[postgis-users] Establish versus of a line

[Andrea Peri]

Hi,

I have a table with a geometry LineString.
This Linestrings are a pseudo-copy of the boundaries of some polygon
geometries hosted in another table.

I say "pseudo-copy" because the geometry is identical but the versus can be
changed (respect to the polygons).

I need to fill a field of the linestrings table with the versus of the line.
The versus of the linestring if defined like this:
 "1" if starting from first vertex of the line and going forward last vertex
, the polygon is on the left,
 "0" if the polygon is on the rigth.

I like to fill this field with a sql insert, but I don't understand if there
really a method to understand the versus of the line respect to the
polygons.

Many thx,

Andrea Peri.




-- 
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Andrea Peri
. . . . . . . . .
qwerty àèìòù
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