Stephen,
Apples, oranges, and peaches.
The ellipsoidal Transverse Mercator was first utilized for
a real project by Carl Freiderich Gauss in the early 19th
century. Kruger was one fellow (in Prussia) that re-cast
his equations in the late 1800's to early 1900's so that it
could be computed by mere mortals with the aid of
logarithms, his special book of projection tables, and a
lot of time. That was Kruger (with an umlaut over the
"u.")
After World War II, the U.S. Army Corps of Engineers cooked
up the UTM that is based on the Gauss-Kruger (with an
umlaut). There ARE other Transverse Mercator equations for
some other special countries.
The Russians came up with their version of UTM, but the
scale factor at origin was unity as compared with the UTM
that has an error of one part in 2500. Other than that,
the two systems (and the math) is identical. The Russian
system is identical to the Nazi "DHG." Boy, can you create
a bar-room argument based on who did it first! Best advice
I have is to duck! Don't spill your beer ...
Before the end of World War II, Professor Krassovsky came
up with his ellipsoid based on the vast collection of
Russian Triangulation Arcs that were predominately
north-south in their extents.
The classical horizontal geodetic datum used in the former
U.S.S.R. is the "SYSTEM 42," where the origin is at the
astronomical observatory at Pulkovo. The ellipsoid of
reference is the Krassovsky ellipsoid. That datum is a
specific system of latitudes and longitudes that is still
considered a military secret by the Commenwealth of
Independent States (C.I.S.). The Russians DO use the
Gauss-Kruger (with and umlaut) Transverse Mercator.
Playing games with projections (UTM and the Russia Belts)
will not cure your woes with data compatibility among the
former satellite countries of the former U.S.S.R. Although
the System 42 is a marvellous geodetic datum that is
remarkably consistent for the entire continent from Eastern
Europe to the Russian Far East, the existing topographic
maps of the former USSR may not ALL be referenced to System
42. Beware of making generalities, especially with respect
to datums. Changing the parameters of a Transverse
Mercator projection within a software package will not
accomplish much other than allow you to generate immense
amounts of garbage data with fantastic efficiency. You are
going to need to sit down and do a bit of reading and
study. Perhaps a LOT of study. Maybe not; maybe your I.Q
is over 300 and you read fast.
If you don't know what a datum is, or the differences in
different transformations from one country to another, I
suggest you look up my past columns in "Photogrammetric
Engineering and Remote Sensing." You can download some of
them from the society's web site at:
http://www.asprs.org/resources.html
(Look under the category of "Grids and Datums"). If the
stuff is of interest to you, consider joining the society
and getting a monthly subscription to the granddaddy of all
journals on the topic of "GIS." Besides which, you'll get
the marvellous benefit of reading my ruminations each month
on this sort of stuff. And the sarcasm is free!
(Lagniappe in New Orleans).
I have no idea what the ESRI current implementation of
geodetic transformations is like.
So, what does "AICP" mean?
Cliff
Clifford J. Mugnier ([EMAIL PROTECTED])
The Topographic Engineering Laboratory
Department of Civil and Environmental Engineering
UNIVERSITY OF NEW ORLEANS
New Orleans, Louisiana 70148
Voice and Facsimilie: (504) 280-7095
--------------------------------------------------------
---------------------------------------
On Tuesday, 03 August, 1999 6:12 PM, Stephen Kerlin
[SMTP:[EMAIL PROTECTED]] wrote:
> Can anyone tell me how I can convert GAUSS KRASOVSKII OR
> GAUSS KRUGER
> MAP PROJECTIONS in PC Arc/Info or Arc/Info for Window NT?
> I am doing a
> project on Eastern Europe. Some of my maps are in the
> Universal Transverse
> Mercator Grid. Currently, I have an opportunity to
> purchase Soviet Union
> military maps with the G-K
> projections. Can anyone tell me how I can match the two
> types?
>
> Stephen Kerlin, AICP
> [EMAIL PROTECTED]
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