  The datum of Digital Elevation Model of Antarctica, provided there, derived from raster
data of GTOPO30 project, distributed by the USGS EROS data center. Base resolution of the
datum is 1km. The data uses Polar Stereographic Projection with true scale latitude of -71°.
  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 
Antarctica, mainly in respect of ocean features and ice shelves.

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