[postgis-users] Buggy transform() function in 1.0RC1 ?

RIBOT, Nicolas nicolas.ribot at astrium.eads.net
Wed Feb 2 09:50:46 PST 2005


Transform() is not buggy.

To follow my previous post, and thanks to Michael Michaud that noticed the
differences, the spatial_ref_sys.sql provided with postgis 1.0 RC is not the
same as the one provided with the previous Postgis versions, at least for
french projections.
Namely, for SRID=27582, the proj4 parameters in postgis 0.8:

+proj=lcc
+lat_1=46.8
+lat_0=46.8
+lon_0=2.337229166666667
+k_0=0.99987742
+x_0=600000
+y_0=2200000
+a=6378249.2
+b=6356514.999904194
+pm=2.337229166666667
+units=m

and in postgis 1.0RC:

+proj=lcc
+lat_1=46.8
+lat_0=46.8
+lon_0=-2.33722917
+k_0=0.99987742
+x_0=600000
+y_0=2200000
+a=6378249.2
+b=6356515
+towgs84=-168,-60,320,0,0,0,0
+pm=paris
+units=m
+no_defs

the sign of the longitude of origin is not the same, the value of the prime
meridian is also different.

Can we fear other projection systems to be inaccurate ?
Why the values of these well-know systems have changed between versions ?

Thanx
Nicolas Ribot
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