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

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2
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2answers
456 views

Simplify Multigeometry polygons in QGIS

I am really new to QGIS and KML so this might be obvious but I am too ignorant to know what to do. I have some KML files I would like to use in an application but they are much more complicated than ...
1
vote
1answer
493 views

QGIS Map tools and Map canvas--QString errors

I'm trying to learn more about using QGIS Map Canvas widgets and creating custom map tools, so the information from the PyQGIS cookbook is very helpful. After trying to experiment with mywnd.py from ...
2
votes
1answer
415 views

QGIS html annotation relative paths

I find the QGIS html annotation tool is very useful for quickly accessing a combination of key data attributes and photos. I am having trouble using relative paths for images. This doesn't work: ...
3
votes
1answer
259 views

Change from polygon to multipolygon in postgres

can somebody describe please how to do the transformation from polygon to multipolygon in the postgres DB, is not possible for me to save my edited data. All data loaded just need to do some editing ...
1
vote
1answer
201 views

How to select and zoom in features from a QGIS Python Plugin

I'm very new to Python. I'm trying to find a way to select and zoom to the features from a QGIS layer. I've created a plugin and built a custom form. I have 3 values from the form which I need to ...
1
vote
0answers
294 views

Looking for cloud hosting similar to QGIS cloud

I have about 6 or 7 large clients who each require some form of personalised online mapping service. My aim is to produce a secure login required database for each client using my shapefiles and ...
1
vote
2answers
471 views

How to create a time series with a NetCDF raster from Ensembles E-OBS using GDAL, R, GRASS GIS or SAGA GIS

I downloaded a NetCDF file that contains daily precipitation values from 1-1-1950 to 30-6-2013. The raster has 23191 bands. http://eca.knmi.nl/download/ensembles/download.php My goal is to analyze ...
0
votes
1answer
75 views

QGIS 2.2 expression string builder removes brackets

in QGIS 2.0.1 is used to calculate minimum building distances (Abstandsflächen in German) with an ellipse marker with data definded properties. the expression for this is quite complex: (('Value 1' ...
0
votes
1answer
67 views

Why do field values change when exporting from QGIS?

Today I came across a very strange behavior of QGIS. Maybe someone knows what's going on? I have a table with two fields which are defined as Double, with a Length of 20 and a Precision of 0. Some ...
0
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0answers
47 views

Why can't I save a line shapefile?

I'm working with qgis v. 2.0.1. I have some data points and I just wanted to create a new shapefile with line geometry. In the new vectorlayer-window, I added some attributes (approx. 10) and klicked ...
1
vote
1answer
167 views

Reprojecting kml in NAD27, 83 or WGS84 using QGis

I have downloaded a kml file from Google containing location of shops. The coordinates in that file are in lat/long. I have other shp files containing roads and territories. I am trying to have all ...
1
vote
2answers
94 views

Highlight specific area in a box in print composer

My problem can be easily illustrated by the first picture on this site: http://bitmedia.dk/rentegning-af-kommunekort-til-faktaillustration/ I already have the overall map, but I want to make a box in ...
2
votes
2answers
111 views

How to number points along a line consecutively

I have a line and along this line I have different points which are max. 20m away from that line. Now I would like to number the points along the line, like shown in the grafic. Any suggestions how to ...
0
votes
1answer
49 views

Changing band for greyscale in plugin

I am trying to make a qgis plugin to change which band in a multiband data set (netCDF where the band represents time steps) is used for a grey scale rendering. The file works fine with manual ...
0
votes
0answers
19 views

Atlas - How to set in rows from table linked to polygonlayer?

I have polygonlayer and a textlayer. The polygons have unique ID´numbers. The textfile also have unique ID-numbers (and therefore possible to join together, yes), but it contains several rows with the ...
0
votes
1answer
55 views

how to findout semi attched or detached polygon in Qgis?

i m quite new to GIS,i've got polygon shapefiles and i want to find out the way that polygon are attached,semi attched or detached.i have area and perimeter of polygons,but i want to know length and ...
1
vote
1answer
147 views

How to Lock Grid and Scalebar in QGIS Atlas

Have just started using Valmeira and I am looking at generating an Atlas. I am using irregularly sized features as the index. The challenge I have, is when I set up the template page and scalebar ...
1
vote
1answer
333 views

QGIS 2.2.0.1 Valmiera, Windows 7 64 bit - copying out of GDALInfo-Window in QGIS not possible

When trying to copy information given out by GDALInfo with different kinds of raster data (DEM, normal georeferenced images etc.) through the interface of QGIS 2.2 by right-clicking and choosing copy ...
2
votes
2answers
1k views

How to extract X Y coordinates and RGB from pixels using python in QGIS?

