DLG3 o Format description?

[GEOL1 at CWU.EDU]

For DLG-3 Optional format description or other info related to USGS
map products call (800)USA-MAPS.  There are low cost manuals on
DLG-3 for the 1:100000 and 1:24000 scales; either one will give the
basic format description in great detail.  If you write export routines
to convert vector maps to DLG-3, please observe the details in these
documents so others will have a good chance to import your data 
(independent of which GIS they use).  Too many folks have modified
the DLG-3 standard format and then distribute data that no one else
can reliably read.

Jim Hinthorne
GIS Lab
CWU