If you have an older version of PostGIS, the zmflag() function also returns the information you need.
P 2010/5/19 Paul Ramsey <[email protected]>: > 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 <[email protected]> wrote: >> Can anyone throw some lights on the question? >> >> Thanks, >> Cheney >> >> On Wed, May 19, 2010 at 6:27 PM, 孙琦 <[email protected]> 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 >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
