Have you considered subtracting a buffer around the boundary of each
polygon from itself. Kind of similar to st_buffer with a negative
distance but a good bit more stable.
st_difference(geom,st_buffer(st_boundary(geom),100))) from mypolytable ;
st_buffer(geom,-X) will work until X gets large enough to start to get
collapsing geometries and then you will get
ERROR: getPoint2d_p: point offset out of range
C.
Randall, Eric wrote:
Hi all,
I'm trying to figure out how to explode a set of polygons to display them with
space between. In my case they are municipal boundary polys but could be
anything. So far the only approach I can think of is using translate such that:
select st_translate(st_translate(poly, -x(st_centroid(poly)),
-y(st_centroid(poly))),x(p2) + (x(p2)- x(p1)), y(p2) + (y(p2) - y(p1)))
from
(select st_centroid(st_collect(geom))as p1 from mypolytable) as s1,
(select st_centroid(geom) as p2, geom as poly from mypolytable) as s2
The problem with this is that small polys (Boroughs, etc) relative larger ones
often don't get their own space until a large enough multiplier is applied,
i.e. x(p2) + (x(p2)- x(p1))*5, y(p2) + (y(p2) - y(p1))*5 , but then there is
too much space around the larger polys.
Anyone have a suggestion or done this another way? Thanks.
think i'm gonna splode...,
Eric
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