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

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4answers
672 views

How to change a CSV layer attribute value from text to number - once again?

i have read most of the related postings and answers allready ... (e.g. http://anitagraser.com/2011/03/07/how-to-specify-data-types-of-csv-columns-for-use-in-qgis/ and How to change a CSV layer ...
1
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3answers
130 views

How to add data to an attribute table?

I have a shape file (points) and would like to add points using the attribute table and not the Add Feature tool at the main screen. I went over the Qs here, but didn't find a similar problem to ...
-1
votes
1answer
2k views

QGIS v2. Convert longitude/latitude to UTM projection-Zone 51J - Southern hemisphere [duplicate]

Could somebody please let me know in QGIS version 2.0.1 How do I convert Longitude/latitude default setting to UTM projection. I am bringing in waypoints from a GPS device which is set to the above ...
0
votes
1answer
81 views

QGIS-Processing GRASS-tools don't work

When I try to use the processing grass tools like r.series I always get the following messege. I deinstalled QGis and reinstalled the program totally fresh without success.
1
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0answers
8 views

Simple solution for escaping the QGIS locked into fullscreen mode on Ubuntu 12.04 [duplicate]

" No crash in this case, but I made the mistake of toggling to fullscreen mode on my netbook running Ubuntu 12.04. It's now impossible to escape this "No Menus" view, and it seems to have disabled ...
1
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1answer
153 views

Can one batch-automate the creation of QGIS heatmaps?

I have 4k point shapefiles, from which I would like to generate heatmap TIFFs using the QGIS heatmap plugin (or a functional equivalent featuring triweigth, radius and cell size selection). Is there ...
1
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2answers
143 views

What output colour format is expected by the QGIS data defined properties widget?

I'm trying to write a python function that takes a BGSREF attribute from a BGS geology shapefile and uses it to colour up the geology polygons of a shapefile. I posted my non-code working as a part ...
0
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0answers
103 views

Turn vector layer in raster layer based on cost

Hy, I am trying to rasterize some vector layers into raster layers and I know this is possible with QGIS by using the rasterize function in the raster menu but I don't know how to do the following ...
0
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1answer
512 views

How can I change the precision in the attribute table?

I'm working with QGIS, v. 2.0.1. I opened a csv-table (from an Excel-file) and now the precision is very high but I don't need this. At the moment the values are for example 15.00000000000000, how ...
1
vote
1answer
52 views

Tick boxes for a qgis plugin written in python

in a python plugin for qgis I want the user to be able to select one or more of several options via tick boxes. I imagine it to look like e.g. Qgis 2.2 tool "Vector" -> "Data Management Tools" -> ...
0
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1answer
80 views

Best, fast and easy way to print multiple polygons?

I´m almost sure that this is to tricky to solve. Often I have multiple combined polygons that I want to print. Until now I´ve devided all the polygons by the "Split vector layer", because I need to ...
1
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1answer
82 views

GEOTIFF Binary File with Color Display Issues

I have a GEOTIFF in QGIS that shows values of 0 and 1 and I want the 0 values to have no fill so that background vector layers can show through and so I can easily overlay things in a print composer ...
2
votes
1answer
1k views

Using Affine Transformation to expand polygons in QGIS

I have a shape file, and I'd like to grow each feature by 13.7% or 14%. The program crashes every-time I try to use affine transformation. Any recommendations? I don't have a license for ARCgis. ...
0
votes
0answers
42 views

I want to reproject data from 0-360 to -180 - 180 [duplicate]

I've been downloading data from NOAA in a CRS that goes from 0-360. The rest of my data is in -180 to 180. What's the easiest way to reproject or shift the data in QGIS? It took 30 seconds in ArcMap, ...
0
votes
1answer
130 views

Create transparent background for svg marker in QGIS?

