This geologic map was prepared as a part of a study of digital
methods and techniques as applied to complex geologic maps. The
geologic map was digitized from the original scribe sheets used to
prepare the published Geologic Map of Colorado (Tweto 1979).
Consequently the digital version is at 1:500,000 scale using the
Lambert Conformal Conic map projection parameters of the state base
map. Stable base contact prints of the scribe sheets were scanned on
a Tektronix 4991 digital scanner. The scanner automatically converts
the scanned image to an ASCII vector format. These vectors were
transferred to a VAX minicomputer, where they were then loaded into
ARC/INFO. Each vector and polygon was given attributes derived from
the original 1979 geologic map.
This database was developed on a MicroVAX computer system using VAX
V 5.4 nd ARC/INFO 5.0 software.
UPDATE: April 1995,
The update was done solely for the purpose of adding the abilitly to
plot to an HP650c plotter. Two new ARC/INFO plot AMLs along with a lineset
and shadeset for the HP650C design jet printer have been included. These
new files are COLORADO.650, INDEX.650, TWETOLIN.E00 and TWETOSHD.E00. These
files were created on a UNIX platform with ARC/INFO 6.1.2. Updated versions
of INDEX.E00, CONTACT.E00, LINE.E00, DECO.E00 and BORDER.E00 files that
included the newly defined HP650c items are also included.
* Any use of trade, product, or firm names is for descriptive purposes
only and does not imply endorsement by the U.S. Government.
The Digital Geologic Map of Colorado in ARC/INFO Format
Open-File Report 92-050
Additional publication details
USGS Numbered Series
The digital geologic map of Colorado in ARC/INFO format