Scanning maps into GRASS

[Leonard Coop]

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 at bcc.orst.edu