Armchair tourists traveling the globe via Google Earth can now watch YouTube  videos related to each destination they visit, Google announced Thursday.

A new YouTube layer in Google Earth's Featured Content folder allows users to zoom in on any location and view YouTube videos related to that place. For example, by zooming in on Maui, Hawaii, a user might see videos of surfing, snorkeling and exotic sea life; one checking out Chamonix-Mont Blanc, France, on the other hand, can watch breathtaking videos filmed at the highest points of the Alps.

"The integration of YouTube functionality into Google Earth offers a new way to experience destinations as seen through the eyes of YouTube users who have visited them, enabling people to watch, hear and feel what's happening in locations they may never have otherwise visited," Google said.

Local Context
To try out the new feature, users of the latest Google Earth client simply click on the Featured Content folder, and then on YouTube. Icons of the YouTube logo will then be visible on the globe. By mousing over those icons, users can see the titles of the linked videos. Clicking on them opens a pop-up bubble in which the videos can be viewed on Windows systems -- on Macintosh  and Linux, users will have to view the videos in their browsers instead.

"I think this is certainly interesting -- it enables people to put a lot more local context into whatever they're looking at," Rebecca Wettemann, vice president of research with Nucleus Research, told TechNewsWorld.

"There will be a lot of opportunities in historic sites to bring users in closer touch with what's there and where on the map it is," Wettemann added. "There's also another level of integration here, between Google Earth, video and the Web, that give us the ability to reach out on a much more global level."

Another Dimension
Users have already been able to add video to Google Maps for a while now, Greg Sterling, founder of Sterling Market Intelligence, told TechNewsWorld.

"What Google Earth has been doing for a long time is adding new content layers, including images and video, into Google Earth," he said. "Now they're doing it with their own property."

Such additional layers of information provide context and "are helpful and interesting," Sterling said. "They're another indication of the importance of video to the Internet , and they add a dimension of richness and other information not as readily conveyed through text."

Selection Criteria
The only question, Sterling noted, is what selection criteria -- if any -- Google uses to choose which of the many videos deriving from a particular place get linked into Google Earth.

In other words, since YouTube users uploading all kinds of videos have the option of geotagging them, or linking them with a particular location, will every video made in London be linked into that spot on Google Earth, for example? The result could be overwhelming at best, yet weeding some out could frustrate users expecting to see their videos on Google Earth, Sterling noted.

"That's a common problem that Google Earth has to solve," Brandon Badger, a product manager on the Google Earth team, told TechNewsWorld.

Increasing Breadth
The way it does so is by showing only a small selection of videos when users are viewing a location from the highest level, he explained. "When you're zoomed out, it might show only ten," he said. "Then, as you zoom in closer and closer, you'll see more and more until finally at the closest level you see all the ones Google Earth is aware of."

Included among those at the broadest level, then, could be videos without any direct geographical relevance.

The selection of which videos get displayed at the higher-level views is made automatically, and "it's certainly not perfect," Badger said. Criteria that get factored into that decision include the ratings people have given the videos on YouTube, as well as the number of views they received, he said.

"We're relying a lot on users," Badger admitted. "In a future version we might add a way for other users to flag a video if they don't think it belongs."

Indeed, "rating something in YouTube on the basis of popularity is different from rating it from the perspective of travel or education," Sterling noted.

Geotagging Incentive
Geotagging is also something not all YouTube users do when they upload their videos, he noted. "We're hoping the addition of this layer in Google Earth will provide some extra incentive," increasing the number of geotagged videos on the site, he said.

"We've spent countless hours browsing these videos, and we look forward to seeing what other geotagged videos are to come," wrote Amin Charaniya, a software engineer for Google Earth, on Google's Lat Long Blog for the Google Maps and Earth team.

Last month, Google launched Sky in Google Earth with images of about a hundred million stars and two hundred million galaxies.