A (not so) short overview of the Geographic Information System GRASS LG #156: "The aim of this article is to introduce the GRASS GIS software and to show its basic usage. As with all GIS software, it is quite complex: there is a huge number of features and controls, and non-trivial theoretical information is required even for basic use. Nevertheless, we think that the quick introduction presented here could be of some help for neophyte users who want to master a GIS program."