We are trying to improve datum shift accuracy by replacing the values of
the TOWGS84 parameter with values from NTV2_0.GSB via JGridShift, then
removing the authority code from the datum in the wkt.
also, we're calculating the values like so,
public String togws84(CoordinateReferenceSystem nad27crs, Coordinate
orig, Coordinate shifted) throws NoSuchAuthorityCodeException,
FactoryException, TransformException {
CoordinateReferenceSystem geoCrsNAD83 = CRS.decode("EPSG:4326");
MathTransform transform = CRS.findMathTransform(geoCrsNAD83,
nad27crs, true);
Coordinate origMetres = new Coordinate();
Coordinate shiftedMetres = new Coordinate();
JTS.transform(orig, origMetres, transform);
JTS.transform(shifted, shiftedMetres, transform);
return "TOWGS84[ (origMetres.x-shiftedMetres.x) +", "+
(origMetres.y-shiftedMetres.y)+", 0.0]";
}
Is this the correct approach to using a grid shift?
Thanks
John
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