Hi,
Any comments or advice appreciated...
I have a table (155m points) of circumpolar depth points.
>From this I want to use POstGIS to generate polygons based on depths.
There are about 700,000 points in the Ross Sea region, each has a depth (or
altitude) associated with it. The points are 1/2nm apart (GEBCO 2008 data)
I figure the following approach will work to generate reasonable polygons for
areas in the Ross Sea shallower than 550m:
select astext(geomunion(envelope(buffer(geom,1.0/230.0))))
from srtm_ant
where depth <0
and depth >-500
and geom && setsrid(geometryfromtext('POLYGON((155 -80,155
-60,200 -60,200 -80,155 -80))'),4326);
The && WKT coords define the Ross Sea region, 1/2nm is 1/120 degree so a buffer
of 1/230 degree should ensure the envelopes of the buffered points all overlap.
Does anyone have any suggestions/advice regarding this?
Better or faster approaches, etc.
Thanks,
Brent Wood
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