Chi every day has the chance to work with map data, must necessarily adapt to using different software. In recent days I've been testing some functionality of GRASS GIS software and in particular the use of raster data sources we consider that very often lack information almost always used as a simple shell background in our GIS. Instead, the raster maps contain a wealth of information, on them can be queried as to vector data as arrays of numbers. With the command "r.mapcalc" you can make any kind of transaction logic / arithmetic on the values \u200b\u200bof the cells.
Among the various tests and analysis of raster data, there is a command "r.los" which, from a 3D raster map, creates a raster map with all the cells that are visible from an observation point thus generating a map of the visibility :
Another remarkable feature is the ability to classify the images in order to obtain a map of use Soil distinguishing the colors of the pixels and divides the area into polygons
representing all the different land cover: roads, buildings, forests, rivers, etc. ...
here's an example taken from a common orthophotomaps:
you soon ....
