[Proj] Belge 1972 / Belgian Lambert 72 (31370) - towgs84parameters
j.l.h.hartmann at uva.nl
Fri Jan 22 10:03:34 EST 2010
On 22-1-2010 15:40, Mikael Rittri wrote:
> Jan, you wrote
> > All my observations about the towgs parameters have been tested with
> real Belgian coordinates overlaid over Google.
> Fine. But if you did make an error when transcribing the newer
> transforms into Proj.4 syntax, and
> the error was just in the rotation angles, then the effect may be too
> small to notice.
> I mean, the angles describe a rotation, so there is presumably a fixed
> point in Belgium where
> the rotation has no effect. If your test points happened to be near
> the fixed point, the
> effect of the reversed angle signs could be very small.
> > As I said before, the EPSG database is not very systematical in the
> way it represents its formulas,
> > it just takes them from whatever source is available, untested AFAIK.
> Never use them without testing them with real world coordinates.
> I agree completely. But I am not yet convinced that you are right and
> EPSG wrong for the newer transforms,
> although that is certainly possible. Do you have some link to the
> offician Belgian documents?
As I said in a previous email:
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