[GRASSLIST:4100] Spherical earth

[Charles Krouse]

I want to import and use NOAA CoastWatch sst raster data.  It is 
projected in mercator with a spherical earth with a radius of 
6371200.0m.  I thought that I had it defined but it appears a sphere can 
not be used.  After the mercator projection and shpere definition, I get the following

projection: 99 (Mercator)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  ** unknown (default: WGS84) **


When displaying the data with this projection, it is obviously not accurate for the CoastWatch projection, and it appears to have used WGS84 as the default 
ellipsoid.

Can anyone sugguest a work around?  Possibly define a = b in the 
ellipse.table?   This method worked in other software that we used.  


Thanks.

                                                                        
                                                Charlie