[postgis-users] Is there a standard direction for polylines?

Rick graham.rick at gmail.com
Tue Mar 10 15:20:37 PDT 2009

I'm fairly new to this.

I have a requirement to do calculations on runways in aerodrome maps.
I orient the runway centerlines west to east so that the low runway
number is at the start of the line.

I'm doing a similar, more complex normalization to the runway outline,
the first vector crosses the start of the centerline.  Whether they
are clockwise or ccw doesn't matter to me as long as it is always the
same.  Is there a standard insidedness for polygons which would
dictate a direction?


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