I'm trying to white a Python plugin in QGIS (2.2) to get, for each pixel of a raster image, its X Y coordinates, as well as, its RGB (3 bands) values. At first I opened the raster file using: rlayer ...
3
votes
1answer
225 views

PostGIS create read only user for QGIS

I am having issues reading spatial tables in QGIS with a select-only "reader" user. I can create the reader user to access regular postgres tables like this: GRANT USAGE ON SCHEMA test TO reader; ...
0
votes
1answer
269 views

How to extract NDVI values into polygon vector map with QGIS

I have calculated the NDVI values of a satellite image using the raster calculator. Now I need to have these NDVI values extracted into the attribute table of my polygon vector file. Is there a ...
0
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0answers
30 views

How can I remove dipoles from rasterlayer in QGIS 2.2?

I work with geomagnetic survey data. When convertet into a rasterlayer, every object with a high magnetic potential (for exampel an iron-nail on the surface) is shown as very sharp anomalie called ...
0
votes
1answer
102 views

Layer relations via Python

Is it possible to, through Python, to create the relations that it's possible to create in Layers/Properties/Fields/Relations, and if so how? I first thought these were saved in the styles, but that ...
1
vote
2answers
144 views

How to save QGIS composer template with image - e.g. company logo?

I can't figure out how to save QGIS Print composer template with image. In our map compositions we always have company logo in one place. It is easy to add image (logo) to composer and place it to ...
1
vote
2answers
107 views

How to disable “Simplify geometry” via Python?

After I've loaded a layer from a table in my db I'd like to disable the 'Simplify geometry' (found in Layers/Properties/Rendering) programatically using Python. I've tried several versions of ...
2
votes
2answers
622 views

How to import a 3D DXF file into QGIS with z information as attribute value?

I have a dxf file of 3d contours. after import it does have only layer,x,y attribute and doesn't have Z attribute. how can I provide Z attribute to create a TIN file.
2
votes
3answers
1k views

QGIS 2.2 Crash dumped on Windows 8.1

After I installed QGIS 2.2 via OSGeo4W, as I click the icon of QGIS, then it shows this up, so I can't open QGIS 2.2 Here's some look like troublesome lines in my installation log, 2014/03/23 ...
4
votes
0answers
435 views

How to create multi-ring buffers automatically in QGIS? [duplicate]

I'm wondering if anyone knows of a tool or plugin for QGIS that allows for multi-ring buffers. I've found a post about doing multiple buffers one by one, but was hoping there was a way to do this all ...
0
votes
0answers
68 views

QGIS 1.8 runtime error under Windows 8.1

I tried to open qgis 1.8, and everytime I click its icon on my desktop, shows this, and then it crashed, thus I always couldn't open it. I saw an analogous question in this post, Microsoft visual ...
0
votes
1answer
245 views

Why is shapefile layer not visible on WMS layer in QGIS?

In my QGIS project I have added a WMS layer for which the CRS is WGS84 EPSG:4326. Now I want to show my shapefile layer which has the same CRS. QGIS shows the layer separately but does not show with ...
1
vote
0answers
312 views

Editing QGIS point layer: retrieve attributes of intersecting line layer

I'm creating a custom editing form using QGIS 2.0 and would like to modify the mouse event when creating a point. I've gotten a start by reading this thread: How to programatically check for a mouse ...
2
votes
2answers
758 views

How to set Eclipse and PyDev for QGIS when ArcGIS is installed?

I have got a lot problems with the configuration of Eclipse with PyDev in order to develop QGIS plugins. The situation is very weird and frustrating. I can import qgis module using Pyscripter without ...
3
votes
2answers
222 views

How to remove/disable a toolbar via python?

