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3

The problem has a few days ago been solved in QGIS master. I have prepared a patch for QGIS 2.10 but I hope that the QGIS developers will backport it. Since only Python changes are involved, an existing installation can now be easily fixed without having to reinstall everything.


2

As stated in your comment, the upgrade to GRASS GIS 7 helped - a lot has been invested to simplify the usage (more to come!). Be sure to consider for raster data the computational region, however, this is easily done via right mouse button in the map layer manager. Note that you can create a GRASS GIS location directly from the data set: ...


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According to the docs thinning is for line features. Remember to select "area" as the feature type in r.to.vect.


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I faced the same problem just recently. And I've found a way of getting a better path. In my case, I was trying to visualise the effect of having the Panama and Suez canals. My suggestion isn't going to help you find the exact distance, however - but it will trace a more realistic minimum cost path which should be closer in length to the real optimum. ...


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GRASS GIS provides the v.net.iso module which is equivalent to the trade area in ArcGIS. See the documentation and examples based on distance and travel time: http://grass.osgeo.org/grass70/manuals/v.net.iso.html


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There seems to be some trouble with GRASS 6/7 support as a plugin and in processing: http://lists.osgeo.org/pipermail/qgis-developer/2015-July/038601.html http://lists.osgeo.org/pipermail/qgis-user/2015-August/033174.html I guess you have to downgrade and follow the mailing lists for any progress.


1

Try r.out.gdal. First, at the layer properties, you can see the raster data type of the original raster. Afterward, at the Modules List of next image, you have the parameters used by me for exporting the raster as *.tif. At the next image you can see that the process was successfully finished. The resulting raster (it was as I expected; without the ...


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The question is essentially a dupe of http://gis.stackexchange.com/a/150497/687 In short: the upgrade development to GRASS GIS 7 is work in progress and will be shipped (to my knowledge) with QGIS 2.12.


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To install the lastest stable QGIS and GRASS 6 I use: sudo apt-get install python-software-properties sudo add-apt-repository 'deb http://qgis.org/debian trusty main' gpg --keyserver keyserver.ubuntu.com --recv DD45F6C3 gpg --export --armor DD45F6C3 | sudo apt-key add - sudo apt-get update sudo apt-get install qgis python-qgis qgis-plugin-grass grass-gui ...


1

I don't know any way of doing this without writing custom code.. this is a use case I've come across in the past, but there doesn't seem to be an easy way to do it. I'd be delighted if someone points out an easier/quicker solution! There are several good stats based plugins, but they're for vector layers. Zonal Statistics is good for finding summary stats ...


1

Yes and you can automate this process with python grass.script or bash script (bat script in Windows). I test it in my system and the individual commands are (for my line vector named route and raster dem named utah_demUTM2): v.to.rast input=route value=1 output=route_raster r.thin input=route_raster output=route_raster_thin r.mapcalc ...


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Open "QGIS Browser 2.10.1 with GRASS 6.4.4". Find the vector or raster layer in the "header window". Click on the layer and drag it over to your QGIS "Layers Box".


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I imported my raster file to PostGIS and I used this function to make vectorization of my raster. I used this query SELECT (ST_DumpAsPolygons(rast)).geom,(ST_DumpAsPolygons(rast)).val from my_raster



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