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

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QGIS Raster Calculator: Need values to be set to 0 instead of no data

I have a landcover map with different values for the landuse options e.g. 190 for commercially used areas. Now I want to extract only these areas using the Raster Calculator with the expression ...
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9 views

Tagging polygons within larger polygons (spatial join)

another QGIS newbie here. I have a number of smaller polygons which perfectly aggregate to a larger polygon. I want to "tag" the smaller polygons with the ID of the larger polygon they make up. ...
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1answer
12 views

How to batch-process attribute tables in QGIS (or GRASS)?

I'm using GRASS 6.4.3 in Linuxmint 16. I have a bash script for GRASS which I use to process almost 300 raster files. The script first imports some raster files (r.in.gdal), then does some ...
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20 views

QGIS: relative position of items in print composer

Is there any chance to make the items in print composer relative to the margins. Let's say for example the legend. I normally align it to the corner on the right bottom where the legend is 10 px away ...
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0answers
32 views

How to create a rainfall raster from rainfall contours?

I downloaded a free rainfall data from the Philippine GIS Data Clearinghouse (PhilGIS) which are vector lines. How can I extract the data points from this? I want to extract it because i will be ...
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22 views

Converting DEM data to height information in meters using QGIS?

I'm relatively new with QGIS and currently I'm working with ASTER and SRTM DEMs. The goal is to create vector heightcontours with labeling in meter. Can you tell me how I can convert the grayband ...
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18 views

How to sort a column in attribute table programmatically

Is there any way to sort ( alphabetically ) a column in the attribute table programmatically (without clicking on the column header) in QGIS ?
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25 views

Modifying properties of Attributes Table in QGIS?

In my QGIS project I'm using vector layers that require a lot of data inputting/editing. The problem is that some of the data I'm inputting varies greatly in matter of length and structure (various ...
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10 views

Creating a marker proportionally offset along a line in QGIS 2.4 when re-projecting

One of the nice new features in QGIS 2.4 is to be able to offset markers (e.g. arrow heads) along a line as part of the styling. I am trying to display a dataset of simple lines (not polylines) with ...
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8 views

r.stream.* commands do not work in qgis environment

I have been working for a while with some grass commands in QGIS environment (r.watershed, r.terraflow, r.thin, r.to.vect etc) with out any problem. I haven't been able to get any results at all from ...
3
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1answer
23 views

Wrong scale when importing dxf into QGIS

Has anyone had the problem that the scale of the shp layer converted originally from a .dxf file turns out to be wrong? (for example I draw a line of 10 meters long in AutoCAD and imported it in QGIS, ...
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25 views

from shape files to a database

I've previously converted simple shape files to WKT so that I can store them in RDMS that has spatial capabilities. I'm a new user to QGIS, which I'm using to browse a shape file. But now I have a ...
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9 views

Raster Analysis Grid (Interpolation) Crashes

Upon clicking on "Grid (Interpolation)" QGIS crashes. I running QGIS 2.2.0-Valmiera on a Mac with OS X 10.9.4 Thank you for any trouble shooting guidance
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28 views

Polygonize Missing Polygons

Polygonize is not capturing all of the pixels in an image that has been converted to 0s & 1s. The pics below show -original geotif -geotif recalculated to 0s & 1s -polygonize output As the ...
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0answers
20 views

Are there reference manual pages anywhere for QGIS built-in “buffer” and plugin “points2one”?

Perhaps I am missing some quick pop-up help mechanism, but as a relative newcomer to QGIS (having cut my teeth on ArcGIS 10.1), I am struggling to find reference manuals (i.e. explanations of all ...
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1answer
21 views

Loading GRASS gives error installing QGIS Chugiak on Windows 8.1?

