  The datum of Digital Elevation Model of Earth, provided there, derived from raster 
data of GTOPO30 project, distributed by the USGS EROS data center. Base resolution 
of the datum is 30". Also the datum populated with data from USGS DEM 1 Quads with 
resolution 3" for Alaska, Aleutian Islands and Hawaii.
  The datum presented here generally in form of .ZRS-files (stands Zipped Raster Set), 
which is proprietary compressed format of author of the datum. Separated files of 
the datum are in hierarchical and multi-resolution relation for optimization of speed 
and appearance upon using in Spatial Aspect Viewer and Spatial Aspect Explorer 
software products of author.
  Also the datum contents set of spatial regions covering main geographical features of 
Earth, including continents, separated mountains, ranges, peninsulas, selected areas, 
islands and lakes.


See site of author: www.runspect.com for more details.
Copyright (c) 2011-2016 Yuri Feldman
