As the map wars heat up, Amazon seemingly refuses to be left out. The e-commerce giant is rumored to be acquiring a 3D-mapping start-up called UpNext.

Four high school friends who wanted to make better maps founded UpNext in 2007. UpNext offers a dynamic map with three modes from which to choose: Immerse, which uses a 3D touch interface; Explore, which allows you to immediately see what's around you and highlight places you want to go; and Navigate, which gives point-to-point directions for driving, public transit or walking.

Amazon has not officially announced the acquisition, but GigaOM reported it last week, and The Wall Street Journal is confirming the deal. Neither Amazon nor UpNext could immediately be reached for comment.

The Kindle Connection

Greg Sterling, principal analyst at Sterling Market Intelligence, said Amazon's move into mapping may play out in several ways, including online-to-offline e-commerce. However, he added, that remains to be seen.

"The most likely bet is that this acquisition and any related development efforts are directed at offering proprietary mapping and potentially navigation services on future Kindle devices, which may include a smartphone," Sterling told us.

"It's a very provocative move, regardless, and suggests that Amazon will make additional mapping acquisitions to speed time to market of a more complete mapping capability."

New Revenue Stream

UpNext offers a free app for the iPhone and Android devices. It maps the entire United States. More than 50 cities are rendered in 3D with 23 enhanced 3D cities that offer full textures and roadways.

Zacks Equity Research said the acquisition will open up a new revenue stream for Amazon, which does not have a mapping service of its own. Specifically, Zacks said the deal will help Amazon build its presence in the mapping business and compete against the likes of Apple and Google.

"Gradually, competition is building up in the mapping business," Zacks wrote in its blog. "Apple has been using Google Maps since the release of the first iPhone in 2007, but recently announced that it will replace Google Maps with its own in-house map service."

Apple's Yelp Integration

Meanwhile, there are also rumors that Apple is planning to integrate Yelp into its new maps application. Apple unveiled an all new Maps app with vector-based map elements as part of iOS 6 in June.

Rather than depending on Google Maps as a default, Apple's Map app will offer turn-by-turn navigation guides you to your destination with spoken directions. A "flyover" feature promises photo-realistic interactive 3D views. And real-time traffic information is also part of the mix.

Yelp ratings were mentioned during the launch, but rumors suggest a stronger tie. Yelp could not immediately be reached for comment, but its shares rose to $26.16 in trading on the New York Stock Exchange.