I have an image that I want to use as a SVG marker in Print Composer. I created it as a .png file in Inkscape and then saved it as .svg. But the background transparency does not come across from the ...
0
votes
2answers
1k views

How to join MySQL database to QGIS polygons

I Have an *.sql file that has no spatial information. For every record there is an id. I also have a Qgis project with polygons without any id. How can i connect the polygons with the database? I ...
1
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1answer
101 views

QGIS combine Vectorlayer and Rasterlayer to one shapefile

I have to create some Thematic Maps, especially Choropleth Maps on Matlab. Therefore i've found a shapefile which I can use, but need to draw some lines there. I've imported my shapefile as a Vector ...
2
votes
1answer
178 views

QGIS 2.2 documentation

I thought I would try to write a plugin for QGIS (some Python code that I hoped I could easily port) I started following http://www.qgisworkshop.org/html/workshop/plugins_tutorial.html but that turned ...
1
vote
1answer
230 views

pgrouting unexpected output

Thats my ways.shp file. I loaded this to PostgreSQL DB using PostGIS shape file loader. I ran pgr_anlayzeGraph() on it and found it had a lot of isolated segments. Next I ran pgr_nodeNetwork() to ...
4
votes
1answer
212 views

four color theorem for QGIS 2.0 or Leaflet?

I recently looked at some other posts relating to this topic but as far as I can tell there is currently not a working plugin or script for QGIS 2.0 to achieve a four color theorem for styling polygon ...
3
votes
3answers
1k views

Per-pixel (statistical) calculations on a raster stack using GDAL

In R, it's relatively trivial to perform per pixel calculations based on a raster stack (e.g., get std.dev for each pixel on a 12 layer GeoTIFF). Unfortunately, the speed is less than desirable when ...
0
votes
1answer
158 views

gdal's polygonize function (via qgis) is not turning monochrome rasters into readable shapefiles regardless of inversion of color scale

I've tried polygonizing this monochrome bitmap as this: and this: and either way it ends up looking like this when (zoomed in) after gdal's polygonize operation: Is there any way I can tell ...
1
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1answer
1k views

QGIS 2.2.0 install via OSGeo4W overwrote/lost qGIS ver. 2.0

Just installed ver 2.2.0 Valmiera through the OSGeo4W advanced installer for a test drive. It overwrote existing ver 2.0 in the process. Still want to have the previous to work from. How can i get ...
1
vote
1answer
328 views

how to create a map with oneway flows using FlowMapper for QGIS

my plan is to create a map that shows the top 50 (by amount of passengers) international flights departing the United States (e.g. New York -> London, Honolulu -> Tokyo...). I want to use the plugin ...
0
votes
1answer
56 views

How do I label my map with attributes?

help is always appreciated. I have a state map in QGIS 2.0 with all of the county names and some other info listed in the attributes table. I would like to have the name of the counties and one of ...
5
votes
2answers
295 views

Raster: mosaic first, or project first?

I have a thousand raster tiles in un-projected decimal degrees from which to build a seamless mosaic in a metres-based coordinate system. The final image will be about 70,000px by 50,000px. Which is ...
5
votes
2answers
734 views

Load and display a layer from SQL Server using PyQGIS

I'm having a go at using pyqgis from within the QGIS python console to load a layer from SQL Server and display it. I feel like I'm part way there but I'm having a real issue getting the layer to ...
2
votes
2answers
735 views

Conversion of Latitude/Longitude to different map projection

I have two m*n matrices coming from a WRF-ARW simulation: one exclusively with longitude values and one with only latitude values. For both matrices I know the originatin projection (lambert conic ...
1
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0answers
305 views

QGIS 2.2 saving layer as CSV with GEOMETRY=AS_WKT not working

Just upgraded to QGIS 2.2 and it looks like saving a layer as CSV doesn't support GEOMETRY=AS_WKT anymore. The new Layer Options portion of the save dialog is cool but it looks like GEOMETRY and ...
1
vote
1answer
154 views

data defined labeling with postgis layer

How to use the expression based (edit: data defined) labeling with postgis? I'm wondering, whats the best way to use expression based (edit: data defined) labels with postgis (I'm new to postgis). ...
1
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2answers
255 views

How can I add custom CRS with +proj=mercxx to QGIS 2.2.0 Valmiera?

i've builded a custom proj.4 library, tested it by command line (proj and cs2cs) and with postgres/postgis. All works fine. Now i'm trying to make the same with Qgis 2.2.0. I've replaced the original ...
2
votes
0answers
172 views

Bivariate Mapping (running a single variable regression and mapping r-squared value)

I am hoping to produce a bivariate map displaying the correlation between two variables (specifically percent SNAP participation by county against several social variables). I would like to produce ...
1
vote
2answers
583 views

QGIS Valmiera, Labels only show for part of polygons

Using 2.2.0-Valmiera on Ubuntu 13.10 I have for Croatia 21 Counties as polygons. Labels show only for 12 counties: here I see that no labels are shown for multipart features. So I checked "Show ...
2
votes
1answer
64 views

How to properly combine and export (as raster) vector lines on top of raster

I have a georeferenced TIFF with building plans on it. I then laid topo lines on top of it. it looks right in QGis. I now want to export this as an image (i.e. with the topo lines overlaid). How do I ...
3
votes
1answer
130 views

Is it possible to distinguish between points with the same coordinates?

