[postgis-users] Z and M coordinates seem inconsistent and barely supported

[Paul Ramsey]

AsBinary also strips out the higher dimensions in the interests of
spec compliance (old OGC spec)

select asewkt(geomfromewkb(asewkb('POINT(0 0 0 0)')));



On Thu, Jul 2, 2009 at 1:31 PM, Ben Harper<rogojin at gmail.com> wrote:
> Thanks - I see that EWKT works, but is there an equivalent mechanism for WKB?
>
> SELECT AsBinary(GeomFromEWKT('POINT(0 0 0 0)'));
>
> yield the exact same result as
>
> SELECT AsBinary(GeomFromEWKT('POINT(0 0)'));
>
>
>
> On Thu, Jul 2, 2009 at 5:56 PM, Paul Ramsey<pramsey at cleverelephant.ca> wrote:
>> select geomfromewkt('POINT(0 0 0 0)');
>>
>>
>> On Thu, Jul 2, 2009 at 8:51 AM, Ben Harper<rogojin at gmail.com> wrote:
>>> I'm struggling to create a geometry field in PostGIS that stores Z and
>>> M coordinates. Are these supported?
>>> Some issues:
>>> 1. I cannot create a ZM field. "Dimensionality must be 3 or less"
>>> 2. GeomFromText() doesn't recognize "POINT Z (0 0 0)"
>>> 3. GeomFromText() does parse (with a warning) "POINTM (0 0 0)", but it
>>> appears the DB isn't really storing the Z coordinate.
>>> 4. Using the C library interface, I can't get WKB geometry with Z to parse.
>>>
>>> Thanks,
>>> Ben
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