[Proj] [delphi proj api]: Setting up TCoordinateTranslator
Christian Kirchhoff
ckirchho at directmedia.de
Fri Mar 7 12:36:30 EST 2008
Hello,
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:
PROJCS["Germany_Zone_3",GEOGCS["GCS_Deutsches_Hauptdreiecksnetz",DATUM["D_Deutsches_Hauptdreiecksnetz",SPHEROID["Bessel_1841",6377397.155,299.1528128]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",3500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",9.0],PARAMETER["Scale_Factor",1.0],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]
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,
5537463.422,0.00,0.00)
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
appreciated.
Regards,
Christian Kirchhoff
*Directmedia Publishing GmbH* · Möckernstraße 68 · 10965 Berlin
www.digitale-bibliothek.de
AG Berlin-Charlottenburg · HR B 58002 · USt.Id. DE173211737
Geschäftsführer: Ralf Szymanski · Erwin Jurschitza
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