[CF-metadata] What do models assume for the shape of the Earth?

Rich Signell rsignell at usgs.gov
Thu Apr 7 11:50:49 MDT 2005

Karl Taylor wrote:

> What would be important to know as models go to higher resolutions is 
> how the topography is specified in the model.  My understanding is that 
> modelers simply transfer the latitude/longitude locations of 
> topographical features and surface characteristics from the 
> non-spherical earth to his idealized spherical model earth without 
> correction. 

Our coastal hydrodynamic models have horizontal grid resolutions down to a few 
meters.   When we ingest lon,lat topography points, we are *very* careful of 
where they came from.  We just had to convert a bunch of longitude and latitute 
points from the Croatian national charts because they used a Bessell ellipsoid, 
which had resulted in a 200 m offset from the rest of our WGS84-ellipsoid 
lon,lat topography data.


Richard P. Signell           rsignell at usgs.gov
U.S. Geological Survey       Phone: (508) 457-2229
384 Woods Hole Road          Fax:   (508) 457-2310
Woods Hole, MA  02543-1598

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