How to use proportionoverlap to aggregate data from underlying geographies in Mapinfo Pro


Using a table of polygons ("polygon_overlap") and table of map objects containing data (pop_1980) it is desired to aggregate ("states"). The end result it to find the total pop_1980 for each polygon, based on the proportion of each state that each polygon covers.

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The query to run is as follows:

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This generates a table showing the sum of the pop_1980 data from each state that was covered by any portion of the polygons:
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1. It is required to type in "proportionoverlap"; it is not selectable from a drop-down in the SQL dialog.

2. This procedures assumes that the data is spread evenly throughout the underlying table holding the data. For large geographies, this is most likely NOT the case. (i.e. NY City has a greater population than upstate NY).

For smaller geographies, i.e. Blocks, etc., this procedure is much more accurate.


UPDATED:  April 21, 2017