Certain SQL databases (such as SQL Server, Oracle, DB2, MySQL, PostgreSQL) support a special data type called "Location". If a table has a location field (which contains information about a record's position - latitude and longitude), then you can perform "geography" searches. For example, you can find all records that are within x miles of a certain location, or all records that fall within an area marked by the latitude and longitude of 3 or more points. You can put a Google Map in the Search Part of the Grid to make specifying geography searches easy.
This video shows how you can put a Google Map into the Search Part, and how Alpha Anywhere automatically generates the Portable SQL to query the database. The video demonstrates both "location" and "radius" searches.