[Proj] Re: WGS84 Lat Lon to XYZ convercion

Alekos Ntermaris ntermaris at iqsoft.gr
Fri Feb 1 04:24:21 EST 2008


The problem is that using the pj_fwd function i get the same results as 
the input ( lon , lat) and not XYZ....

Thanks Alex

O/H support.mn at elisanet.fi έγραψε:
> Hello,
> 
> 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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> 
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