ST_NDims() returns the number of dimensions, but that doesn't distinguish between XYM and XYZ. The ESRI compatibility functions SE_IsMeasured() and SE_Is3D() (hey, they are useful after all!) return the information you are looking for.
P On Wed, May 19, 2010 at 7:23 AM, 孙琦 <qsu...@gmail.com> wrote: > Can anyone throw some lights on the question? > > Thanks, > Cheney > > On Wed, May 19, 2010 at 6:27 PM, 孙琦 <qsu...@gmail.com> wrote: >> >> Hi experts, >> >> Do we have a way to resolve the third dimensionality of GEOMETRY data? As >> known, those single types(POINT, LINESTRING, POLYGON....) all have the >> corresponding XYM versions with suffix M. Thus, if we have >> three-dimensionality feature, we can discriminate its third dimensionality >> as Z or M by the returned geometry type. However, if the mixed-typed >> (GEOMETRY) is used, it seems that it's hard to resolve the 3rd >> dimensionality. By the Postgis 1.5.1 manual, no GEOMETRYM type is provided >> to fix the issue. So can someone tell me if there is another way to do the >> work? >> >> Thanks, >> Cheney > > > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users > > _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users