Hi all,
I’m trying to extract a urban road network from Quickbird imagery.
The first question is: did someone already something similar? is it really possible?
Now the technical questions: I have the RGB and NIR with 2.4 m spatial resolution and PAN with 0.6 m spatial resolution.
I followed this procedure:
- i.group to make a group with the RGB imagery
- make classes by digitizing polygons to identify the probably road and no-road pixels
- i.gensingset to make the statistic and produce the signature file
- i.smap to classify
- r.mapcalc to extract the road class
First problem: with this method I can extract the roads (approximately…) but I get many pixel too which are not road. I would need to made a structural classification too. Maybe I should use r.texture but I don’t know exactly how.
Second problem: when I get finally a good classification, a simple r.thin and r.to.vect would not be enough because the pixel are not all close and precise on the lines, but are “scattered” along the line, so I don’t get a line but many little disordered lines along the road. Is there a way to get a single and straight vector line in this conditions?
regards,
tommaso