Jean-Pierre Rossi introduced a function to calculate the “Multivariate Environmental Similarity Surfaces” in R. Since then, the function has become part of the dismo package, which is a package maintained by Robert J. Hijmans and which offers a whole lot of functions for species distribution modelling.
The function calculates the MESS based on a point layer (the reference points) and a set of raster layers (the environmental data layers). It works great for smaller data sets, but you may run into trouble for very large data sets. So I needed to find a way to run this faster. And… I couldn’t. It is already a pretty neat piece of code, and I could not think of a better way of doing this in R. (I am working on For an alternative to do this in GRASS, but more about that later: see here).
The maximum-entropy (Maxent) methods is one of the most widely used approaches for species habitat modelling. It has its own dedicated software, the Maxent software (written in java and therefore cross-platform). The software is easy to use and includes fairly a complete help file and tutorial. But things get better… Continue reading →
LibreOffice is still not playing nicely with the Unity interface of Ubuntu. For a start, it does not support the global menu. You can enable this by installing the lo-menu package (available in Ubuntu software centre). This doesn’t work for me though; after installing the Window menu disappears. This means loosing access to the split and freeze functions in Calc. Continue reading →
The list of plugins for QGIS is becoming rather long, which is a testimony to how active the QGIS community is. It does make it more difficult to find and select the plug-ins for your work. And if you find one, how do you know if it is any good?
Now, thanks to Alessandro Pasotti, you can consult the list of plugins ranked according to popularity and downloads. And, if you think the plug-ins you are using are awesome, go and cast your vote for your favourite plug-in(s).
I love this website of the Biodiversity Heritage Library. Through this website, a consortium of natural history and botanical libraries have made available the legacy literature of biodiversity held in their collections. Continue reading →