[OSRS-PROJ] Datum transformation - more Sphere to WGS84...

Clifford J Mugnier cjmce at lsu.edu
Sun Mar 23 08:33:02 PST 2003


Sverre,

The solution to your problem is essentially an exercise in algebra.  There
is little practical value (that I can think of) for geodetic applications
in this case, but "cartographic license" can be always be invoked with a
bit of tongue-in-cheek ...

I suggest that you use the conversion from "geocentric latitude" to
"geodetic latitude" with whatever ellipsoid you choose.  There is no need
to "play" with the longitude values you have since the ellipsoid is a solid
of revolution and therefore already is a "spherical" function.

Cliff Mugnier
LOUISIANA STATE UNIVERSITY

--------------------------------------------

Hello GMT and PROJ.4 users:

Thank you for help and comments.

I need to convert the coordinates on a Spherical earth
(GMT ELLIPSOID: "Sphere", 1980, 6371008.7714, 6371008.7714, 0.0)
(e.g. Sandwell/Smith v.9.1 gravity data) to WGS84, but I
have problems finding the right transformation parameters.

* I have installed the USGS software PROJ.4 from
http://www.remotesensing.org/proj/
Program cs2cs supports tranformations between
different datums if you have the right paramters (towgs84)

* A comprehensive list of "towgs84" paramters is found
on http://mapserver.gis.umn.edu/doc36/proj.html
However, not Sphere to WGS84 can not be fond on this site
or other places I have looked on the internet.

Question:
Can anybody supply me with the right towgs84 paramters for
a translation from Sphere to WGS84?

Sincerely,

Sverre Planke
Volcanic Basin Petroleum Research AS
Forskningsparken, Gaustadalleen 21
0349 Oslo, Norway


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