AllSubway HD is an iPad app that collects more than 100 subway and mass transit maps from cities around the world. That’s about all that can be said about it: it’s essentially an image viewer, with no other features, and the maps are the official ones from the various transit agencies, which are available elsewhere. No information is provided about transit services. There isn’t even a full-screen mode in landscape. Calling it Spartan would be an understatement. There is not much here, in other words, to appeal either to mass transit enthusiasts or to world travellers; at 85.7 megabytes and 99 cents, it’s not worth the storage space or the dollar.