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Calculating centroid location in MapInfo Pro

UPDATED: September 7, 2018


The calculation of a centroid has not changed in MapInfo and is the same now as it was in previous versions.

The name "centroid" was probably a poor term. The term that OGC uses is "representative point" - a point to be used for operations such as labeling that is guaranteed to be inside the region. That is what a MapInfo centroid is and has always been. It has nothing to do with a mathematical centroid, and never has had anything to do with a mathematical centroid.

For a region, the largest polygon in the region is selected if it is a multipolygon region, and then the center of the MBR is calculated.
The MBR is the Minimum Bounding Rectangle, defined here.

If that point is inside the region, then that is assigned to be the centroid. If that point is outside the region, then it is moved in a predetermined direction that will result in a point that lies inside the region.

There is currently no way to create a centroid outside of a region object.

From the OGC page:
The term given to the center of an area, region, or polygon. In the case of irregularly shaped polygons, the centroid is derived mathematically and is weighted to approximate a sort of `center of gravity.` Centroids are important in GIS because these discrete X-Y locations are often used to index or reference the polygon within which they are located. Sometimes attribute information is `attached,` `hung,` or `hooked` to the centroid location.
 

Environment Details

Products affected: MapInfo Pro™


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