[postgis] newbie question about distance( )

[gispmpf]

forgive me for this newbie question about the distance() function:
i have two lines in the same table (roads)to see the distance between 
them the correct sintax is:
select distance(FirstPoint(road l1),FirstPoint (r l2) from road r, 
where road.id=1 and r.id=2;

is that correct?

Also there is any function with get the interccection between two 
lines?

Thanks
João 

Brenn Erik wrote:
> Yes you can. You can use the PostGIS StartPoint() function to find 
the
> starting point of each line. Then you can feed the start points to 
the
> distance() function.

Right - 

	distance(FirstPoint(l1), FirstPoint(l2) )

(there's also a LastPoint() function)

dave



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