QGIS live layer effects is propelling QGIS to the next level in the cartographic realm

This new feature created by Nyall Dawson and funded through crowd funding really sets new limits in terms of what is possible in terms of cartography. Check out Nyall’s post Introducing QGIS live layer effects! for a walk through of the new possibilities that this features brings to QGIS. It will be available in version 2.10, or if you can’t wait you download a QGIS development snapshot from the QGIS website to help in testing.

Sampling raster values at point locations in QGIS – an update

In a by now fairly old post I described how to sample raster values at point location in QGIS. The method I described used the ‘Point Sampling Tool’ addon. However, the function creates a new point layer, which only contains the values extracted from the raster layer. None of the fields in the original point layer is copied to the new one. It is possible to join the attribute table of the new vector point layer with the original attribute table afterwards using a spatial join as explained in that post. However, this will not work if your point data includes points with exactly the same coordinates.

Since I wrote that post, QGIS has come a long way. Continue reading Sampling raster values at point locations in QGIS – an update

Using GDAL from within QGIS: trouble shooting

Some notes to self about steps I had to take to make GDAL work from within QGIS. Both where compiled from source and run without problems. However, there are still a few issues with running gdal from the QGIS processing toolbox. This may have to do with the fact that I installed both in a non-default location (in the /usr/local/ folder), but in any case, the steps below solved the problem for me. Continue reading Using GDAL from within QGIS: trouble shooting

Rescale your raster data layer

Sometimes you want to rescale a raster layer, e.g., to reduce the number of categories, or to create a common scale for different raster layers. Very basic of course, so you can expect to find an appropriate function in any self-respecting GIS software. Just be aware that different terms are being used for the same thing, e.g., scale in gdal, rescale in GRASS and normalize in SAGA GIS. Below a few ways to do this using my favourite GIS programs: GRASS GIS, QGIS, SAGA GIS or gdal. Continue reading Rescale your raster data layer