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).

r_out_legend_4
Example of an output of the r.out.legend addon

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

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”

GRASS GIS 7.0.2 released

For those who haven’t seen it yet, GRASS GIS 7.0.2 has been released! See here for the announcement and here for a detailed overview of all the changes (over 190 of stability fixes and improvements since GRASS GIS 7.01).

For those still using GRASS GIS 6.4, GRASS GIS 7 offers a strongly improved interface, a considerable increases in speed and efficiency, support for huge files, and a long list of new modules to analyse raster and vector data, including a full temporal framework. Also important, as a stable release series, 7.0.x enjoys long-term support.

As usual, a great thanks to the developers!

Importing GLCF MODIS woody plant cover

The data set

The Global Land Cover Facility offers, amongst many other data sets, the MODIS Vegetation Continuous Fields data set for download. These are layers that contain proportional estimates for vegetative cover types (woody vegetation, herbaceous vegetation, and bare ground). As such they are very suitable depict areas of heterogeneous land cover.

Their MODIS products differ from DAAC editions by coming in GeoTIFF format, geographic coordinates, WGS84 datum, and a tiling system designed to fit well with Landsat imagery. Currently the collection 5 is available, which contains proportional estimates for woody cover vegetation for the years 2000 to 2010. It can be downloaded as tiles (195 in total) via a ftp server.

Below I’ll provide an example Continue reading “Importing GLCF MODIS woody plant cover”

Computing MESS in R and GRASS – a speed comparison

The Multivariate Environmental Similarity Surfaces (MESS) is an index that represents how similar a point is to a reference set of points, with respect to a set of predictor variables (Elith et al (2010). The function was first implemented as part of the Maxent software package, but is now also available in R and GRASS. Below, I will compare how fast the different implementations are. Continue reading “Computing MESS in R and GRASS – a speed comparison”