[MetaCRS] gsb grids in Proj4js

[RICHARD Didier]

> Hello everyone,
>

Hi Juan Pedro,

> I'm new to the list and to Proj4js. I've managed to do 7 parameters
> transformations between ED50 and ETRS89 (specifically, between EPSG:23030
> (ED50 UTM30N) and EPSG:25830 (ETRS89 UTM30N) and works like a charm,
> congratulations to the Proj4js dev team. I was wondering if gsb grids
> datum
> shifting is already in the stable trunk. I've seen there is a ticket in
> TRAC regarding this but, not being completely familiar with TRAC and the
> development process, I don't know if this support is already in the stable
> trunk. I've seen also that a gsb.js file is added to the definitions.


I have not yet committed ticket 81 to truck for the moment. But, i can
write that it is used in production for our openlayers' based webapp.

> Would
> you please drop a hint on how this file is created from the original gsb
> file?
>

The structure of the gsb grid is detailled in the ticket: (CTABLE
based). I didnot convert my gsb to this format, but i am sure it can be
done via a PROJ4 dedicated app.

Regards,

Didier
> Besides, if the dev team consider it useful, I can provide the 23030 and
> 25830 EPSG.js definition files for the source trunk, with the
> transformation parameters applicable for the almost the entirety of the
> Iberian Peninsula (only the northwest (Galician sector) uses a different
> set of parameters).
>
> Thanks, and keep up with the great work!
>
> Regards,
> Juan Pedro Pérez Alcántara
> Technical Director
> jp.alcantara at geographica.gs <alberto.asuero at geographica.gs>
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-- 
RICHARD Didier - Chef du pôle technique du Géoportail
2/4, avenue Pasteur - 94165 Saint Mandé Cedex
Tél : +33 (0) 1 43 98 83 23