffer a series of lines by 40m, however I only want the buffer to come off the sides and not off either end of the line. I know in ArcGIS there is a "flat-ends" tickbox that achieves ...
3
votes
1answer
64 views

Trouble calculating areas in QGIS using field calculator

I am testing various projections to calculate areas using ICES statistical shapefiles and the QGIS field calculator. I am using ICES areas downloadable from the following link: ...
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0answers
36 views

Does qgis support postgresql range types?

I added a postgis layer with date range column in Qgis but that field is not listed in Qgis.
3
votes
1answer
66 views

How to perform raster Overlay Analysis using QGIS?

I tried to do a raster Weighted Overlay Suitability Analysis to find the best location for home lands using QGIS. Used layers are: School location (point) Crime locations (point) Road (line) Water ...