Global Imagery Can Be Directly Used in Any ArcGIS Product and Is Available Via ArcWeb Services
Natural Color Imagery Available at 15-Meter (0.5-Arcsecond) Resolution
Global, affordably priced, image data products are now available at 15-meter (0.5-arcsecond) pixel resolution (equivalent to a scale of about 1:50,000). With a circa year 2000 acquisition date and a geodetic positional accuracy of 50 meters RMSEr, these Landsat-based image data sets provide excellent logistical and geodetic reference informationanywhere on the globefor a wide variety of GIS and simulation applications. NaturalVue, developed by Esri Business Partner Earth Satellite Corporation (EarthSat) is the only global natural color image mosaic at any resolution less than 450 m.
The 2004 release of ArcGIS 9 3D Analyst featuring ArcGlobe includes a 150-meter (5.0-arcsecond) version of this unique global image data set that is excellent at 1:500,000 scale. The 15-meter NaturalVue zooms in to 1:50,000 scale, and features are sharp and crisp.
In the summer of 1997, EarthSat, located in Rockville, Maryland, began working under a National Aeronautics and Space Administration contract to create a global mosaic of Landsat digital multispectral image data. By the end of 2003, EarthSat had processed the globe three times, using three separate epochs of Landsat digital data. The earliest data set consisted of mid to late 1970's vintage Landsat Multispectral Scanner (MSS, at 57-meter resolution) data, the middle epoch consisted of circa year 1990 Landsat Thematic Mapper (TM, at 28.5-meter resolution), and the latest epoch was circa year 2000 Landsat Enhanced Thematic Mapper (ETM, at 14.25-meter resolution). More than 24,000 Landsat scenes were orthorectified.
A rigorous photogrammetric block adjustment, leveraging highly accurate horizontal and vertical control, provided by the U.S. government was used to orthorectify the circa 1990 Landsat TM scenes to a Universal Transverse Mercator WGS84 projection with an RMSEr accuracy of better than 50 meters. The resulting orthorectified Landsat scenes, along with the government-provided vertical control, were then used to precision orthorectify the 1970's vintage MSS and year 2000 vintage ETM Landsat image data. The result is a global three-epoch suite of tightly coregistered, geodetically accurate, Landsat multispectral data sets.
The circa year 2000 epoch of Landsat ETM multispectral data has the most complete global coverage, extending across all of the major ocean islands, with Antarctica being the only significant land area not covered. All of the more than 8,500 scenes comprising the ETM data set were pan-sharpened to a 14.25-meter resolution and processed through an EarthSat proprietary algorithm to create a Synthetic Natural Color (SNC) color composite. The SNC process is specially tuned to avoid the atmospheric haze distortions that are common with other forms of Landsat-based natural color imagery.
The final NaturalVue product has been carefully color balanced and seamlessly mosaicked into a complete, consistent global coverage in a geographic (latitude/longitude) WGS84 geometry with a 0.5-arcsecond (15-meter) pixel size and a positional accuracy of 50-meter RMSEr.
The complete 0.5-arcsecond NaturalVue product, all 4.5 terabytes of raster data, has been loaded into a geodatabase using ArcSDE with Oracle that is actively serving both thin (Internet browser) and thick (GIS) clients. Thick clients include ArcGIS Desktop and ArcGIS 3D Analyst.
Some of the current applications of NaturalVue include GIS backdrop, flight simulation, mission planning, in-flight position tracking, mapping coastlines, natural resource mapping and planning, news and weather broadcast, print publication, geography education, and global reference atlas.
NaturalVue is currently available in 5 x 6 degree GeoTIFF tiles; each tile is approximately 300,000 square kilometers and four gigabytes. A tile covers an area equal to approximately 10 Landsat TM scenes. It takes approximately 800 tiles for the global data set, approximately 4.5 terabytes. Prices begin at $150 per tile for a single seat license. Multiseat and agencywide licenses are also available.
For more information on purchasing NaturalVue, contact Esri at 1-800-447-9778. In the near future, NaturalVue 2000 will be served from a Web environment for both browser and GIS access.
For more information, contact Roger Mitchell, vice president, Program Development, Earth Satellite Corporation (tel.: 240-833-8206 or 240-833-8200, e-mail: firstname.lastname@example.org, Web: www.earthsat.com).