Hello Lurker,
Tks fo the tips...I used IDL (ENVI) and have used the 'canny' function...but I have not yet what I am looking for. Endeed, I have seen that PCI geomatics can draw edges (maybe vectorial) detecting the lineaments whereas ENVI, with the help of filters just change the image (but I would like to have the vectorial elements correcponding to the edges (fractures is what I am looking for)). Does ER MAPPER can do this ? Or any software suggestion to automatically extract fractures and have the vectorial file corresponding (shapefile) ?
Tkx,