Geocover~(tm)-Ortho and Geocover~(tm)-Lc: Orthorectified Landsat Tm/Mss Data and Derived Land Cover for The World

摘要

Sponsored under NASA's Scientific Data Buy program, the GeoCover~(TM)-Ortho program has created a geodetically accurate digital database of Landsat TM and MSS multispectral imagery covering the earth's land mass. The GeoCover~(TM)-Ortho coverage is comprised of over 14,000 Landsat images that have been photogrammetrically adjusted and digitally orthorectified to create a seamless global coverage of multispectral digital imagery with 50 meter (RMS) geodetic positional accuracy. The Landsat source images have been hand picked from the Landsat archives of both the EGOS Data Center and international Landsat foreign ground receiving stations, and represent the highest image quality and lowest cloud cover available for the specified time period. GeoCover~(TM)-Ortho provides readily available, affordable, and accurate landsat TM and MSS multispectral imagery which not only can be used as a geodetically accurate base map, but also provide an excellent digital source for multispectral image processing and analysis. Working initially with NASA and currently with NIMA, EarthSat has developed a set of procedures and processes to produce a landcover analysis for all land areas of the world using Landsat TM data rectified under the GeoCover~(TM)-Ortho program. The 13 classes of land cover being mapped include: deciduous forest, evergreen forest, scrub/shrub, grassland, barren/sparsely vegetated, urban/built-up, rice agriculture, other agriculture, permanent herbaceous wetlands, mangroves, water, and ice/snow. The land cover from the first 1200 Landsat TM scenes covering the Middle East, East Africa, and North Africa will be available in May 2000. EarthSat owns the landcover product and the U.S. Government has purchased a government-wide license for the first 1200 scenes. Land cover from all 7,600 Landsat TM scenes should be completed in 2003. The land cover will be distributed in both raster and vector formats. The raster products will be available for each of the Landsat TM scenes and by 1-degree by 1-degree blocks. The vector products will be available by 1-degree by 1-degree blocks as ARC/INFO coverages.