NASA Posts U.S. Topography Data 01.28.2002
Displaying spectacular new 3-D images and animations of California from space, scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., released high-resolution topographic data of the continental United States gathered during the February 2000 Shuttle Radar Topography Mission -- a mission that is creating the world's best topographic map.
Dr. Yunjin Kim, mission project manager at JPL, said users in the United States and elsewhere would find wide applications for the data.
With the recent release, gigabytes of digital elevation-model data, sampled at an interval of one measurement every 30 meters (98 feet), are now available to selected science investigators, with 90-meter (295-foot) sample imagery available to the public. Processing and distribution of validated U.S. digital topographic data will continue on a regular basis, with completion expected this spring.
When completed in fall 2002, more than 12 terabytes of data encompassing nearly 1 trillion measurements will have been processed, representing the 80 percent of Earth's landmass between 60 degrees north and 56 degrees south of the equator. The areas mapped are home to approximately 95 percent of the world's population.
The centerpiece of the release is the California mosaic, a color-shaded relief elevation map. The image depicts California at a data-sample interval of 3 arc-seconds (approximately 90 meters or 295 feet). The map depicts changes in height as colors, with blues and greens at the lower elevations, rising through yellows and browns to white at the highest elevations. The California mosaic image and animations are available at: http://www.jpl.nasa.gov/srtm/ .
As processing of each continent is finished, data will be sent to the National Imaging and Mapping Agency for final quality checking and copies sent to the United States Geological Survey's Earth Resources Observation Systems Data Center, Sioux Falls, S.D., for final archiving and distribution.
The Shuttle Radar Topography Mission was flown aboard Space Shuttle Endeavour February 11-22, 2000. It used modified versions of the same instruments that comprised the Space Shuttle Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on Endeavour in 1994. The mission collected 3-D measurements of Earth's land surface using radar interferometry, which compares two radar images taken at slightly different locations to obtain elevation or surface-change information. To collect the data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices.
The Shuttle Radar Topography Mission supports NASA's Earth Science Enterprise, Washington, D.C., a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.