I just updated the r.forestfrag addon for GRASS GIS. The addon, which I described before, was developed based on an script by Sylla consult, and can be used to characterizes the degree of fragmentation following the approach proposed by Riiters et al. (2000). It identifies six categories of fragmentation, viz., interior, perforated, edge, transitional, patch, and undetermined, based on the amount of forest and its occurrence as adjacent forest pixels within a user-defined distance (i.e., the user sets the size of moving window used to compute the index). Continue reading “Update of r.forestfrag addon”
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 “Update of r.forestfrag addon for GRASS GIS 7.0”
Some time ago I came across this post from Sylla Consult about a script to calculate forest fragmentation index suggested by Riitters et al. (2000). Obviously, it can be used for any land cover type, so perhaps landscape fragmentation index would be a better name. Anyway, the script r.forestfrag.sh is available from the GRASS-addons page.
Unfortunately, it only worked with GRASS 6.4. Because I mostly work in GRASS 7.0 I adapted the script to make it work on GRASS 7.0. I also added some additional options and changes: Continue reading “Update of the r.forestfrag addon for GRASS GIS”