[GRASS-user] Road and river extraction using GRASS

[Moritz Lennert]

On 17/10/12 19:50, António Rocha wrote:
> Greetings,
> Is there any GRASS module that can be used to river and road extraction
> from satellite images? Some feature extraction algorithm

See here for an example of a python script implementing a Sobel edge 
detection filter:
http://www.webrian.ch/2012/04/line-extraction-with-grass-gis.html

Moritz