[OSRS-PROJ] datum-shift

Harald Wehr hwehr at hs-harz.de
Tue Feb 26 06:24:46 EST 2002

I want to convert some data from latlong/wgs84 to tmerc/bessel with 
datum shift from wgs84 to potsdam-datum here in germany.  How do i have 
to use the function? Are helmert-7-parameter as well as 
molodenski-3-parameter implemented? I tried the following:

cs2cs -v +proj=latlong +to +proj=tmerc +ellps=bessel +lat_0=0 +lon_0=12 
+x_0=4500000 +towgs84=-586,-87,-409 <<EOF
10.69079E 51.86134N

As result i get the following:

# ---- From Coordinate System ----
#Lat/long (Geodetic)

# +proj=latlong +ellps=WGS84
# ---- To Coordinate System ----
#Transverse Mercator
Cyl, Sph&Ell
# +proj=tmerc +ellps=bessel +lat_0=0 +lon_0=12 +x_0=4500000
# +towgs84=-586,-87,-409
#--- following specified but NOT used
# +ellps=WGS84
5748070.07 698.769


The result is not good enough. I expect something like that:
4409920 5748280.

Whats wrong here? I got the "towgs"-parameters from a another 
helmert-calculation i found in the internet which work in another 
program i have here and show the results i expected.

Can you tell me where the mistake is?

Thanks in advance.

Hochschule Harz
Projekt Mobiharz
Tel. 03943/626654
Email: hwehr at hs-harz.de

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