THE EROS DATA CENTER: A PARTNER IN INTERNATIONAL REMOTE SENSING
Glenn H. Landis
Deputy Chief, EROS Data Center
U.S. Geological Survey
Sioux Falls, South Dakota 57198
Introduction
The United States Department of the Interior's EROS Data Center is
assuming an expanded role in support of the Landsat system within the
U.S. and is planning to increase its support of the international
community of Landsat data users in cooperation with the ground station
operators throughout the world.
Improved Data Processing
The Data Center is entering into a partnership with the National
Aeronautics and Space Administration to implement an improved system
for processing Landsat data. The system will provide products with
superior radiometric and geometric properties and will allow us to be
more responsive to users requirements in data formatting and timeliness
of delivery.
The total system is composed of two elements, one being installed at the
Goddard Space Flight Center (GSFC) and the other at the EROS Data Center
(EDC). Frequently the two elements are described as separate systems
called the Image Processing Facility (IPF) for the GSFC element and
EROS Digital Image Processing System (EDIPS) for the EDC element;
together they work as a single system with an interface of high density
digital tapes between the elements.
The IPF at GSFC assembles the data acquired by the three U.S. receiving
Stations, merges the raw data with ephemeris, altitude, sensor calibration
and ground control point data to Produce a radiometrically and
geometrically corrected output product. The standard tape transmitted
to EDC will contain data geometrically adjusted to fit a Hotine Oblique
Mercator (HOM) projection using a cubic convolution resampling algorithm.
The EDC element of the system further processes the data that are
received on the high density digital tape, applying selectable radiometric
manipulation algorithms to image data, and producing film and computer
compatible tapes for distribution to users. For reasons of economy,
EDC's basic strategy is to "pipeline" process all data to 1:1,000,000
black and white film for archiving and use for photographic reproduction.
This enables us to continue to offer standard photographic products at
existing prices. Initially the radiometric manipulation for the standard
product will be limited to a contrast stretch algorithm that spreads the
brightness values in each band to the useable density range of the film
used for recording. Edge enhancement algorithms will not be routinely
applied. As we learn more about user reaction to the product, the
processing parameters may be modified.