LANDSAT ORTHO TM IMAGERY DATA SET ABSTRACT

This document provides information on an interim basis until a detailed Guide document becomes available.

Background. Data were compiled through NASA's Commercial Remote Sensing Program; this program is a cooperative effort between NASA and the commercial remote sensing community to provide users with access to quality-screened, high-resolution satellite images with global coverage over the Earth's land masses. The resulting EarthSat thematic mapper (TM) geocover data set contains orthorectified Landsat TM sensor data from the Landsat-4 and -5 satellites. Only the Landsat images that most closely met a specific set of criteria, including acquisition date, cloud percentage, data quality parameters, and best available phenology, were considered for the collection. The Landsat TM data were compiled through a NASA contract with Earth Satellite Corporation, Rockville, Maryland, and are part of NASA's Scientific Data Purchase program, developed in response to the President's Space Policy.

Data Set Characteristics. Approximately 7,461 Landsat TM images were selected. The acquisition dates of these images were relative to a 1990 acquisition baseline, and the images were either cloud-free or contained minimal cloud cover. In addition, only TM images with a high quality ranking in regards to the possible presence of errors such as missing scans or saturated bands were selected. It was important to collect data during periods of peak greenness so NASA adopted an approach for image selection that was based upon a data set containing global 1-kilometer advanced very high-resolution radiometer Normalized Difference Vegetation Index data. It was sometimes difficult for NASA to obtain clear images during time frames of peak greenness, resulting in some image substitution from other times of the year.

Processing. Landsat images were orthorectified, using geodetic and elevation control data to correct for positional accuracy and relief displacement. Large blocks of Landsat data were adjusted through a patented procedure that uses pixel correlation to acquire tie-points within the overlap area between adjacent Landsat images. Ground control points are fixed, and images are projected to the Universal Transverse Mercator map projection, using the World Geodetic System 1984 datum. All bands are individually resampled, using a nearest neighbor algorithm. The result is a final product with a Root Mean Square Error of better than 50 meters in positional accuracy.

Contacts for Data Center/Data Access Information:

Data Center Identification:

References:

Kalluri, Satya, Grant, Denelle, Tucker, Compton, Policelli, Fritz, Dykstra, Jon, and Bearden, Phil, 2000, NASA creates global archive of ortho-rectified Landsat data: EOS, Transactions, American Geophysical Union, v. 81, no. 50, p. 609, 617-618.

Disclaimer: Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Document Information:

Document Revision Date: December 22, 2003
Document Review Date: July 24, 2000
Document Curator: EDC staff
Document URL: http://eosims.cr.usgs.gov:5725/DATASET_DOCS/landsat_ortho_tm_dataset_abs.gd.html


Home	About	Products	Data Tools	Order Data	News	Help/Edu	Links	Contact Us

Landsat Orthorectified TM Imagery Data Set Abstract

Summary:

Contacts for Data Center/Data Access Information:

Data Center Identification:

References:

Document Information: