Convert from ED50 to WGS84 positions

[Solan]

Dear groupmemers,

I need to convert ED50 positions to WGS84. Has anyone written a matlab
function that can do that?

Nils Olav

[Rune Allnor]

I wouldn't be surprised if the mapping toolbox
contains such routines.

Rune

[Rob Comer]

Rune Allnor <all...@tele.ntnu.no> wrote in message <621d7f44-299a-496e...@a32g2000yqm.googlegroups.com>...

There is no Mapping Toolbox function to do the transformation in a single step, but the toolbox can help. The basic procedure is to:

1. Use the geodetic2ecef function with the ED50 reference ellipsoid to convert from ED50 latitude, longitude, and elllipsoidal height to X, Y, and Z in the corresponding earth-centered, earth-fixed geocentric system.

2. Apply a Helmert ("seven-parameter") transformation to transform X, Y, and Z to a WGS84 geocentric system. This is easy to code, but you'll need to look up a set of parameters somewhere (or fit them yourself if you have appropriate truth data).

3. Use the ecef2geodetic function with the WGS84 reference ellipsoid to convert from WGS84 X, Y, Z to WGS84 latitude, longitude, and ellipsoidal height.

Rob Comer
Mapping Toolbox Development
The MathWorks, Inc.

[Aolun Zhou]

"Rob Comer" <rob.come...@mathworks.com> wrote in message <hg1987$f90$1...@fred.mathworks.com>...

This looks like a perfect way, but what is the ED50 reference ellipsoid? The reference ellipsoid class doesn't have ED50 in its list, and Ed50 was reported as error when I simply typed in.

[Rob Comer]

"Aolun Zhou" wrote in message <n8a6tr$tv$1...@newscl01ah.mathworks.com>...

ED50 uses the International 1924 ellipsoid. For example, see:

http://georepository.com/datum_6230/European-Datum-1950.html

In Mapping Toolbox, use: referenceEllipsoid('International 1924')