[OSRS-PROJ] gauss-krueger/transverse mercator

[Gerald I. Evenden]

In some instances, I have heard that GK (Gauss_Kruger) only applied to
5 zones centered on 3E, 9E, 15E, ... ---European coverage.  Regarding
the German grid you mentioned, it seems strange to use 500,000m easting
when the zones are only 3 degrees wide, half the GK/UTM width.

Any reading where the easting exceed 500,000m is obviously seriously
in error and/or the wrong zone (CM) was specified.  Same if the easting
is negative.

Incidentally, are you capable of specifying the zone number to the Garmin?
Seems to me that would be required especially when you are on the seam
between zones and can use either.

As for southern latitudes and GK, I have never heard, but I would think
that 10,000,000m false northing would apply.  If it is labelled as a German
system, then southern latitudes don't apply so why bother with a false
northing.

A trouble with the Gauss-Kruger nomenclature is that it means two
different things:
1) a method of computing the transverse Mercator projection
2) a coordinate system identical to UTM except for zone numbering

>From your description of the "German" grid system, this is not
the same as GK.
__________________________________________________
Jerry Evenden and the Low Riders, Katie and  Daisy May
gevenden at capecod.net  http://www.capecod.net/~gevenden
----- Original Message -----
From: Andreas Lange <Andreas.Lange at Rhein-Main.de>
To: <osrs-proj at remotesensing.org>
Sent: Monday, June 12, 2000 7:43 AM
Subject: [OSRS-PROJ] gauss-krueger/transverse mercator


> Hi,
>
> i have a problem with the transverse mercator projection (Gauss-Kruger
> Projection) only indirectly connected to proj4.
>
> I am writing a program for data exchange with garmin gps receivers,
> which give the position always in lat/lon wgs84, even if the receiver
> itself displays position and waypoints in 'german grid' coordinates
> (transverse mercator projection). I know that german grid here for
> germany uses 3 degree wide meridian stripes (0d, 3d E, 6d E etc.), adds
> a false easting of 500000 and prefixes the zone (0, 1, 2, 3, etc).
>
> But what on the southern hemisphere? Is there a constant false northing
> of 10000 m added as with UTM? The receiver displays only "----", so that
> i assume it is not defined for southern hemisphere.
>
> What with western longitudes? What with two-digit zones?
>
> The receiver gives me the following readings:
> lat    lon     easting/northing
> 29.27N 10.5W   5436500/5815100 (??)
> 29.27N 10.5E   4354200/3240000 (ok)
> 29.27N 18.83E  5579200/1675000 (??)
> 29.27N 18.83W  5923300/9718000 (??)
> 85.44N 18.83E  5009100/0035000 (??)
> 85.44N 18.83W  5923000/9718000 (??)
>
> Are those values (??) only an internal overflow of the receiver?
>
> Thank you in advance for any hints,
>
> Andreas Lange
>
> --
> Andreas Lange, 65187 Wiesbaden, Germany, Tel. +49 611 807850
> Andreas.Lange at Rhein-Main.de, A.C.Lange at GMX.net

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