[Proj] WGS84 Lat Lon to XYZ convercion

support.mn at elisanet.fi support.mn at elisanet.fi
Fri Feb 1 04:12:52 EST 2008


It is not totally clear, what is the problem? That is how lat/lon projection works: it takes the lat and long coordinates and converts them directly to X and Y, your results are totally ok??

If you want to shift your local coordinates to WGS84 and then project them to lat/lon X-Y; you should tell the proj-4, that your coordinates are not in WGS84. In that case you will have 2 datums: the source datum, which is your local datum and that is shifted from WGS84; and the destination datum, which is the same as the WGS84. Then you first call the pj_transform() to do the datum conversion between those two datums and then you do the projection to lat/lon projection calling pj_fwd() in the destination datum and projection.

Regards: Janne.


Alekos Ntermaris <ntermaris at iqsoft.gr> kirjoitti: 
> I want to convert long ,lat , h  coordinates to X,Y, Z to WGS 84
> I Tried the definition of WGS84
> +proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs
> and having data
> l:20.6390537809385
> f:39.3094039129052
> h:523.563059728303
> calling pj_fwd
> the results
> x:20.6390537809385
> Y:39.3094039129052
> The same as input...
> Any suggestion for this transformation????
> Thanks
> Alex
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