[Mapserver-users] Drawing lines only once

[Norman Vine]

David Mitchell writes:
> 
> I want to effectively draw boundaries of countries. Currently I have 
> POLYGON data for each country and I want to draw the outlines for the 
> countries but I only want to draw outlines where two countries meet 
> once. 

AFAIK you will have to create new a line object from your polygon data 
outside of mapserver and have this as a separate 'line object'
in your mapserver data

The easiest way todo this make a list of all the line segments of 
the polygon object eliminating any duplicate entries.

Note that the a shared line segment will be in reverse ordering
i.e a shared segment from pt1 to pt2 in polygon will be ordered
pt2 to pt1 in it 'neighbor' polygon due to the consistant orientation 
required for polygon objects.

HTH

Norman