GRASS in the Desert? Developing FOSS tools for monitoring desertification

The use of Change Vector Analysis (CVA) combined with the Tasselled Cap tranform (TCT) is a powerful remote sensing tool to monitor forests and vegetated areas, but its application to arid and semiarid environment is not straightforward. This question is tackled through the calculation of a new set of TCT coefficients using R and GRASS-GIS for SPOT and Landsat satellites, then applied and tested in change detection analysis on a short (seasonal) and a long (decades) temporal scale. Results show that the combined procedure is an effective method to detect changes in desert environment. Furthermore, the new TCT allows the use of this combined procedure for studies in arid and semi-arid regions, eliminating the doubts on its compatibility with the area of study. Further development is the creation of a new GRASS-GIS module to performe CVA, thus enabling the simple usage of this technique, until now not available in most common software