Geologic Map and Digital Database of the Apache Canyon 7.5' Quadrangle, Ventura and Kern Counties, California, USGS OFR 00-359

The data set for the Apache Canyon quadrangle has been prepared by the
Southern California Areal Mapping Project (SCAMP), a cooperative project
sponsored jointly by the U.S. Geological Survey and the California Division of
Mines and Geology, as part of an ongoing effort to utilize a Geographical
Information System (GIS) format to create a regional digital geologic database
for southern California. This regional database is being developed as a
contribution to the National Geologic Map Data Base of the National Cooperative
Geologic Mapping Program of the USGS.

The digital geologic map database for the Apache Canyon quadrangle has been
created as a general-purpose data set that is applicable to other land-related
investigations in the earth and biological sciences. The Apache Canyon
database is not suitable for site-specific geologic evaluations at scales
greater than 1:24,000 (1 in = 2,000 ft).

This data set maps and describes the geology of the Apache Canyon 7.5'
quadrangle, Ventura and Kern Counties, California. Created using Environmental
Systems Research Institute's ARC/INFO software, the data base consists of the
following items: (1) a map coverage showing geologic contacts, faults and
units, (2) a separate coverage layer showing structural data, (3) an additional
point coverage which contains bedding data, (4) a point coverage containing
sample localities, (5) a scanned topographic base at a scale of 1:24,000, and
(6) attribute tables for geologic units (polygons), contacts (arcs), and
site-specific data (points). The data base is accompanied by a readme file and
this metadata file. In addition, the data set includes the following graphic
and text products: (1) A jpg file (.jpg) containing a browse-graphic of the
geologic map on a 1:24,000 topographic base. The map is accompanied by a
marginal explanation consisting of a List of Map Units, a Correlation of Map
Units, and a key to point and line symbols. (2) A .pdf file of a geologic
explanation pamphlet that includes a Description of Map Units. (3) Two
postScript graphic plot-files: one containing the geologic map on a 1:24,000
topographic base and the other, three accompanying structural cross sections.

The geologic map database contains original U.S. Geological Survey data
generated by detailed field observation and by interpretation of aerial
photographs. The map was created by transferring lines and point data from the
aerial photographs to a 1:24,000 topographic base by using a PG-2 plotter. The
map was scribed, scanned, and imported into ARC/INFO, where the database was
built. Within the database, geologic contacts are represented as lines (arcs),
geologic units as polygons, and site-specific data as points. Polygon, arc, and
point attribute tables (.pat, .aat, and .pat, respectively) uniquely identify
each geologic datum and link it to other tables (.rel) that provide more
detailed geologic information.