Geologic Shaded Relief Map of Venezuela

The geologic shaded relief map of Venezuela was created by direct digitization
of geologic and hydrologic data north of the Orinoco River from a 1:500,000
scale paper map set. These data were integrated with a digital geologic map of
the Venezuela Guayana Shield, also derived from 1:500,000 scale paper maps.
Fault type information portrayed on the map, including unlabeled fault types,
are as depicted in the original data sources. Geologic polygons were attributed
for age, name, and lithologic type following the Lexico Estratigrafico de
Venezuela. Significant revisions to the geology of the Cordillera de la Costa
were incorporated based on new, detailed (1:25,000 scale) geologic mapping.
Geologic polygons and fold and fault lines were draped over a shaded relief
image produced by processing 90 m (3-arc second) radar interferometric data
obtained by the space shuttle radar topography mission (SRTM). Values for
null-data areas inherent in the SRTM data set were filled by interpolation
based on surrounding data cells. The digital elevation model data was
hill-shaded using an illumination direction of 315 degrees at an angle of 65
degrees above the horizon to produce the shaded relief image. The map
projection used is equidistant conic, with latitudes 4 and 9 degrees north as
standard parallels, and longitude 66 degrees west as the central meridian.

The data contained in this map compilation primarily was derived from 1:500,000
scale maps and arranged for presentation and use at the scale of 1:750,000.
Users may zoom in to view greater detail at larger scale; however, the authors
make no guarantee of the accuracy of the map representation at scales larger
than 1:750,000.

[Summary provided by the USGS.]