# Talk:MGI / Balkans coordinate systems

Information about Bessel 1841 Ellipsoid is strange. It does not match neither of the three Bessel ellipsoids:

BESSEL 1841

Semi-Major Axis (Equatorial Radius)..[6377397.155] Flattening Inverse...................[299.15281535132334]

BESSEL 1841 NAMIBIA

Semi-Major Axis (Equatorial Radius)..[6377483.865] Flattening Inverse...................[299.152813272542]

BESSEL 1841 NORWAY

Semi-Major Axis (Equatorial Radius)..[6377492.0176] Flattening Inverse...................[299.152813272542]

Ellipsoid called Bessel 1841 in this article uses Semi-Major Axis of real Bessel 1841 Namibia, but flattening does not match neither Bessel ellipsoids.

For exYugoslavian maps, Bessel 1841 is indeed used, but one I specified above, not one specified in this article. However, shifting you specified, does not work with any of these ellipsoids. Error is too big (more that 350 m)

You should not use name Bessel 1841 for ellipsoid you use in article as that is surely not Bessel 1841 but it's variation.

## Wrong datum parameters

It is correct that Bessel 1841 elipsoid is used for this projection, but you quoted wrong elipsoid parameters: you used major axis from Bessel 1841 Namibia instead. Also, you mistyped flattern: 299 is correct, but you used all decimals from WGS84!

Correct parameters for Bessel 1841:

a = 6377397.155 1/f = 299.1528128

This elipsoid is really used for Balcans projection. In Serbia, we use this elipsoid with offset:

dx = 653 dy = -212 dz = 449

And that completes our version of Hermannskogel datum.

Nenad