[Proj] Can I convert the ellipsoids using Proj?

[Noel Zinn (cc)]

Cleo,

FAQ #7 under Altimetry products in the link you provide seems to answer the question you ask.  The FTP link in that paragraph leads you to  a program top2wgs.pro that solves your problem.  The program assumes dX = dY = dZ = 0.  I’ve made the same assumption myself with TOPEX/Poseidon in a different context.  Then follow Jose’s cs2cs instructions.

Thanks for the link.

Noel

Noel Zinn, Principal, Hydrometronics LLC
+1-832-539-1472 (office), +1-281-221-0051 (cell)
noel.zinn at hydrometronics.com (email)
http://www.hydrometronics.com (website)


From: Cleo Drakos 
Sent: Tuesday, August 19, 2014 3:39 AM
To: PROJ.4 and general Projections Discussions 
Subject: Re: [Proj] Can I convert the ellipsoids using Proj?

Dear Jose

Thanks for your answer. Can you help me how can I make certain that both ellepsoids have the same geocentric coordinates.
Only the information I am having is below under the section of How does the GLAS ellipsoid compare with WGS 84?


http://nsidc.org/data/icesat/faq.html#3_all 


cleo



On Tue, Aug 19, 2014 at 6:03 AM, Jose Gonçalves <jagoncal at gmail.com> wrote:

  Cleo

  If cartesian geocentric coordinates are the same and you just want to express them in a different ellipsoid you can do:

  cs2cs -f %.9f +a=6378136.30 +rf=298.257 +proj=latlong +towgs84=0,0,0 +to +a=6378137 +rf=298.25722356 +proj=latlong +towgs84=0,0,0


  If there are shift and rotation you can express them in the +towgs84.


  Regards


  José 





  2014-08-18 15:13 GMT+01:00 Cleo Drakos <cleo21drakos at gmail.com>:

    Dear guys,

    I have the data (latitudes, longitudes, and elevations) given in ICESat/GLAS ellipsoid. This equatorial radius and  reciprocal flattening (1/f) on this ellipsoid are 6378136.30 m and is 298.257 respectively.

    Now, I want to convert my data into WGS84 ellepsoid with equatorial radius and reciprocal flattening (1/f) of 6378137.000000 and 298.25722356 respectively.

    Can I convert the ellipsoids using Proj?

    I hope some of you can help me.


    cleo

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