On June 6, 2012, Google announced Offline Maps for Android devices. Wow, this sounds great until you actually use it. Like many people, I had the expectations I could ditch my Navigon and Co-Pilot satnav apps on my 7" Galaxy Tab 2. For those expecting to get a free satnav solution for the Asus Nexus 7 device will be in for a big surprise as well.
How it works? You can store offline maps by selecting a coverage area.
For actual usage, it only works as a pre-cache or a backup data source for your navigation route. If you have a route/navigation set, you can use it as a cache in the likely chance you may encounter dropped data connections while travelling. In theory, this works fine if you have a data connection like I do on my Galaxy Nexus.
If you use it on a WiFi only device like the Galaxy Tab 2 or Nexus 7, you will need to make your route beforehand while you are in the vicinity of a Wi-Fi hotspot.
Now for my complaints. It shouldn't be called offline maps. Rather, it should be billed as a backup cache for your navigation. Sure, you can scroll around the map but thats it. You can't do much else.
If you have a phone or 3g/4g tablet, is it still worth it to use? It depends. The base map is only covers a small area so routing a trip from say San Francisco to Los Angeles won't be supported in offline maps. Forget about over-seas usage unless you have data connectivity abroad to initiate a route. The largest size you can cache offline is about 70-80MB which covers a few counties in a major metropolitan area. What about dropped connections? The likelihood of this ever happening in the San Francisco Bay Area is close to zero. You may some some pennies by having the phone access the offline the maps instead of draining your monthly 3g/4g data allotment.
In short, companies like Tom Tom, Garmin, and others have little to worry about Google's offline maps. In short, Google simply increased the cache size to 70-80MB, Before June 6th, you could already pre-cached your route to a 10 mile radius.