coordinate systems used in GLIMS

[Hugh Kieffer (GD.Flagstaff) (928)556-7015]

Bruce:
 
The new proposal of course requires double precision. I agree that
conversion between geographic and mapping coordinates generally is not
impractical. I think arc interpolation is not as issue, as GLIMS
points will rarely be spaced by more than a few km, the fractional
error is roughly linear with spacing, and at 10 km is < 1.E-5 .

My sole remaining concern is tracking of absolute location uncertainty
and how to update all points associated with an image analysis when
the image location is improved by whatever means. If points remain
linked to their image origin, and the basis for locating that image is
tracked, then updates can be automated. Is this capability being built
into the GLIMS database?

Hugh

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Hugh H. Kieffer         hkieffer at flagmail.wr.usgs.gov
U.S. Geological Survey  Phone  928-556-7015
2255 N. Gemini Drive    FAX           -7014
Flagstaff, AZ 86001     Main Office   -7000 
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