On Tue, 23 Jul 1996, R.A.Sanderson wrote:
Does anyone have experience of using a flatbed scanner (e.g. HP ScanJet) to
scan colour maps from paper, and convert them into GRASS raster maps
(running GRASS on SunOS). I have managed to get a simple test map,
containing only 2 colours, into GRASS, via r.in.sunrast, but it has proved
very difficult to clean up the image, to remove speckles without changing
the total areas of each scanned colour. I've tried using r.buffer and
r.neighbours, together with r.mapcalc. The main problems are associated
with text on the map resulting in a "noisy" image, and editing out these
points using d.rast.edit is too slow to be practical.
I did all that type of clean up in a good paintbrush program before
conversion and rectification. Photofinish and Photoshop are made for
that sort of thing, and on my Pentium 32MB I can edit scans close to 30
MB in size without too much hair loss.
Len Coop coopl@bcc.orst.edu