using grass for GEOLOGY

[Don L. Sawatzky]

    My advice is NEVER digitize a complex geologic map by hand.  The
result is too inaccurate and otherwise unsatisfactory.  The best procedure is
to prepare stable copy for scanning by removing all artifacts not wanted in
the product.  Then, have it scanned.  Editing scanned copy is much easier.
If you have the funds available, contract for scanning and editing, or only
for scanning and do the editing yourself.  The bottom line, i.e., cost to
your organization in time and money, is best when NOT manually digitizing it
yourself.  Following that, GRASS is great for analysis!