I have several points with the same coordinates in one layer and of course they are located on top of each other. Is there a way to separate this points automatically (not manually)? I don't want to ...
4
votes
2answers
495 views

How to set the transparency for multiple layers or add a global transparancy preference?

How can I set the transparency to 27 % for all 245 layers in QGIS? The only way I know of is by right clicking on the layer name, selecting Properties, then Transparency and then moving the ...
1
vote
1answer
143 views

Display postgis data with qgis 2.2

I have a problem with some shapefile, PolygonZ type, I have imported with "shp2pgsql-gui". This is the output (note 'coord_dimension' value): mode=c, dump=1, simple=0, geography=0, index=1, ...
1
vote
1answer
2k views

Add file GDB in quantumGIS 2.2

In QGIS 2.2.0, while adding vector layer, 'ESRI FileGDB' option was missing under Source-Type, refer the attached screenshot.In this case, how can I attach a file GDB in QGIS 2.2.0?
2
votes
1answer
369 views

How to select by attributes and calculate aggregates using Modeler?

I need to know how I can select/aggregate equal attributes in a table. This is quite the same I want to do. But I want to do it with the modeler. How to group and count attribute data? The column ...
0
votes
1answer
346 views

QGIS 2.0 - can't select items in Print Composer

I am having an issue where I can create a print Layout in Print Composer, but once I have clicked away from an item (like map, legend, arrow, etc) I cannot select it again. Any pointers would be ...
1
vote
3answers
166 views

Invalid geometry message when using Difference tool

I am using the Vector \ Geoprocessing \ Difference tool to get the resulting area when taking a) current ground disturbance away from b) historic total ground disturbance to give c) what has been ...
18
votes
2answers
4k views

Does QGIS have the equivalent of ArcGIS's Layer (*.LYR) file?

Using ArcMap, it is possible to add a dataset (eg a shapefile) to the map, and configure the layer's properties (such as the symbology, table joins, switching some attributes off in the Identify ...
0
votes
1answer
514 views

How can I correct a .pgw file for a PNG image?

I have a PNG file and I need its .pgw file to be set with NAD 83 as the projection. I have created a .pgw file: 799 0 0 -799 -122.562 37.1946 However when I open the PNG in QGIS or ArcMap 10.2 it ...
2
votes
1answer
118 views

Is it possible to remove (Actions) and (Derived) from the QGIS Identify dialog?

When identifying a layer in QGIS 2.0.1 Dufour, the Identify Results dialog shows (Actions) and (Derived) keywords: Is it possible to remove these? Thanks
0
votes
1answer
32 views

How to select the identities of a layer present just in one identity of another layer

I'm a student approaching to QGIS 2.0.1-Dufour. My goal is to know how much identities of a layer are present just in one identity of another layer. I tried both with the tools "spatial query" and ...
0
votes
1answer
47 views

How can I locate additional GCPs?

I'm a new user of QGIS. I'm georeferencing a scanned image of topographic map. At least 16 GCPs were required for us to locate. However, only 12 can be located and can be identified and be defined ...
2
votes
1answer
319 views

Postgresql table won't display in QGIS 2.2

I just downloaded QGIS 2.2 to check it out and now one (just the one) of the tables from one of my PostgreSQL database won't display. It loads just fine in 2.0. The records are all there (there's ...
2
votes
2answers
363 views

Using Qt Designer to Create a Form in QGIS that can search for a specific point in a layer

I would like to ask if you can create a form in Qt Designer to create a form that can search for a point on the map using data that the user will provide such as the Name. I am currently creating a ...
1
vote
1answer
1k views

How to install OTB/Sextante plugin on QGis 2.0 (OSX)

I remember the Sextante plugin used to be available for my previous version of QGis. When I got a new computer however, I downloaded QGis again and got 2.0. Searching for "Sextante" or "OTB" yields no ...
3
votes
2answers
272 views

Merging DEMs of different grid size

I'm trying to merge two grids with different cell size. One has a cell size of 10m and the other 50m. The 10m one covers a subarea of the 50m one. I know that the most accurate one is the 10m one and ...