[Proj] Hough Ellipse
Irwin Scollar
al001 at uni-koeln.de
Sat May 10 08:29:30 PDT 2014
I am working on a program for geometric
correction of the Corona KH4, 4A and 4B satellite
imagery which was declassified in 1995 and is now
available from the web site of the USGS & EROS data center.
https://lta.cr.usgs.gov/declass_1
The panoramic image strips cover vast areas of
roughly 3000 sq. km at 2 to 4 meters per pixel,
depending on the satellite height. USGS supplies
a metadata file with the corner and center points
of each image given in latitude and longitudes.
In
Image Coverage Models for Declassified Corona,
Argon and Lanyard Satellite Photography, A
Techical Expanation by J. Michael Sélander, in:
CORONA: Between the Sun & the Earth: The First
NRO Reconnaissance Eye in Space. Robert McDonald,
ed. Bethesda, Md.: ASPRS, 1997.
on page 181, it is stated that the coordinate
database uses the Hough Ellipsoid (1960). :
Parameters are given for this ellipsoid in the table:
http://geoengine.nga.mil/geospatial/SW_TOOLS/NIMAMUSE/webinter/geotrans2/help/elliptab.htm
Although called Hough in honor of F. Hough, it
appears to have been the work of that remarkable
lady Dr. Irene Fischer who lived to be 102 and
see her work incorporated into WGS84. See:
http://en.wikipedia.org/wiki/Irene_Fischer
Fischer, Irene. 1959. "A Tentative World Datum
from Geoidal Heights Based on the Hough Ellipsoid
and the Columbus Geoid". Journal of Geophysical Research. 64 (1): 73-84
Can anyone offer some ideas about the amount of
error which would be introduced by mixing Hough
lat/lons and WGS84 lat/lons obtained from Google
Maps/ Google Earth when georeferencing the Corona
imagery for further processing in GIS
programs? Or are Bursa-Wulff or Helmert datum
transformation parameters available somewhere?
Irwin Scollar
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