From WWDC 2010, the purpose of the cache is for offline use, and to minimize network calls. Since it's the same code on both iPhone, iPod Touches, and iPads, the WiFi part in particular is important, since not all the devices may have 3G data connections at all times. The example they gave at the presentation was an iPod touch user pulling out his device while at the conference and locating a nearby restaurant using the free WiFi there. By searching in an area, Apple also sends down the relevant WiFi access points in the area to feed into the cache. When the user leaves the conference center and drops off the data network, the Maps program can still show a pretty accurate location, allowing the person to navigate to the restaurant. If he takes any photos or video along the way, it's all geotagged too if the user enabled that feature.
For Android, (and likely every other phone with AGPS) the cache is there to minimize the times the phone has to go and ask over the data network to get the initial seed data for the real GPS. Apple took it a little father to also help out their GPS lacking devices.
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Makes sense. I think what they need to do is shorten the cache reuse duration, because they're currently (apparently) is no limit as to how long the cache is maintained. It was added with iOS 4, so it's a relatively new addition.
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From WWDC 2010, the purpose of the cache is for offline use, and to minimize network calls. Since it's the same code on both iPhone, iPod Touches, and iPads, the WiFi part in particular is important, since not all the devices may have 3G data connections at all times. The example they gave at the presentation was an iPod touch user pulling out his device while at the conference and locating a nearby restaurant using the free WiFi there. By searching in an area, Apple also sends down the relevant WiFi access points in the area to feed into the cache. When the user leaves the conference center and drops off the data network, the Maps program can still show a pretty accurate location, allowing the person to navigate to the restaurant. If he takes any photos or video along the way, it's all geotagged too if the user enabled that feature.
For Android, (and likely every other phone with AGPS) the cache is there to minimize the times the phone has to go and ask over the data network to get the initial seed data for the real GPS. Apple took it a little father to also help out their GPS lacking devices.
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Makes sense. I think what they need to do is shorten the cache reuse duration, because they're currently (apparently) is no limit as to how long the cache is maintained. It was added with iOS 4, so it's a relatively new addition.