Transform coordinates from Gauss-Kruger 2 / 3

Sep 11, 2013 at 4:09 PM
HELP!

I integrated Proj.Net into my project in order to transform coordinates. That works well with transforming WGS84 (ProjNet.CoordinateSystems.GeographicCoordinateSystem.WGS84) to UTM32 (ProjNet.CoordinateSystems.ProjectedCoordinateSystem.WGS84_UTM(32, True)).

It does not work with coordinates Gauss-Kruger 2 (EPSG:31466) and Gauss-Kruger 3 (EPSG:31467). I tried it by using

ProjNet.Converters.WellKnownText.CoordinateSystemWktReader.Parse(GK2WKT)
ProjNet.Converters.WellKnownText.CoordinateSystemWktReader.Parse(GK3WKT)

with GK2WKT

"PROJCS[""DHDN / Gauss-Kruger zone 2"",GEOGCS[""DHDN"",DATUM[""D_Deutsches_Hauptdreiecksnetz"",SPHEROID[""Bessel_1841"",6377397.155,299.1528128]],PRIMEM[""Greenwich"",0],UNIT[""Degree"",0.017453292519943295]],PROJECTION[""gauss_kruger""],PARAMETER[""latitude_of_origin"",0],PARAMETER[""central_meridian"",6],PARAMETER[""scale_factor"",1],PARAMETER[""false_easting"",2500000],PARAMETER[""false_northing"",0],UNIT[""Meter"",1]]"

and GK3WKT

"PROJCS[""DHDN / Gauss-Kruger zone 3"",GEOGCS[""DHDN"",DATUM[""D_Deutsches_Hauptdreiecksnetz"",SPHEROID[""Bessel_1841"",6377397.155,299.1528128]],PRIMEM[""Greenwich"",0],UNIT[""Degree"",0.017453292519943295]],PROJECTION[""gauss_kruger""],PARAMETER[""latitude_of_origin"",0],PARAMETER[""central_meridian"",9],PARAMETER[""scale_factor"",1],PARAMETER[""false_easting"",3500000],PARAMETER[""false_northing"",0],UNIT[""Meter"",1]]"

An error occured: Projection Gauss_Kruger is not supported.

I found the WKT unter http://www.spatialreference.org/ref/epsg/31467/html/ with projection as "Transverse_Mercator". No error occures but results are up to a few hundred meters displaced. For example:

Longitude 6.44990719188124
Latitude 50.5296161746303

should be transformed to

Gauss-Kruger 2 east (rechtswert): 2531944.721598
Gauss-Kruger 2 north (hochwert): 5599416,36501248

results i get are

Gauss-Kruger 2 east (rechtswert): 2531987.14052421
Gauss-Kruger 2 north (hochwert): 5599215,64379288

With a few centimeters i can live, 200m are too much!

Any suggestions?
Oct 29, 2013 at 4:13 PM
Edited Oct 29, 2013 at 4:20 PM
Do you found any solution for this problem? I have the same problem using GK4 (see SharpMap-Toppic Displaced Vector Data with OSM background layer)
Oct 30, 2013 at 11:28 AM
Nop, still haven't found what i was looking for;-(((
Coordinator
Oct 30, 2013 at 2:43 PM
try with this suggestion from here

You may want to replace the content of the prj file with the "postgis" definition of EPSG:31468
PROJCS["DHDN / 3-degree Gauss-Kruger zone 4",GEOGCS["DHDN",DATUM["Deutsches_Hauptdreiecksnetz",SPHEROID["Bessel 1841",6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],TOWGS84[598.1,73.7,418.2,0.202,0.045,-2.455,6.7],AUTHORITY["EPSG","6314"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4314"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",12],PARAMETER["scale_factor",1],PARAMETER["false_easting",4500000],PARAMETER["false_northing",0],AUTHORITY["EPSG","31468"],AXIS["X",NORTH],AXIS["Y",EAST]]
Oct 31, 2013 at 1:38 PM
Hi all, i got the same hint to use postgis-definitions for EPSG:31466 / 31467 and it really works mothers finest! Greetz & Thanx