I am experiencing a problem installing QGIS 2.4 Chugiak on Windows 8.1, resulting in a error loading Grass. This may be a problem only affecting certain installations, I'm not sure. I am a noob on ...
2
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1answer
45 views

data source for worldwide cross-sections of topographic and bathymetric for woodworking art project?

i am a decent r programmer and statistician, i am able to work with data sets pretty well. i am less familiar with GIS tools, but if given a shapefile i can certainly plot political borders and ...
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1answer
41 views

Accuracy issues between data in QGIS and Google Earth

Wondering if anyone can answer this question. I have a kml in Google Earth. When I import it to QGIS, and then import the Google Earth images they are in slightly different places. I used a QGIS ...
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15 views

QGIS error when add WFS

I'm running QGIS 2.4.0-Chugiak on win7 64bit and am getting the following error while trying to add a wfs layer (using the simple Add WFS layer command): The layer ...
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1answer
20 views

Couldn't load SIP module (QGIS doesn't load Python)

I recently installed QGIS 2.4, but Python does not load. I am running on a Windows 64 bit machine. I receive the error message "Couldn't load SIP module Python support will be disabled". Traceback ...
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0answers
13 views

QGIS/TileMill/Mapbox - How to downscale grid points or another solution?

Alright, I'm a web developer new to this field, I have the following issue I have built a python based tool that converts netcdf data to csv datetime|lat|long|value - it works great. Problem is the ...
2
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1answer
37 views

Qgis - Labels automatically resize to fit within the polygon

The question of my problem is simple, I want to make labels automatically reduce to fit within the polignos. Type the biggest size is 12 and goat decrease the size to be restricted to the limits of ...
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0answers
10 views

Is it possible to leave a field null when using the calendar widget in QGIS?

I'm creating and editing data with QGIS, the data is stored in a Spatialite database but I've run into this issue with shapefiles as well. I have a field I'm storing dates in and I want to use QGIS' ...
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0answers
13 views

QGIS strongly offsetted symbols for categorized layers not visible on layer list (layer panel)

I am constructing a symbology for telecom analysis, which so far is mainly point and line features. So far it is working very well except that I have to offset the symbols to be able to avoid ...
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0answers
7 views

QGIS SimpleSymbolRenderer label for Symbol in Legend

Is there an ability to set a label for the symbol (in QgsSingleSymbolRendererV2) which is showing in the legend?
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17 views

Is it possible to rotate the geographic projection in QGIS?

I'm trying to create a Qgis plugin that can rotate a raster layer in the canvas so that the north is pointing at another direction. Unlike the thread below, I'm open to defining a custom projection. ...
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0answers
21 views

Positioning and tracing polygons over an image

On QGIS 2.0 - I want to add an image (TIFF or whatever) then resize and correctly position it over a satellite image (openlayersplugin). Then, the task is to create a new shape file layer and draw ...
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2answers
57 views

Is there a way to “zoom to feature” in QGIS?

I am the GIS Director of a city public works. I have a shapefile that I created of points on each structure and address in the city. We have been working in ArcMap Desktop for 6 or 7 years and depend ...
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1answer
33 views

What is the inverse of QgsGeometry.asGeometryCollection() in qgis python?

What is the inverse operation of QgsGeometry.asGeometryCollection() as documented here: http://qgis.org/api/classQgsGeometry.html#a7cb1cbf8cfa441456067a66ad3a25a94 I'd like to do something like: ...
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0answers
28 views

QGIS 2.4.0 Chugiak “reduced” real-type numbers. Precision problem? Bug?

I have a SHP point file created from CSV with QGIS 2.4.0 Chugiak. It contains some data on noise in a certain point. When I import from CSV, it seems to be fine, but when I export to SHP and open the ...
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0answers
15 views

How to move a layer in QGIS Toc above an existing group?

If in QGIS TOC a group already exists and I add a new layer via QgsVectorLayer* lyr= mQGisIface->addVectorLayer(uri->uri(),Title, myProviderName); the new layer will be inserted within the ...
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0answers
20 views

Creating random points [on hold]

I think I am just missing something simple but I am unable to get my random points to occur within my polygon boundary area using the random points tool in QGIS 2.4.0. I end up with my points up in ...
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1answer
31 views

Interpolation of xyz data

Data has been given to us in a HUGE .xyz file, which has been split into many component CSV files. When I upload the CSV file, then create the shape file by "save as", all is fine. When I go to ...
3
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1answer
168 views

Extract one GPS fix per day from data?

