[Proj] WGS84 to ED50

[Roger Oberholtzer]

I have a bit more information on the problem with WGS84 lat/longs ->
ED50(Spain) northings and eastings.

The software that is being used does not have a 'Spanish' setting. So
they have defined an ED50 7 parameter transform, with these
coefficients:


> International Ellipsoid 1924 definition
> Mayor semiaxle: 6378388
> Minor semiaxle:6356911,9461
> 1/f:297
> Excentricity: 0.0819910890032286
> 
> About the 7 parameters transformation 
> Translation X (m): 125.098545
> Translation Y (m): 76.000054
> Translation Z (m): 156.198703
> X Rotation(seconds): 0
> Y Rotation(seconds): 0
> Z Rotation(seconds): -1.129
> Scale factor (ppm): -8.30463103
> 
> This correspond with applanix header file saying 
> Mapping frame datum: ED50_ESPAÑA ; a = 6378388.000000; 1/f = 297.000000;
>  Coordinate transformation from WGS84 to mapping frame datum 
>     dX = 125.098545; dY = 76.000054; dZ = 156.198703; f = 0.999991695369; 
>     R1 = 0.000000000000; R2 = 0.000000000000; R3 = -0.000005473550;
>  sequence of the rotations: x,y,z,1 
>  Mapping frame projection : TM;
>  central meridian = -3.000000 deg;
>  latitude of the grid origin = 0.000000 deg; grid scale factor = 0.999600: 
>  false easting = 500000.000000 m; false northing = 0.000000 m; 
> 
>  
> Where Rotations are in radians 

I have tried setting proj to use this, as reported earlier in this thread, with no luck. I tried using the 7 parameters as 
+towgs84=125.098545,76.000054,156.198703,0.0,0.0,-1.129,-8.30463103, but that made things worse.

fromProj = pj_init_plus(
                        "+proj=latlong "
                        "+ellps=WGS84 "
                        "+no_defs");

toProj = pj_init_plus(
                        "+proj=utm "
                        "+ellps=intl "
                        "+k=0.999600 "
                        "+x_0=500000.0 "
                        "+y_0=0.0 "
                        "+zone=30 "
                        "+units=m"

"+towgs84=125.098545,76.000054,156.198703,0.0,0.0,-1.129,-8.30463103"
                        "+no_defs");

So I am guessing I cannot simply use the 7 parameters as given. Correct?



-- 
Roger Oberholtzer

OPQ Systems / Ramböll RST

Ramböll Sverige AB
Kapellgränd 7
P.O. Box 4205
SE-102 65 Stockholm, Sweden

Office: Int +46 8-615 60 20
Mobile: Int +46 70-815 1696