[postgis-users] LinestringZ not valid

[Chris English]

select st_isvalid(a.p), st_isvalid(b.q) from
(select st_geomfromtext('LINESTRINGZ(0 0 0, 1 0 0)')as p) as a,
(select st_geomfromtext('LINESTRINGZ(0 0 0, 0.00000001 0 10000)') as q) as b;

st_isvalid (a.p)   st_isvalid(b.q)
     t                        t

LINESTRING(s) have an work obligation to go somewhere, even if a very small distance,
and .5D doesn't constitute enough of a dimension to have gone somewhere as strk points out.
Chris

> Date: Mon, 22 Oct 2012 09:40:46 -0700
> From: ps.tiara at yahoo.com
> To: postgis-users at postgis.refractions.net
> Subject: [postgis-users] LinestringZ not valid
> 
> Hello,
> 
> I've tried to make a linestring with z value as below
> 
> select st_isvalid(a.p), st_isvalid(b.q)
> from (select st_geomfromtext ('LINESTRING Z(0 0 0, 1 0 0)') as p) as a,
> (select st_geomfromtext('LINESTRING Z(0 0 0, 0 0 1)') as q) as b
> 
> the result shows that linestring from table b is not valid,,it's caused too
> few points..
> is it impossible to make linestring (0 0 0, 0 0 1) ? how to make it valid?
> 
> thanks..
> 
> --t
> 
> 
> 
> --
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