[Proj] old german topo

[Clifford J Mugnier]

Dear Maciek,

It appears that you have a simple Transverse Mercator (TM).  The
Gauss-Kruger formulae are the exact same formulae used nowadays for the UTM
and many (not all) Transverse Mercator projections used world-wide.  Prof.
Carl Friederich Gauss developed it in the early 1800s and Col. Kruger (with
an umlaut) re-cast the equations into a form well-suited for tabular hand
computation.  Some pre-WWII large-scale topographic maps, such as yours,
were on the Deutches Herresgitter (Germany Army Grid) which was identical
to the UTM except that the scale factor at origin was unity (1.0).
According to the WWII-era Planhefts compiled by the Wehrmach (Army), some
of those were referenced to Ferro.  The DHG system was the "secret" system
that greased the skids for the highly effective Blitzkriegs that were
utilized to assault and capture the Sudenland, etc.

In addition to reprojecting that old TM to a Polish Grid, you will have to
contend with a change in geodetic datums.  The old German Topos were
referenced to Pottsdam Datum on the Bessel 1841 ellipsoid.  Poland
currently uses the "System 42" Datum on the Krassovsky 1940 ellipsoid.  If
that has changed, I'd appreciate receiving information on the new system,
such as EUREF(XX) and the geocentric transformation parameters from the old
to the new.

The best way to figure the datum shift parameters is to get coordinate
pairs of churches (from the topo map and from the Polish system you wish to
act as control), rather than road intersections.  Road alignments have a
tendency to wander a bit over the decades as additional lanes are added
while churches of course, will not move.

Also see my column on the Grids and Datums of Poland (PE&RS, September
2000) available from the "ASPRS" web site listed in my signature block.

Write to me directly if you have further questions.

Regards,

Clifford J. Mugnier
Chief of Geodesy and
Associate Director,
CENTER FOR GEOINFORMATICS
Department of Civil Engineering
LOUISIANA STATE UNIVERSITY
Baton Rouge, LA  70803
Voice and Facsimile:  (225) 578-8536
======================================================
http://www.ASPRS.org/resources.html
http://www.cee.lsu.edu/facultyStaff/mugnier/index.html
======================================================



Hello Everyone!

I've got few sheets of an old (before The Second World War) German topo map
which I want to register in it's coordinate system and reproject into a
system being used know in Poland. Unfortunately I don't know the projection
definition of this German topo in detail. I'm writing the proj list hoping
here I will find someone able to help me with this.

Here go some details I managed to find out about these maps:
- 1:25000
- were called Messtischblättermap
- the prime meridian intialy was Ferro, next Greenwich (since 1885)
- Bessel ellipsoid
- Gauss-Kruger projection (I don't speak German but that's what I
understood
from the map's label (as in the proj.png)

A small piece of the map, top-left corner, sheet called "4955 Ostritz", is
attached - only 7 KB (mostly erased to be preserve space). 10 KB both
pictures together, I hope that's not too much.

I would very apreciate any information and suggestions where to look for
it.

Maciek Sieczka
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