How do I remove or disable a toolbar e.g., Raster, programmatically using Python?
2
votes
0answers
80 views

Zonal Statistics Freezing QGIS 2.2

Running on Windows; 8gb memory, 500gb HD, i5 cpu; Raster file: 250mb I am having a problem with zonal statistics advancing past 17%. I am trying to run statistics on a crop grown in certain counties. ...
0
votes
0answers
150 views

I had an error in Gdalwarp and i don't know the reason

I was trying to warp a raster using a mask and shift it before clipping but when i exectute the command bellow in Qgis/PyQt using QProcess: gdalwarp -s_srs "+proj=merc +a=6378137 +b=6356752 ...
1
vote
1answer
272 views

How do I add a corel scale drawing

I have a plan of a building, drawn to scale in Corel Draw. The whole drawing was 'surveyed' using the principal of taking distances from of each of these 2 points to identify the location of a 3rd ...
1
vote
3answers
2k views

QGIS 2.0.1.3 (Dufour) and 2..2.0.1 (Valmiera) 64 Bit versions: uninstall not completely possible, crashes at exit

haven't tried the stackexchange page before, but since I can't find information on this problem: I can't completely uninstall QGIS, I want to do a complete, clean reinstall, but whenever I start the ...
2
votes
1answer
173 views

Update postgres/postgis point data attribute from another enclosed polygon shapefile in QGIS

I have a placename point table in postgis with 'district' column. a districts polygon shapefile with district name in 'Name' column. See the image below. I would like to update the 'district' ...
2
votes
1answer
604 views

Importing otb into Python

I have Python 2.7 (installed together with ArcGIS 10.1). Via OSGeo4W a have installed qGIS and otb application.I was able to connect qGIS and otb and it's working fine. Through OSGeo installer I ...
1
vote
2answers
395 views

How to create a symbol with no fill color in qgis?

Where can I find a simple circle to draw it around a point feature. I can change symbol fill color as well as symbol border color. But I didn't find a way to set fill color to no color.
3
votes
1answer
415 views

How to create a x-y scatterplot from attributes in QGIS 2.0?

There are a few old packages that allow the creation of x-y scatter plots from attributes in vector data (Scattergram for 1.7) http://plugins.qgis.org/plugins/scattergrammidentify/ (SPQR for very ...
0
votes
3answers
1k views

Can't compile python plugin in QGIS (Windows)

I'm just installed QGIS 2.2 and created a new plugin from Plugin Builder. When I try to compile the plugin using: C:\Program Files\QGIS Valmiera\bin>pyuic4 -o C:\Program Files\QGIS Valmiera\bin\ ...
0
votes
1answer
203 views

How to prevent QGis (MMQGIS plugin) from interpreting numbers as strings [duplicate]

I'm using the MMQGis plugin to "Join Attributes From CSV" into a shape file and am having trouble getting QGis to interpret some numbers as numbers (rather than strings which is what its doing). This ...
2
votes
2answers
141 views

Is it possible to run a spatial query in QGIS 2.0 across multiple layers using a user-specified radius from a point?

I would like to be able to click on a point on a map to select all vector features (from multiple layers) within a specified radius of the point. Can anyone point me in the direction of how to do this ...
3
votes
3answers
884 views

Convert 800 .hdf4 files to Tiff using GRASS/QGIS/SAGA/GDAL/R

I've have MODIS ndvi data (MODIS_Grid_16 days NDVI) from the iberian peninsula, from February of 2000 to August of 2012 (really big data). How do I batch convert about 800 .hdf MODIS files to .tif ? ...
0
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0answers
51 views

Delayed moving average

I want to develop a plot of delayed moving average. The code for this in MATLAB is: nr_pontos = 36; coefs_filtro = ones(1, nr_pontos)/nr_pontos; data_dma = filter(coefs_filtro, 1, data); ...
0
votes
1answer
25 views

Given two Shapefiles, how to tell which one's CRS is set correctly?

I have a polygon shapefile projected in greekgrid (GGRS87_Greek_Grid) then I open an other shapefile which is in ETRS_1989_LAEA In ARCGIS 9.3 the two shapefiles are displayed correctly. But if I do ...
1
vote
1answer
77 views

Why are some layers saved with custom CRS while others use the appropriate EPSG code?

I have a number of .shp's that I have converted from EPSG 4148 to CPNO27. Some have come out perfectly and others revert to EPSG 1000007. I have checked and the only difference between the two is the ...
1
vote
2answers
154 views

How to avoid snapping errors in QGis?

I am using QGis version 2.2.0 and I set the snapping option to the vertex, with a tolerance of 1.5 meter. When I draw a new polygon next to an old one, it seems like the vertices are automatically ...
1
vote
1answer
236 views

What do “count”, “mean”, and “sum” in QgsZonalStatistics mean?

I am working with Qgis and making some analytics of lightdata. I've used these commands: rasterfile = qgis.utils.iface.mapCanvas().currentLayer().source() vectorlayer = ...