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BCowper

704 post(s)
#20-Nov-08 12:50

What does the SQL Distance function measure between Point and Area objects? Is it the distance from nearest edge/node of an Area to a point or the centroid of an Area to a point?


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tjhb

2,384 post(s)
#20-Nov-08 13:03

The distance from the point to the nearest location* along the boundary of the area (or zero, if the point is inside the area). *Not necessarily a coordinate.

BCowper

704 post(s)
#20-Nov-08 13:31

I was working on a query to find Areas within 500ft of a Point and was undecided if I should use Distance or use Touches with a 500ft Buffer of the Point - now I know either will give the same result.

Thanks Tim.


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tjhb

2,384 post(s)
#20-Nov-08 13:35

Brian,

Buffer() often won't give the same result, because it draws a "circle" having 32 sides. (The same goes for EnclosingCircle(), where that applies.) Distance() doesn't have this limitation so it's better to standardise on that where possible.

BCowper

704 post(s)
#20-Nov-08 13:50

Good to know, thanks again.


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