Author Archives: pvanb

About pvanb

I am a tropical forest ecologist with a focus on spatial and temporal patterns and processes at population and ecosystem level. I am furthermore very interested in issues related to conservation and sustainable use of biodiversity and natural resources under current and future climates. I have worked in the Middle East (Syria and Lebanon) and South America (Brazil) and in Eastern Africa (Kenya).

GRASS GIS 7.0 is out!

It has taken many years of development, but finally the new stable major release GRASS GIS 7.0.0 is available. Many congratulations to the developers, they did an incredible job. This version provides numerous new functionalities, including completely new modules (e.g., the spatio-temporal database support) and massive improvements in data handling, with support for massive vector layers and speed improvements.

Check out the press release and the list of new features. But most of all, make sure you download the new version, if you have not done so already, and start enjoying a whole new experience.

GRASS GIS 7.0 RC2 ready for testing

The second release candidate of the upcoming stable GRASS GIS 7.0.0 version has been released. You can read the announcement here (including the download links) or the more detailed news about the release candidate here.

If you are still using GRASS 6.4, this long list of new features and improvements implemented in GRASS GIS 7 will give you plenty of reasons why you should try out the latest and greatest.

Online data sources: the global width database for large rivers

I came across this interesting data source, and though I might as well share it.

Description: A global database of the the width of the large rivers (GWD-LR). The river width is derived from “satellite-based water masks and flow direction maps … by applying the algorithm to the SRTM Water Body Database (WBD) and the HydroSHEDS flow direction map. Both bank-to-bank river width and effective river width excluding islands are calculated for river channels between 60S and 60N”. The results are evaluated against the existing data on the river width of the Congo and Mississippi Rivers.  Continue reading

Update of r.forestfrag addon for GRASS GIS 7.0

Riitters et al. (2000) proposed a quick approach to measure the degree of forest fragmentation that could be relatively easily implemented and which only required a map with forest and non-forest. Following their approach, Sylla consult created a shell script for GRASS GIS 6.4 to create a raster layer with six categories (non-forest, patch, transitional, edge, perforated, interior and undetermined) as a measure of forest fragmentation. See their blog post with an explanation how the script works or the above-cited article for a more in-depth description.

I adapted the script to make it work on GRASS 7.0, including some further improvements, such as the option to select the size of the moving window, the option to trim the output layer to avoid the edge effect that comes with moving-window calculations and the option to keep intermediate layers.

I have now rewritten the script as a Python addon. See here for the manual page. Continue reading

GRASS GIS 7.0.0 Release Candidate 1

The release candidate of GRASS GIS 7.0 has been released, with too many improvements and new features to summarize here. Go to http://trac.osgeo.org/grass/wiki/Release/7.0.0RC1-News and check out the details!

Kudos to the developers and for the users out there that are still using GRASS GIS 6.4… this is really a good time to switch to the latest and greatest!

Update of r.mess to work in GRASS 7

A while back I wrote a GRASS GIS addon to calculate the Multivariate Environmental Similarity index (MES; see below for a short description). The addon was written as a shell script and R script and only runs on GRASS GIS 6.

I finally got around rewriting the addon in Python. This should make it easier to install (using the g.extension function) and it does not depend on R any more. You can install the addon from the g.extension menu or you can go here. Continue reading

GRASS GIS 7.0 beta 4 released

The 4th beta release of GRASS GIS 7.0 is available for download. This is the last step before the planned release candidate (RC1), so a very good time to take it for a test run.

The most important changes in beta 4 are a major effort to standardize all parameter and flag names. This will bring a better and more consistent user experience. For more details and the download links, to to http://trac.osgeo.org/grass/wiki/Release/7.0.0beta-News