I am in the fortunate position of having 2 years worth of animal movement data. With such a large amount of data I would like to extract only one fix per day to make it easier to work with. Data = 14 ...
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1answer
20 views

Set a Required Field in QGIS Edit Form

Is it possible to make a field required in a QGIS Edit Form?
2
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1answer
18 views

QGIS, CRS's and metric measurements of distance matrix and nearest neighbour

I have thousands of points on a multiple layers and I need to get the distances between each point and every other point within a layer (so i can get min, max, mean and median distances) and the ...
2
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1answer
35 views

How to add labeling to a polygon layer?

I'm trying to add labeling to a polygons vector layer called "myVectorLayer". It does not give me an error but the labeling does not appear. palyr = QgsPalLayerSettings() ...
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1answer
34 views

Join Attributes by Location: .mdb and shapefile in QGIS

I can join attributes by location in QGIS using 2 shapefiles. However, I do not know how to do the join when one of my files is in a .mdb format while the other is a shapefile.
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30 views

Rasterize shapefile using another raster's size and resultion

Rasterizing a vector (shp) I face the following problem: I want my output file (the rasterized vector) to have the same resolution and dimensions as an existing raster. If I understand the interface ...
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1answer
17 views

Not empty geometry having blank text

i'm having problem with geometry column, for some rows i have geometry with blank text, this query will describe more the problem : select geom, ST_AsGeoJSON(geom), ST_Isvalid(geom), ST_IsEmpty(geom) ...
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0answers
21 views

Some items have coordinates switched when loading PostGIS layers in QGIS

I am having problem with strange coordinates switching when loading PostGIS layers in QGIS. First, I thought, that problem may be cause by the use of GROUP_BY feature in layer query, but later the ...
3
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2answers
61 views

Incorrect display of national characters from Spatialite in QGIS, Windows

I used this tutorial by Underdark (thanks much :-) ) to convert my area of interest from OSM file (whole Czech Republic downloaded from Geofabrik.de server). Used OSGEO4W shell (saying "GDAL 1.11.0, ...
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0answers
24 views

GISBASE not set [closed]

Hi am VERY new to all this. On Windows 7 and downloaded QGIS 2.4, I'm trying to follow a tutorial on how to manipulate Lidar data and have got to the "create new mapset" but cannot finish because says ...
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2answers
53 views

Relationship of QGIS to its sister programs?

I'v e been using QGIS 2.4 for a number of months now and we are using it a bit at work. I noted that when I did the initial install a number of new icons appeared on my desktop namely MSys QGIS ...
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0answers
22 views

Lining up three Layers that use same Coordinate Reference System (CRS) in QGIS?

How do you make all borders of a layer equal? they should be equal but i don't know how, mCRS layer is all in philippine zone 5(EPSG:3125), with the same formula/equation, I'm new to QGIS and I'm ...
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1answer
29 views

Merged Layers turned into square shape cause by single layers in QGIS?

What I did is merged the 30 layers of the map (Isabela Map Province - Philippines) and below is what happened. How do i remove the inside map of the border? I'm new to QGIS and I'm using QGIS 2.4 ...
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1answer
30 views

Can FileGDB SDK be made to support custom coordinate systems?

In May 2012, a question was asked about File Geodatabase (*.gdb) support in QGIS? In the comments there, it was pointed out by @MattWilkie that the FileGDB SDK does not support custom coordinate ...
3
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1answer
32 views

QGIS: Need to remove unwanted white bands when raster layer are overlapping

In my project when raster layers are overlapping a white band appears the edge of the top layer. How can I remove it and obtain a seamless overlapping of the raster ? (I have try to built a vrt with ...
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0answers
29 views

PyQGIS: Editable Combobox for Value Map widget isses

I am having issues with an editable combo box in QGIS 2.4. The edit widget is set to Value Map with an uploaded CSV. However, if a new values (not included in the key value pair list) is added, the ...
1
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1answer
39 views

Creating New Layer After Sorting Attribute Table using QGIS?

I have been self-teaching myself some open source GIS. I downloaded QGIS and have been following this four part tutorial - ...