[Gdal-dev] Question about Gauss-Kruger projection

[Frank Warmerdam]

On 10/27/05, lky <moon_inwell at 163.com> wrote:
> Hello, everyone
>
> I'm a new learner of gdal that I find that gdal open source can't support the Gauss-Kruger projection.Some friends tell me that I can use UTM(Universal Transverse Mercator) to replace the Gauss-Kruger. But I am not sure of this.
>
> My questions are
>
> 1.How to use Gauss-Kruger projection by gdal open source?

Kunyang Li,

My understanding is that Gauss-Kruger is another name for
Transverse Mercator.   GDAL (and PROJ.4, etc) supports
Transverse Mercator just fine.

> 2.Can the UTM project replace Gauss-Kruger projection? If it can, which is the difference between them and which I should pay attention to in program?

UTM is a specialized transverse mercator.  That is, UTM "zones"
are essentially aliases for transverse mercator with particular
projection parameters.  The central meridian varies by zone.

I believe it would be safer to say you can use Transverse Mercator
for Gauss-Kruger.  Some Gauss-Kruger projections are zonal, and
*might* happen to match up exactly with UTM zones, but this is
by no means certain.   So pay close attention to the parameters
(central meridian, center latitude, scale, false easting and false northing).

Best regards,
--
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