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Integrating Maxent, R and GRASS GIS
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...
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Disabling Ubuntu’s overlay-scrollbars for GRASS (or other applications)
Ubuntu has this new overlay-scrollbars for some time now. They look good I think, but unfortunately, they do not play nicely with GRASS GIS. So what if you want to keep them for most programs, but...
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A faster way to calculate MESS in R – or – a tribute to Stack overflow
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...
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LibreOffice global menubar still not working properly in Ubuntu 12.10
I upgraded to Ubuntu 12.10 Quantal Quetzal about two weeks ago. As usual, there are a number of new or improved features and changes, the arguably most controversial being the Dash’s Amazon...
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Opening MODIS tiles in QGIS
NASA offers a very convenient web-based tool to select and download the tiles you need; Reverb / ECHO. The tiles are in HDF format and use the Sinusoidal grid tiling system (proj4 definition:...
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Reading GRASS GIS vector attribute tables into R
Linking GRASS GIS and R will give you a very powerful set of geo-spatial analytical tools. The spgrass6 offers a very convenient interface between GRASS GIS and R. You can read more about this package...
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Converting an ArcMap layer file into an SLD document
Most open source GIS programs can open all most common, and quite a few obscure data format (thanks to the gdal library). What they can’t open is the ArcMap layer files (.lyr). A layer file defines...
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New GRASS GIS Web Site
The GRASS GIS web team has created a whole new website. The goal was to create a simplified structure, general update and nicer experience. And they certainly succeeded, it looks great! And navigating...
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Multivariate Environmental Similarity Surfaces (MESS) index in GRASS GIS
The Multivariate Environmental Similarity Surfaces (MESS) is an index that represents how similar a point in space is to a reference set of points, with respect to a set of predictor variables (Elith...
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Extracting lines ending with specific character using sed or grep
A quick note (to myself mostly) about how to extract lines from a text file that end with a specific set of characters. In Linux, you can very easily do this using ‘grep’ or ‘sed’. But, first a little...
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Spatialite 4.0 is out
The release of Spatialite 4.0 was just announced on the Spatialite user group. You can download it from the Spatialite website. And while you are on the website, check out the page about switching to...
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Stratified random sampling in GRASS GIS
There are various options to create a vector or raster layers with random sample points, including v.random, r.random and r.random.cells. The first two generate random points within the defined region....
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Stratified random sampling in QGIS
In my previous post I described how you can create a random stratified sampling using GRASS GIS. Unlike in GRASS GIS however, QGIS has a dedicated tool to do this. You can find it under ‘research...
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Import MODIS data in GRASS using r.in.gdal
NASA offers access to its MODIS and ASTER data sets through Reverb|Echo. The data comes in HDF format and uses the Sinusoidal grid tiling system. If your gdal is compiled with HDF4 support (use...
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Check out the new Landcover Polygon overlay function in the LecoS QGIS plugin
The author of the QGIS plugin LecoS came up with a new feature which might come in handy for some of you: a polygon overlay tool. This tool can extract raster values and save them directly to the...
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Improved r.mask in GRASS GIS 7.0
I am mostly using GRASS GIS 7.0, which is the development version. Main reason I started to use this version was the better (faster) vector handling. But there are many other new features and...
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Calculating the raster cell area of an unprojected raster layer
What if you get a raster layer with number of people per raster cell, like for example the population layer from Afripop, and you want to convert it to a population density layer? Well, obviously, you...
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New release candidate for GRASS 6.4.3 is out
The second release candidate of stable release 6.4.3 is available now. It contains a good number of improvements and especially stability fixes, see here for more details.Filed under: GRASS GIS,...
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Looking for a pdf reader with good annotations options
I read my articles on my (Android) tablet or on my computer (Ubuntu 12.10). On both, I want to be able to add notes and underline and highlight text. For Android there are various apps that allow you...
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Find Latitude and Longitude Values in Google Maps
Getting the coordinates of a location on Google maps isn’t as straight forwards as one may expect. But, as usual, if you know how, it is easy enough. And, there are actually several ways. What’s here?...
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