Press Release

Pictures from the Real Edge: NASA Posts U.S. Topography Data

By SpaceRef Editor
January 23, 2002
Filed under , ,

Displaying spectacular new 3-D images and animations of
California from space, scientists at NASA’s Jet Propulsion
Laboratory (JPL), Pasadena, Calif., today 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.

“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 today’s 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

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 today’s 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:

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.

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

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.

SpaceRef staff editor.