[Geoserver-users] Purpose of TOWGS

GeoServer GeoServer User
1

In the description of how to create a custom projection, there is something labeled TOWGS. What is this?

2

Amy Johnson ha scritto:

In the description of how to create a custom projection, there is something labeled TOWGS. What is this?

Bursa Wolf transform parameters needed to go from one ellipsoid
to the reference one, WGS84 (thus "to WGS").
You don't need them if your reference system is based on the WGS84
ellipsoid, otherwise they are needed if you need to perform a transform
between your CRS and another specified with a different ellipsoid.

See also:
http://udig.refractions.net/docs/api-geotools/org/geotools/referencing/datum/BursaWolfParameters.html

Hope this helps
Cheers
Andrea