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State of Texas - Highlighting Low-Lying Areas Derived from USGS Digital Elevation Data

Scientific Investigations Map 3050

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Abstract

In support of U.S. Geological Survey (USGS) disaster preparedness efforts, this map depicts a color shaded relief representation of Texas and a grayscale relief of the surrounding areas. The first 30 feet of relief above mean sea level are displayed as brightly colored 5-foot elevation bands, which highlight low-elevation areas at a coarse spatial resolution. Standard USGS National Elevation Dataset (NED) 1 arc-second (nominally 30-meter) digital elevation model (DEM) data are the basis for the map, which is designed to be used at a broad scale and for informational purposes only. The NED data were derived from the original 1:24,000-scale USGS topographic map bare-earth contours, which were converted into gridded quadrangle-based DEM tiles at a constant post spacing (grid cell size) of either 30 meters (data before the mid-1990s) or 10 meters (mid-1990s and later data). These individual-quadrangle DEMs were then converted to spherical coordinates (latitude/longitude decimal degrees) and edge-matched to ensure seamlessness. The NED source data for this map consists of a mixture of 30-meter- and 10-meter-resolution DEMs. State and county boundary, hydrography, city, and road layers were modified from USGS National Atlas data downloaded in 2003. The NED data were downloaded in 2002. Shaded relief over Mexico was obtained from the USGS National Atlas.

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Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
State of Texas - Highlighting Low-Lying Areas Derived from USGS Digital Elevation Data
Series title:
Scientific Investigations Map
Series number:
3050
Edition:
Version 1.0
Year Published:
2008
Language:
ENGLISH
Publisher:
Geological Survey (U.S.)
Contributing office(s):
Central Region Geospatial Information Office
Description:
Map Sheet: 39 x 35 inches; Downloads Directory
Projection:
Albers Conic Equal Area
Scale:
700000
Additional Online Files(Y/N):
Y