[postgis-users] Difference beetween ST_ClosestPoint and ST_Intersection

[aperi2007]

Il 11/01/2011 21:12, Paolo Cavallini ha scritto:
> Il giorno mar, 11/01/2011 alle 20.52 +0100, aperi2007 ha scritto:
>> Hi,
>>
>> I need to find the intersection point between two lines,
>> the first choice is ST_Intersection, but I notice even the
>> ST_ClosestPoint function.
>> \df+ st_intersection
>> in the case of two lines, the two results converge, but if you have two
>> polygons, you can see the difference.
>> All the best.

Hi Paolo,

Of course this is a difference.
ST_Intersection is surely more flexible, usable with every kind of geometry.

But my question is: "why ST_ClosestPoint exist ?"

The only explain I can suppose is that for linear archives it give some 
advantage (more speed ?)

This is the question :)

Andrea.