definding projection and datum - Transverse Mercator bessel 1841

[hila]

hello all
i recived raster and vector filies with
projection:Transverse Mercator
datum: bessel 1841
i tried to work with the MAPINFOW.PRJ file but i'm doing somthing
wrong
can you please help me
how do i add this projection and datum to the mapinfo pro?


thank for your help

Hila

[David R Sherrod]

Hila,

If you don't see a reply soon from one of the projection experts on the list, you might consider resubmitting your question with some more information about the part of the world where your data apply and also the form of your projection-file line that you've experimented with.  Sometimes it helps if the MI-List can see what didn't work for you.  Bessel 1841 has been used in Europe, Africa, and Indonesia, and from what I can tell, the scale factors differ depending on the modification used.  A bit of googling might answer some of your questions about the parameters needed.

I'm not an expert with custom projections, but I'll share my limited understanding to stoke the fire here.

The projection line you'll add to your MAPINFO.prj file should have something along the format of this, for Transverse Mercator.

"Helpful text here Transverse Mercator Bessel 1841 for [country]", 8, [your complex datum conversion here], 7, [origin longitude], [origin latitude], [scale factor], [false easting], [false northing]

It all goes on one line, and you replace the bracketed text (and brackets) with your corresponding values.

A string of numbers will go in the [complex datum conversion] space.  For example, the Bessel conversion to WGS84 for Namibia would use the following comma-separated string placed between the 8 and the 7 in my sample line (I've used spaces in the next line to set off the conversion visually). The Namibia conversion is simple because it doesn't require rotation parameters. (I think that's correct.)
8,         999, 10, -384, 664, -48,            7

The integer 8 is the Projection Number (Transverse Mercator), and the integer 7 is the Units Number (meters), each of which is already in the sample line that I used for laying the groundwork.

If there are rotation or scale parameters within the needed conversion, then use a 9999 as your opening number.
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From:	hila <hil...@gmail.com>
To:	MapInfo-L <mapi...@googlegroups.com>
Date:	11/17/2009 01:15 AM
Subject:	[MI-L] definding projection and datum - Transverse Mercator bessel         1841

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