So last week Google held a press event outlining several upcoming features and innovations in Google Maps, including the ability to use maps offline on Android (i.e., without a network connection), some pretty impressive 3D imagery, and shrinking the Street View camera so that it’ll fit in a backpack. The event was widely seen as a way to grab some of the limelight prior to Apple’s announcement of its own built-in maps for iOS, which came today (more on which in a moment).

None of the features are available yet, but there’s a certain tactical logic to emphasizing how much work goes on behind the scenes (it showcases the incumbent’s strengths) and pre-announcing products—none of which are available yet—when you’re about to lose customers to a competitor. (As Peter Batty wrote last week, “I suppose I’d be concerned too even if I was the size of Google, if I knew I was about to lose 250 million users or so when iOS 6 comes out, and had somebody with more money than the U.S. Treasury about to stomp into my market.”)

Maps in iOS 6 were announced as the last major item in today’s WWDC keynote. What’s interesting in the Google-vs.-Apple context is how much the new default app approaches feature parity with Google Maps on Android. Even though Apple’s Maps app circa iOS 1 through 5 used Google’s maps, it was, I believe, an Apple app. For whatever reason, it lacked features like turn-by-turn directions that could be found on Android (you could, of course, buy a third-party app with those features). Now it’s got them, and real-time traffic based on crowdsourced user data, good-looking 3D imagery, and Apple’s own map tiles. Some of those features will only be available on the iPhone 4S, iPad 2 and third-generation iPad, though.

Lots of initial speculation as to where Apple was getting its maps from. (You may recall that this was a concern of mine.) It looks like TomTom will be its primary map provider, though other sources appear to be used as well (9to5Mac, Engadget, The Verge). It makes sense that Apple would turn to an established map data provider (TomTom bought Tele Atlas some years ago), though this bucks the trend where companies try to own their own maps or use open map data.

One interesting thing that many people may have missed: in addition to mapping APIs, Apple is offering APIs to integrate transit data into the main map app (rather than using separate transit apps).

As for where this leaves Google on iOS, it’s generally thought that Google will have to offer its own Google Maps app. They didn’t say so explicitly last week, but that was before Apple’s announcement. I think a Google Maps app for iOS will be very interesting: will it have the same features as the Android version, or will some features be held back for competitive reasons?

Update, June 12: Don’t miss Peter Batty’s reaction to Apple’s announcement and his initial thoughts on playing around with the beta. He notes, among other things, that Apple (obviously) doesn’t have Street View. And to see how it all looks, watch Cult of Mac’s hands-on video.