MapInfo Pro Developers User Group

AreaOverlap returns the actual area (where region objects overlap each other) expressed in specific units of measure, such as square miles, etc.

ProportionOverlap, however is a ratio that returns a value from 0, meaning "No Overlap" to 1, meaning the entire object is overlapping.

Please see this article that explains the difference.

The following link is no longer available. To access this information, copy the title found in the url into the search tool on the top nav bar, or try searching for key words in the post. https://li360.pitneybowes.com/s/article/ka1800000004Wt7AAE/Difference-between-AreaOverlap-and-ProportionOverlap

Very important to notice the difference :-)

I tend to recommend to users to use a combination of functions in stead of AreaOverlap: Area(Overlap(), "area units")

The benefit of doing so is that you can specify the area units and you can also use the more precise cartesian area calculation if you are working with projected data using the specific CartesianArea() function.

Peter, that is a very good point, much appreciated.