When MapInfo Pro is geocoding it checks to see how many occurrences of the target address exist. If there is more than one, MapInfo Pro must decide which source address to use. If the user's target table has a column with region data, MapInfo Pro can refine geocoding within a boundary.
For example, assume that you are geocoding a database of records in Cook county, Illinois. The address in the database reads 200 Washington St. Within the county of Cook, there are eight towns. Four of these towns have a Washington St. Three of the four have a 200 Washington St. MapInfo Pro must now place the target address in the appropriate town. MapInfo Pro uses region information to do this. MapInfo Pro now matches a region designation for the target address against the region designator for the source addresses.
When you originally set up your geocoding operation, you had an opportunity to specify a region (boundary) to use in refining your geocoding operation. This dialog box displays when you choose Refine Search with Table and using Boundary Name Column.
If you specified a postal code table you enter the postal code and MapInfo Pro returns possible matches.
You could use any one of several different region types, including county name, town name, and postal code. Since almost all addresses contain postal codes, this is the most reliable way to refine your search. When you set MapInfo Pro to use postal codes to refine its address matching, MapInfo Pro will match the postal code of the target address against the postal code of the various matching source addresses. When it finds the correct match, it is finished with the geocoding process. MapInfo Pro can now get coordinate information from the source table and use it to place a point object into the target table.
However, once MapInfo Pro has completed this process, many addresses may be unmatched. You can match each one of them individually by geocoding in interactive mode. However, if you are working with a large database, you want to do as little of this as possible. There are other ways of improving MapInfo Pro's geocoding performance.
In the Geocode Options dialog box, you can specify that MapInfo Pro automatically pick a different boundary, providing there is only one, from the one you specify (Use A Match Found In A Different Boundary). You might have had MapInfo Pro geocode addresses to Northtown. One particular address, "223 Locust Ct." is not in Northtown, but it is in Westville, and no place else. In this case, MapInfo Pro would geocode "223 Locust Ct." to Westville. However, if MapInfo Pro had found a "223 Locust Ct." in Westville and another one in Center Valley, it would not geocode the address to either town. It would leave "223 Locust Ct." ungeocoded.