Position Integrity terrain datasets will shortly be available for
public release and will be tightly integrated with our free moving
map applications, Digital Aviator and
In 1999, Position Integrity was chosen as the terrain database
providers for the NASA-Langley Aviation Safety Program (ASP).
Under a team effort entitled Low Cost Synthetic Vision Capability
for General Aviation, we are providing a global terrain database
for use in the next generation 3D perspective glass cockpit display
system. The team, which is headed up by Research Triangle
Institute for Aerospace Technology and includes several prominent
industry members, will begin flight testing our innovations early in 2001.
In addition to our work for NASA-Langley, we have been collaborating
with the NASA/Jet Propulsion Laboratory in Pasadena for the last seven
years on advanced terrain graphics research. JPL's Shuttle Radar
Topography Mission (SRTM), was launched on the Shuttle Endeavour
STS-99 manifest and mapped the earth in eleven days from February
11-22, 2000. The SRTM radar, with its long wavelength, was able to
penetrate clouds as well providing its own illumination, making
measurements independent of daylight.
One scientific threshold which was surpassed this year is the
proof that single-pass, multi-frequency, multi-polarization radar
holography is now a reality! From the 222 hours of continuous
mapping, there are some 12 terabytes of raw data in the form of
3D "radar holograms" to process. The focus now shifts from the
Shuttle flight to the ground data processing at JPL in Pasadena.
SRTM has collected data over most of the land surfaces that lay
between 60 degrees north latitude and 54 degrees south latitude.
That's about 80% of all the land on the Earth. SRTM project scientist
Dr. Michael Kobrick (from NASA/JPL) notes that Endeavour mapped an
incredible 100,000 square kilometers every minute, and that after
only three days of flight, the mission tripled the world's supply of
digital terrain elevation data. The low-resolution images processed
so far show many topographic features that until now have been
difficult to detect on the best maps in existence today.
After mission completion, JPL began focusing on ground data processing
activities for the equatorial regions of the earth, for which our
terrain knowledge is the sparsest. The attached images show the final
coverage map and globes from the SRTM mission. In total 119.05 million
square kilometers were mapped with at least one interferometric pass,
which translates to 99.958% of the goal for the mission.
In addition 112.66 million square kilometers were mapped with at least
two passes, and many areas in the northern latitudes were covered
four or five times. (The number of passes over a sight correlates
with vertical height accuracy.)
Position Integrity is assisting in the ground data processing and has
the government contract to define and promulgate the next generation
graphics data format, called GeoTIFF 2.0. One of the hallmarks of the
new data from the shuttle is that JPL will process multiple resolutions
and products from any given geographic area. Before GeoTIFF 2.0, each
dataset would have to be in its own file and displayed separately in a
viewing application. With version 2.0 we will be able to combine terrain at
several resolutions along with shaded relief and other images of the
same area in one file as well as dynamiclly link to datasets across the Internet.
Our free aeronautical moving map application,
Digital Aviator will then efficiently and automatically zoom or
pan through any of the "layers" while keeping perfect control over
knowledge of the geography (especially the latitude, longitude and altitude of every pixel).
GeoTIFF 2.0 allows C- and X-band multi-resolution terrain data to
co-exist along with radar backscatter, 3D anaglyphs, land use
classification, Landsat 7 multi-spectral imagery and NIMA cartographic
datasets all within the same file structure. With GeoTIFF 2.0 a user
will have access to all these multi-scaled, nested, tiled, gridded
and compressed images for a geographic region within a single file.
Over the next year we will begin to release prototype SRTM terrain
and imagery products in GeoTIFF 2.0 format. Since the SRTM derivative products
will be one of the most valuable GIS collections to come from the
scientific community in many decades, it is appropriate that
Position Integrity GeoTIFF 2.0 technology help herald its public release.
For more information on our terrain initiatives, please contact us
by telephone or email, or visit
the NASA SRTM Home Page.