[Proj] How to convert a sphere to ellipsoid with correct datum?

Hermann Peifer peifer at gmx.eu
Wed Sep 1 10:37:27 EST 2010

On 01/09/2010 12:54, Jan Hartmann wrote:
> The same location on the
> world globe has *different* latlong values when computed on the basis of
> different ellipsoids, and that is not shown by cs2cs.

I am not so sure about different *long* values. Anyway, can't you just 
convince cs2cs to do the calculation by putting +towgs84=0,0,0 on both 
sides of the equation?

$ cs2cs -v +proj=latlong +ellps=sphere +a=6371000 +towgs84=0,0,0 +to 
+proj=latlong +ellps=WGS84 +towgs84=0,0,0

# ---- From Coordinate System ----
#Lat/long (Geodetic alias)
# +proj=latlong +ellps=sphere +a=6371000 +towgs84=0,0,0
# ---- To Coordinate System ----
#Lat/long (Geodetic alias)
# +proj=latlong +ellps=WGS84 +towgs84=0,0,0
10 60
10dE    60d9'57.992"N 8919.390


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