[Proj] help with proj.4

[Frank Warmerdam]

On 11-06-13 10:36 AM, zagot wrote:
> Hi to all
>
> if i run this with cs2cs
>
> cs2cs +proj=tmerc +lat_0=0 +lon_0=-3.45233333333333 +k=0.999600 +x_0=1500000
> +y_0=0 +ellps=intl +pm=rome +units=m
> +towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68
> +to +proj=latlong +datum=WGS84
> 1514905.27  5034551.13
>
> i have this result
>
> 3d15'42.057"W 45d27'48.522"N 0.00
>
> i need to do this with programmatic but with this code
>
> char proj4Gauss[]="+proj=tmerc +lat_0=0 +lon_0=-3.45233333333333 +k=0.999600
> +x_0=1500000 +y_0=0 +ellps=intl +pm=rome +units=m
> +towgs84=-104.1,-49.1,-9.9,0.971,-2.917,0.714,-11.68";
>
> char projWgs84[]="+proj=latlong +datum=WGS84 ";
> 	
> projPJ projGauss = pj_init_plus(proj4Gauss);
> 	
> double x=1514905.27 ;
> double y=5034551.13;
> double z=0;
>
> double ris = pj_transform(projGauss, projWgs84, 1, 0,&x,&y,&z);
>
> i have this result (in decimals point)
>
> 4423479.3363604508      715679.13023441052
>
> waths I wrong? in the source code

Zagot,

Are you really passing a string valued projWgs84 to pj_transform()
directly without first turning it into a projPJ structure using
pj_init_plus() like you did for the projGauss?  If so, it's a wonder
things didn't crash.

Otherwise, I don't see any obvious problem.  Do be aware that geographic
coordinates will be in radians, not decimal degrees so you will need to
adjust for that.  But the values you are getting back are clearly not
radians.

Best regards,

-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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