One of the most requested features since we launched ExploreMetro’s apps for iPhone, iPod touch and iPad is offline street maps. It’s really handy to have a metro map for Shanghai, Beijing, Guangzhou, Taipei, Singapore or Hong Kong in your pocket, but many travellers don’t have a 3G connection while travelling, so they’re not able to access the Google Maps we provide for each station.
How do I get offline street maps?
With version 5.0 of our apps, we’re introducing Offline Street Maps for the first time! Version 5.0 of our apps are currently in review by Apple. We expect them to be available in mid-June 2011. They’ll initially be available on iPhone and iPod touch. To access offline street maps, tap a station, tap “Street Map”, then choose “OSM” (this is the default if your internet connection is offline).
Why can’t you just use Google Maps offline?
Unfortunately Google Maps’ terms of service do not allow us to provide cached/offline maps. So, instead we’ve turned to Open Street Map.
What is Open Street Map?
“OpenStreetMap creates and provides free geographic data such as street maps to anyone who wants them. The project was started because most maps you think of as free actually have legal or technical restrictions on their use, holding back people from using them in creative, productive, or unexpected ways.” All the information on Open Street Map’s map of the world has been manually entered by volunteers. If you’re interested in helping out, check out Open Street Map’s wiki.
Won’t this make the app much larger, if you have to embed maps for every station?
We’ve tried to keep the filesize as small as possible. Only a small area around each station is included. The total size for all 241 Shanghai maps is just 6MB, for example.
The offline street maps are incomplete or wrong
The completeness and accuracy of Open Street Map’s data varies by location. For example, here’s our offline street map of People’s Square in Shanghai compared to the equivalent Google Map:
Here’s Bishan in Singapore. A few roads are missing.
The data in Guangzhou by contrast is very incomplete. Nearly all road names are missing.
Will the offline maps be updated?
Yes, every time the apps are updated we’ll pull the latest data from Open Street Map to generate new maps, so you’ll always have the most up-to-date map available. This is just the first iteration of offline maps, and we’re really keen to have your feedback about if you find them useful, or suggested improvements. Do get in touch.