Thanks! On Tue, 15 Aug 2023 at 04:46, Thomas Knudsen <[email protected]> wrote:
> That definition definitely looks odd. The correct EPSG id for System 34 > Sjælland > is 10250 (and its companion for the western part of Denmark, "System 34 > Jylland" > is EPSG:10160). > > For historical reasons, those systems are utterly odd: They originated as > cadastral > systems, and the cadastre did not really care about the absolute > orientation of > the systems, hence ignoring (at that time, i.e. 1930-ish), existing > astro-geodetic > observations, to the effect that what was specified as a transverse > cylinder > projection actually ended up as oblique. > > Which also means, as noted by Mikael Rittri a decade ago on this mailing > list, that System 34 can be approximated at the metre level by an oblique > mercator > (proj=omerc). > > The reconstructions we recently submitted to the EPSG, are based on > transverse > mercator, but use grid based datum shifts to correct for the > mis-orientation and > network tensions. > > > Den tirs. 15. aug. 2023 kl. 00.18 skrev Javier Jimenez Shaw < > [email protected]>: > >> Hi >> >> I got this wkt, which projection "Transverse Mercator Sjaelland" is not >> supported by PROJ >> >> PROJCS["Danish_System_34_Sjaelland", GEOGCS["GCS_European 1950", >> DATUM["D_European 1950", >> SPHEROID["International_1924",6378388.000000,297.000000]], >> PRIMEM["Greenwich",0.000000], UNIT["Degree",0.017453292519943295]], >> PROJECTION["Transverse Mercator Sjaelland"], >> PARAMETER["Scale_Factor",0.999600], >> PARAMETER["Central_Meridian",9.000000], >> PARAMETER["False_Easting",500000.000000], UNIT["Meter",1.000000000000]] >> >> Seems to be something very Danish specific, and quite old. Do you know >> any equivalent wkt that may work in PROJ? There were some Danish grid files >> added recently for S34 >> >> Thanks >> Javier >> .___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__ >> _______________________________________________ >> PROJ mailing list >> [email protected] >> https://lists.osgeo.org/mailman/listinfo/proj >> >
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