[Proj] New omerc approximations of Denmark System 34

[OvV_HN]

In reply to:

I have tried to implement the two Denmark System 34 (S34) projections for 
Jutland and Zealand.
I managed to approximate Kristensen's rotated Transverse Mercator 
approximations [1]
by using +proj=omerc with alpha and gamma
........
from:
Mikael Rittri


Reply:

This is an interesting approximation!
BTW, I haven't seen your reference [5], the online converter.
I believe it is:
http://valdemar.kms.dk/trf/

Furthermore I would like to add that I found at last the original 
polynomials at the Kort og Matrikelstyrelsen (KMS) site.
The KMS conversion tool source code has been put online and the System34 
conversion polynomials can be found in the file tcts_u.c, distributed from:
https://bitbucket.org/KMS/trlib/src/b02ad5890f03/TR_SRC/tcts_u.c
This url will undoubtedly change or disappear, in that case search for:
KMS / trlib
Geodetic transformation library from the National Survey and Cadastre, 
Denmark

You could examine the complete source code, but I noticed that CS-MAP from 
Autodesk has a neat implementation.
Look at:
http://svn.osgeo.org/metacrs/csmap/sandbox/RFC2/Source/CS_sys34.c
and you'll also need at least:
http://svn.osgeo.org/metacrs/csmap/sandbox/RFC2/Source/CSsys34KMS.c
plus the KMS file mentioned above.

Also Kai Borre has some sort of an approximation for System34.
See the files:
  s34j2utm.m
  s34s2utm.m
  s452utm.m
  utm2s34j.m
  utm2s34s.m
  utm2s45.m
in the folder:
http://kom.aau.dk/~borre/geodesy/


Hope this info can be of some help to users of DK System34.


Oscar van Vlijmen