Google's Maps team introduced three new technologies on Wednesday: a feature to save offline maps in the Android Maps app, advanced 3-D models of entire cities in Google Earth, and a new Android-controlled "Street View Trekker" backpack for capturing Street View images where bikes, cars and planes can't go.

Let's start with the backpack, the most provocative of the three technologies introduced.

Street View Trekker ——————-

The Trekker is essentially a miniaturized version of all the gear Google packs into its Street View cars and tricycles, including a 15-lens camera that can shoot 46MP images. The Trekker, however, is controlled by an Android smartphone plugged into the pack, which is surprisingly lightweight given its size.

I tried it on for myself, and was impressed by how easy it was to move around with the Trekker on.

Google Engineering Director Luc Vincent takes the Street View Trekker backpack for a hike. Photo: Google

Luc Vincent, a Street View engineering director, recently took a Trekker with him on a ski trip in Tahoe, collecting images that could be used for Street View shots of the slopes. Of wearing the backpack while skiing, Vincent said, "It's really not so bad. You've got to be a bit careful obviously, but, hey, it works."

Not everyone, however, gets the idea: "A kid came up to me and said, 'Hey, why don't you use a GoPro camera instead," Vincent said.

Google says only a handful of the backpacks currently exist, and unlike the other products it demoed Wednesday, the Trekker isn't a consumer technology that anyone can try out for him or herself. The company plans on using the Trekkers to map out castles, ruins, hiking trails, and the Grand Canyon – places where wheeled vehicles and planes can't go.

Google Earth's New 3-D Maps —————————

Using an iPad, Peter Birch, a Google Earth product manager, demoed a coming Google Earth update that showed a 3-D model of San Francisco displaying every single building in the city, as well as plant life, statues and other landmarks, each with it own modeling. A view of AT&T Park, home of the San Francisco Giants, showed the ballpark and its stands, scoreboard and lighting system fully modeled.

Google Earth is set for an update that will add advanced 3-D models to cities such as San Francisco. Image: Google

Birch wouldn't say exactly when the advanced 3-D modeling was coming, but said it was coming to iOS, Android and desktop versions of Google Earth soon, and that major metropolitan areas would be the first to get the 3-D treatment.

"The goal is to model the world in 3-D," he said in the presentation. "What we're doing is we're using automated technology to extract 3-D from aerial images." The aerial images are shot by a fleet of contracted planes equipped with custom, Google-designed camera systems that take 45-degree angle shots in each of the cardinal directions, as well as straight down.

An automated process called stereo photogrammetry uses algorithms to create 3-D models from the overhead photos. Those models are then overlaid with other images, colors and textures to give the models a photo-realistic look.

"Every single building here is modeled and that's important because we're trying to create magic here," Birch said. "We're trying to create that illusion that you're flying over the city."

Previously, a few landmark buildings were modeled in Google Earth, but those buildings were few and far between. Birch showed a view of San Francisco as it currently looks in the software, and only City Hall and the Transamerica tower had 3-D models, while all in between was flat.

Birch said that Google hasn't yet decided which cities would get modeled first, but that the company hopes to have "communities of over 300 million people modeled by the end of the year."

The advancement of Google Earth's 3-D modeling capabilities will come to all Google Earth apps – desktop, Android and Apple iOS. Wednesday's demo could rightly be construed as a move to show Apple what it will be missing out on – and what it will have to compete with – if indeed Apple ditches Google Maps in the next version of iOS, as is widely believed to happen as early as next week at Apple's World Wide Developers Conference.

Offline Maps on Android ———————–

The ability to save maps for offline viewing might not be as exciting as 3-D models of entire cities, or the Trekker backpack, but this new Google Maps for Android feature might end up being the announced feature we all use the most.

Google is adding the ability to save offline maps in a coming update to its Android Maps app.

The Google Maps app for Android, not iOS, will receive an update in the coming weeks that will allow it to save maps so they can be accessed by users when they're unable to connect to the cloud. Anyone who has ever tried to use Google Maps without a Wi-Fi connection or wireless signal knows how fruitless it is to actually use the app. Of course, offline apps have to be saved ahead of time – so there will be some planning involved to make this useful.

Rita Chen, a Google Maps product manager, demoed the feature on a Motorola Android tablet, saving a map of London for offline use. It worked just as advertised.

Google said the feature isn't yet coming to the Maps app in Apple's iOS, which is currently powered by Google Maps. The question of Google and Apple's mapping future, or lack thereof, hung over the event the entire time. When Google took questions from the press, many reporters tried to get Google to confirm or deny that Apple was striking out on a mapping effort of its own.

Brian McClendon, a vice president of engineering who leads the Google Maps and Earth team, wasn't giving in to the pressure, however.

"I'm very proud of Google Maps services and they're available on all devices today and we'll continue to make them as widely available as possible," McClendon said. "We would like to get all services on all platforms."