[GRASS-user] Road and river extraction using GRASS

GRASS GRASS user
1

Greetings,
Is there any GRASS module that can be used to river and road extraction from satellite images? Some feature extraction algorithm
Thank you
Regards,
Antonio Rocha

2

Hi,

On Wed, Oct 17, 2012 at 7:50 PM, António Rocha
<antonio.rocha@deimos.com.pt> wrote:

Greetings,
Is there any GRASS module that can be used to river and road extraction from
satellite images? Some feature extraction algorithm

you can try new (and experimental) modules from grass7 addons - i.edge
and r.houghtransform. i.edge is for detecting edges using canny edge
detection algorithm [1] and r.houghtransform uses hough transformation
[2] to detect straight lines (maybe good for roads but not usable for
rivers).
r.houghtransform can take the output of i.edge as an input.
Unfortunately there is no information in the man page yet but you can
always ask.

Anna

[1] http://en.wikipedia.org/wiki/Canny_edge_detector
[2] http://en.wikipedia.org/wiki/Hough_transform

Thank you
Regards,
Antonio Rocha
_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

3

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