Summary Box: Google’s maps go indoors

THE GREAT INDOORS: Google’s mobile mapping service now includes directions within stores, malls, airports and transit centers in the U.S. and Japan.

WHAT’S AVAILABLE: Only a small fraction of indoor locations for now. Google Inc. is hoping more owners and operators of shopping and transportation hubs will submit their indoor floor plans so they can be mapped.

THE DEAL FOR GOOGLE: This feature only works on smartphones and tablet computers running its Android software. It helps deepen people’s attachment to their Android phones so the company has more opportunities to sell ads on the go.