Hmmm.
Ok so when I added the column, the paramters I passed where:
SELECT AddGeometryColumn('', 'point', 'coordinate', 600613, 'POINT', 0);
where 0 was the result of st_dimension, so should it be:
SELECT AddGeometryColumn('', 'point', 'coordinate', 600613, 'POINT', 2);
for a point?
Should it also be 2 for polygons -- given that these are the dimensions
of the same coordinate space?
Thanks!
Ed
[EMAIL PROTECTED] wrote:
The number of dimensions in this case is teh number of coordinates, if your point
has 2 (X & Y) then it is 2, not 0. If it is an XYZ point, then ndim = 3.
ndim does not reere to points @ 0, lines @ 1 & polygons @ 2, but the dimensions
of the coordinate space.
Cheers,
Brent Wood
--- On Mon, 7/28/08, Edward Bridges <[EMAIL PROTECTED]> wrote:
From: Edward Bridges <[EMAIL PROTECTED]>
Subject: [postgis-users] ndim vs. st_dimension and enforce_dims_coordinate
constraint
To: "PostGIS Users Discussion" <postgis-users@postgis.refractions.net>
Date: Monday, July 28, 2008, 7:30 AM
Hello,
I have a table with a geometry column which the
AddGeometryColumn stored
procedure has created a check constraint like so:
Check constraints:
"enforce_dims_coordinate" CHECK
(ndims(coordinate) = 0)
So, this uses the internal function "ndims" to
check the dimensionality
of the input coordinate.
However, I'm getting a discrepancy when inserting a
point into this
column since ndims and st_dimensions are returning
conflicting
(apparently) values:
rover=# select * from st_dimension(
ST_GeomFromText('POINT(1 1)'));
st_dimension
--------------
0
(1 row)
rover=# select * from ndims( ST_GeomFromText('POINT(1
1)'));
ndims
-------
2
(1 row)
It seems that the ndims function returns only 2, 3, or 4;
can someone
please explain why the differing values and how to insert
data into a
point-type geometry column (seems to work fine with
polygon) without
crossing the check constraint?
Thanks,
Ed
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