[Proj] [delphi proj api]: Setting up TCoordinateTranslator

Christian Kirchhoff ckirchho at directmedia.de
Fri Mar 7 12:36:30 EST 2008


I'd like to use the Delphi PROJ API to translate coordinates. The 
coordinates come from GoogleMaps, thus are lat/lng values.

I want to match them to shapes from a shape file which I can read with 
the ShapeAPI. I have got the following information the the prj file of 
the shape:

Therefore I thought that the TCoordinateTranslator I named "Proj" should 
be opened with:
Proj.Open('+proj=tmerc +ellps=bessel +lon_0=9 +x_0=3500000');

...but I am not very familiar/experienced yet.

Anyway I have test coordinates from GoogleMaps, e.g. (50.1056069418592, 
8.404541015625). The region this coodinates lay in as exactly the region 
that is covered by shapes in the shape file. The bounds of the shape 
file are, according to what the ShapeAPI returned:
( 3394468.028, 5504381.719,0.00,0.00) to ( 3424916.697, 

But the translated Google coordinates are:
8451430,97 m, 1229074.77 m

Which is totally elsewhere.

My question is: Did I read the values from the shape's prj file wrong? 
Or did I use the wrong parameters when setting up the TCoordinateTranslator?

Any help for a better understanding of this matter would be greatly 


Christian Kirchhoff
*Directmedia Publishing GmbH* · Möckernstraße 68 · 10965 Berlin
AG Berlin-Charlottenburg · HR B 58002 · USt.Id. DE173211737
Geschäftsführer: Ralf Szymanski · Erwin Jurschitza
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