Hi Rich,
Glad to see that something/anything comes up at this early point.
It would be nice to figure out the georeferencing issue. I suppose I
could reproject all this stuff into something that is more readily
handled (like geographic coordinates? not sure that ArcInfo will go to
albers on a sphere...) and then convert again to netcdf. Probably good
to think a few minutes before undertaking that.
Roland
From: Rich Signell <rsignell@xxxxxxxx>
To: Roland Viger <rviger@xxxxxxxx>
Cc: John Caron <caron@xxxxxxxxxxxxxxxx>
Date: 10/08/2009 03:29 PM
Subject: Problem with Albers and Spherical Earth
Sent by: rsignell@xxxxxxxxx
------------------------------------------------------------------------
Roland,
Attached is the NcML for your uniformly spaced Albers Equal Area
Delaware grid, and while NetCDF-Java figured out the geospatial
coordinates, it didn't plot in exactly the right place (see
attached).
Do you think folks will mind? ;-)
I figured that this was probably an ellipsoid issue, realizing that I
hadn't specified a datum or ellipsoid.
But then I discovered (remembered?) that it isn't possible to specify
anything -- the Unidata Common Data Model assumes a spherical earth
for Albers
http://www.unidata.ucar.edu/software/netcdf-java/reference/StandardCoordinateTransforms.html
and of course this data uses the GRS80 Spheroid. ;-(
I tried adding an inverse_flattening, hopefully, but nothing happened,
so I guess the Albers Equal Area routine would have to be improved for
this to work correctly.
John, please correct me if I'm wrong.
-Rich
--
Dr. Richard P. Signell (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598
[attachment "2009-10-08_1650.png" deleted by Roland
Viger/WRD/USGS/DOI] [attachment "de.ncml" deleted by Roland
Viger/WRD/USGS/DOI]
