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Difference between AreaOverlap() and ProportionOverlap()

UPDATED: April 20, 2017


Question:
What is the difference between AreaOverlap() and ProportionOverlap()?

Answer:
AreaOverlap() function:

Purpose

Returns the area resulting from the overlap of two closed objects.

Syntax

AreaOverlap ( object1, object2 ) 
object1 and object2 are closed objects.
** The order in which the objects are selected does not matter. The return value will always be the area of the overlap.**

Return Value

A Float value representing the area (in MapBasic's current area units) of the overlap of the two objects. 


ProportionOverlap() function:

Purpose

Returns a number that indicates what percentage of one object is covered by another object.

Syntax

ProportionOverlap ( object1, object2 )
object1 is the bottom object (not text or points), i.e. the object whose proportion of overlap is being calculated.
object2 is the top object (not text or points), i.e. the object that does the overlapping.
** The order in which the objects are listed is critical. If the order is switched, a different value will be returned.**

Return Value

A Float value equal to Area(Overlap(object1,object2) ) / Area(object1).
** The value that is returned is not the area of overlap, it is the percentage of area overlapped. To get the area of overlap, multiply the ProportionOverlap value by the Area of object1. **

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