[postgis-users] Create Voronoi Diagrams
gwilliamson39 at yahoo.com
Tue Mar 8 03:50:51 PST 2011
%3% is looking for anything for a "3" in it -- similar to *3* so this would find
every row for BOSTON with grades like .3, .03, 3.0, 1.3, 32, etc. that also have
a type of "pub" ...
As to why the "WHERE" clause?
Perhaps this example is not trying to create a Voroni diagram for their entire
database, but only for a relatively small number of rows.
Trying to create a Voroni diagram for a large data set will be slow and might
exceed memory or other system resources, so unless your database is small, I'd
try a subset of data, either limited by type or place name, or by a bounding
That said, I haven't used the referred function so I may be misleading with the
best of intentions. :-}
From: ΑΠΟΣΤΟΛΟΣ ΛΕΛΕΝΤΖΗΣ <lelentzisapostolos at gmail.com>
To: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
Sent: Tue, March 8, 2011 2:50:07 AM
Subject: [postgis-users] Create Voronoi Diagrams
For another time, i ask your help and your experience!!
Specifically, i want to create voronoi diagrams with postgis, and i found the
following intersting link
So, i have installed the pl/r language and i have run the voronoi function.
But, i don't understand what kind of my data i have to place, at the below line
WHERE town = ''BOSTON'' AND grades LIKE ''%3%'' AND type = ''PUB''
why the writer use a WHERE statement ??
what does mean the variable "%3%" ??
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