Footslopes are areas characterized by colluvial (nutrient) redeposition from upslope. As species rich Mountain hay meadows (habitat 6520) are mesophile, nutrient-rich colluvial footslopes may be excluded from a potential range.
But how to calculate footslopes by GIS means?
There is an interesting GRASS GIS 7svn-addon:
r.geomorphon - Calculate geomorphons (terrain forms) and associated geometry using machine vision approach.
Geomorphon is a new concept of presentation and analysis of terrain forms:
- Stepinski, T., Jasiewicz, J., 2011. Geomorphons - a new approach to classification of landform, in : Eds: Hengl, T., Evans, I.S., Wilson, J.P., and Gould, M., Proceedings of Geomorphometry, 109-112.
- Jasiewicz, J., Stepinski, T., 2013. Geomorphons - a pattern recognition approach to classification and mapping of landforms. Geomorphology, vol. 182, 147-156.
g.extension extension=r.geomorphon svnurl=http://svn.osgeo.org/grass/grass-addons/grass7and do a default run of the addon
r.geomorphon --verbose dem=eudem_austria forms=mostcommongeomorph search=3 skip=0 flat=1 dist=0and a run with an increased search window
r.geomorphon dem=eudem_austria forms=mostcommongeomorph_search6 search=6 skip=0 flat=1 dist=0Calculated terrain forms (geomorphons) are:
r.category map=mostcommongeomorphA quick visual comparison shows that footslopes seem to be already excluded by the calculations mentioned in the earlier blog.
Shaded EU-DEM with potential range of habitat 6520 (yellow):
Shaded EU-DEM with potential range of habitat 6520 (yellow) and footslopes (search window =6; blue) by r.geomorphon:r.geomorphon is an interesting GIS tool for calculating/defining landforms and landform elements.