[GRASS-user] Using r.mapcalc to extract road network from satellite imagery

Hi all, i have been using V.clean to get a straight line of road network from my satellite imagery which i have successfully classified and converted to vector from raster. I read some articles on r.mapcalc as a possiblility for extracting a clean road network but i tried using it but did not

[GRASS-user] road extraction using grass

So far, i have been able to extra road from a satellite imagery but it has broken lines and it also captured buildings. these are the steps i followed to arrive at this stage: GRASS 6.4.0RC5 (Pittsburgh):~/Desktop g.mlist rast pitt_composite pitts.blue pitts.green pitts.red pittthin GRASS

[GRASS-user] Re: grass-user Digest, Vol 47, Issue 52

Hi all i am getting an error when i run the i.gensigset on the training map i created and the trainig map is blank after i perform vector to raster. this is what i typed and the result: GRASS 6.4.0RC5 (sis):~/Desktop i.gensigset trainingmap=traingis group=sislabgp subgroup=sislabsub

[GRASS-user] Training map error. missing classes

Hi all i am getting an error when i run the i.gensigset on the training map i created and the trainig map is blank after i perform vector to raster. this is what i typed and the result: GRASS 6.4.0RC5 (sis):~/Desktop i.gensigset trainingmap=traingis group=sislabgp subgroup=sislabsub

[GRASS-user] Extracting road network from satellite image using GRASS

Please what's the procedure or commands for extrating road network from a raster map? i think i have been going round the circle with classofocation and rectification of image. i have used this commands but i don't get any results: i.group i.composite i.class i.cluster r.digit i.maxlik i.gensigset