Paul Tomblin wrote:
Bruce Rindahl wrote:
3. Is there any way to get the corners of a polygon or its bounding
box out
as separate points?
See the documentation on xmin, xmax, ymin, ymax
What documentation? In http://postgis.refractions.net/docs/ch06.html,
all I can find is "ST_xmin(box3d)". But experimentation shows I can
call 'xmin()' with a geometry, and 'st_xmin()' doesn't exist.
This is what I find so frustrating about the PostGIS documentation.
There are all these functions documented as "ST_*" but it turns out that
in order to use some of them, you actually have to leave off the "ST_"
part. This function is defined as requiring a box3d, but nothing I can
find in the docs actually comes out and says that if you have a method
that takes a box3d, you can call it with a geometry and it will use the
bounding box (ok, it does come out and say that for the && operator, but
it doesn't say it's true in general).
I'm really trying to read the manual before asking dumb questions, but
the manual is horrible.
Paul,
Just FYI, all the ST_* functions are very new and they automatic try to
use spatial index where the older ones do not and you had to explicitly
specify a clause with the && operator.
-Steve
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