Points and lines layers provide two different ways to specify spatial locations for the data:
As a pair of expressions that evaluate to a longitude/latitude pair at run time. Typically these would directly reference corresponding data fields (longitude and latitude) stored in the data source.
As a MapLocation, an expression (or a list of expressions) that evaluates to a string that can be used to retrieve the corresponding spatial location using an external online service (Google Maps). If the specified MapLocation contains semicolons, it is treated as a list of semicolon-delimited expressions, each of which is evaluated separately and then combined to use as the query. A typical MapLocation could look like this:
"Address;City;PostalCode;Country"
which would fetch Address, City, PostalCode, and Country fields from the data source and then combine them to query the external service.
Note that using MapLocation may be very time consuming due to Internet access. Hence by default the retrieved spatial data is stored in a local disk file. The path to that file is specified by the Map.GeoCachePath property. By default the file's name is "geocache.xml", and it is stored in the same directory as the report definition. Disabling geocaching is not recommended.