Mexico Data

Hi Folks!
I am in search of digital data for the Tabasco and Chiapas provences of
southern Mexico. Specifically in the area between Villahormosa and
Tuxla. Elevation models (DEM), Line Graphs of roads etc (DLG), geology,
hydrology, and any other "ologies" would be of value. This data will be
used in support of speleological research in the area.
Thanks in advance,
Doug Dotson
dotson@clark.net