Thank you all for the reply. I found several of answers have been thrown out, but I just see them from the summary of yesterday's topic, not get those replies directly. Actually, I didn't get any mail from the list yet, perhaps, it's due that I just joined the list yesterday. So if you reply in this thread, please copy [email protected].
The provided methods (SE_IsMeasured() and SE_Is3D() zmflag()) do work on getting the dimension of a given geometry value. Probably, I didn't express myself well. What I really want to know is if there is some meta data to judge the type of the geometry column, not from sampling the data. For example, the POINTM can be used to know the column has 3dm points. But unfortunately, the corresponding GEOMETRYM type isn't provided for the mixed-type column in Postgis1.5. Can you tell me if there is some method to workaround the issue? -cheney On Wed, May 19, 2010 at 10:23 PM, 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 >> > >
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