Plot of temporal data sets in GRASS GIS

One of the new modules in GRASS GIS 7.03 (RC1) is g.gui.tplot. It is part of the temporal data processing framework (TGRASS) introduced with GRASS GIS 7.0 and lets you plot the values of one or more temporal datasets for a specific point. It furthermore allows plotting data of vector dataset for a defined categories and attribute. In this post I’ll use the tool to plot changes in the annual mean temperature and annual minimum temperature of the coldest month in the last century, using the CRU climate data set. First I’ll provide a brief overview of how to import and prepare the data and finally how to plot a time series using the g.gui.tplot module. Continue reading “Plot of temporal data sets in GRASS GIS”

GRASS GIS addon to create smoothed legend image

I just uploaded a small addon for GRASS GIS, r.out.legend, with which you can quickly create a smoothed legend image for floating point raster maps (continuous values as opposed to categories).

You just select the raster layer, the dimensions and resolution required and the name of the output image. Other options are to change the font and font size and the image type (PNG, BMP, PDF and SVG).

Example of an output of the r.out.legend addon

Continue reading “GRASS GIS addon to create smoothed legend image”

Compiling the gdal-grass plugin for GRASS 7

The idea of the GDAL-GRASS plugin is to directly access GRASS raster and vector data from outside. Any GDAL enabled software (QGIS, R, …) can read and write through the plugin from the GRASS database. The different steps are explained on the grass wiki. Mostly as a note to self, I am copying those steps below (for GRASS 7), with some small changes that made this work for me. Continue reading “Compiling the gdal-grass plugin for GRASS 7”

The r.series function applied to a range of values

One of the fundamental functions in GRASS GIS is the r.series function. It makes each output cell value a function of the values assigned to the corresponding cells in the input raster map layers. I use it very often in my analyses, but I only recently ‘discovered’ this option to ignore values outside an user-defined range. Continue reading “The r.series function applied to a range of values”

Finding open data for the Netherlands

Open data is  becoming increasingly important and there are considerable advantages, such as accountability, cost and time savings for users, easier knowledge sharing and increased efficiency in public services.

The importance of open data is more and more recognized (see e.g., this blog article (in Dutch) and this and this report). However, to bank on such advantages, there is a need to increase awareness about open data and make it easy to find and use the open data.  Continue reading “Finding open data for the Netherlands”