U.S. topography data from shuttle mission unveiled
Posted: January 23, 2002

Displaying spectacular new 3-D images and animations of California from space, scientists at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., Tuesday announced the release of high-resolution topographic data of the continental United States gathered during the February 2000 Shuttle Radar Topography Mission (SRTM) -- a mission that is creating the world's best topographic map.

Mount San Antonio, more commonly known as Mount Baldy, crowns the San Gabriel Mountains northeast of Los Angeles in this computer-generated east-northeast perspective viewed from above the Malibu coastline. On the right, the Pacific Ocean and Santa Monica are in the foreground. Further away are downtown Los Angeles (appearing grey) and then the San Gabriel Valley, which lies adjacent to the mountain front. The San Fernando Valley appears in the left foreground, separated from the ocean by the Santa Monica Mountains. This 3-D perspective view was generated using topographic data from SRTM, an enhanced color Landsat 7 satellite image, and a false sky. Credit: NASA
"The release of the California mosaic and continental-U.S. SRTM data is a tantalizing preview of things to come from this program," said Michael Kobrick, JPL SRTM project scientist. "We are processing data for the rest of the world on a continent- by-continent basis, mapping and exploring many relatively unknown regions where our maps will be far more precise than the best global maps in use today."

Yunjin Kim, JPL SRTM project manager, said users in the U.S. and elsewhere would find wide applications for the data. "The maps produced from the mission will be among the most valuable, universally beneficial data ever produced by a science mission. National and local government organizations, scientists, commercial enterprises and civilians alike will find the data useful for applications as diverse as earthquake studies, flood control, transportation and urban planning, enhanced ground- collision warning systems for aircraft and better placement of cell phone towers," he explained.

With this 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 general 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 80 percent of Earth's land mass 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.

Thomas A. Hennig, National Imaging and Mapping Agency's (NIMA) program manager for SRTM said, "SRTM literally captured a snapshot of the Earth's surface at the beginning of the 21st century that will be of tremendous value for years to come. The SRTM data will provide NIMA's customers a revolutionary leap forward in imaging information." NIMA partnered with NASA, Germany and Italy in sponsorship of the SRTM flight.

The centerpiece of this 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 NIMA for final quality checking and copies sent to the United States Geological Survey's EROS Data Center, Sioux Falls, S.D., for final archiving and distribution.

At more than 4,300 meters (14,000 feet), Mount Shasta is California's tallest volcano and part of the Cascade chain of volcanoes extending south from Washington. This computer-generated perspective viewed from the west also includes Shastina, a slightly smaller volcanic cone left of Shasta's summit and Black Butte, another volcano in the right foreground. This 3-D perspective view was generated using topographic data from SRTM and an enhanced color Landsat 5 satellite image. Topographic expression is exaggerated two times. Credit: NASA
The SRTM was flown aboard Space Shuttle Endeavour Feb. 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 (197-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices.

The SRTM mission supports NASA's Earth Science Enterprise, Washington, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.