Product Reviews

Google Earth has been making jaws drop for over a year, but now it's finally come out of beta - and it's better than ever. At its simplest, Google Earth can be thought of as just stitched-together satellite photos combined with Google's expertise at search technology. But it won't take long before you start to feel its true power.

The basic features of Google Earth are only a free download away. The client is about 11MB and needs to be installed locally; this isn't a web-browser-based application, at least not yet. The 3D features need a fairly modern graphics card, but nothing made within the last three years should have any problems. However, you'll need to choose either DirectX or OpenGL rendering; on our particular test system the OpenGL renderer was far more stable than DirectX.

Fire up the client and you're initially presented with a view of the planet from an altitude of around 4,000 miles, centred - unsurprisingly - on North America. You can soon fix that though, and this is where the amazing part starts. All you need to do is enter a UK postcode or place name - you don't necessarily even have to tell the client that it's in the UK - and hit Enter. Your view will immediately and smoothly fly across the world, zooming in and resolving more detail as it zooms, and end up hovering about 4,000ft above the postcode or place you entered.

It doesn't end there, though. In the more populated areas of the country, you can zoom in even further; the level of detail in some areas really is astonishing. As you zoom, the image data changes from satellite-based photography to aerial photographs taken from aircraft. If you're in a well-covered metropolitan region, the view is good enough to resolve individual cars, buses and even people - enter Buckingham Palace into the search box, for instance, and the crowds milling around the palace are clearly visible. If you're in a rural area, though, only satellite data is likely to be available, with a resolution often not exceeding three metres per pixel.

With Google being what it is - a data company - mere aerial photography is just the beginning. In a pane to the left of the interface is a list showing a raft of different layers of data you can overlay on top of the current view. Many are currently only of much use in US regions; our stateside cousins can enjoy 3D representations of buildings in 38 cities, but the feature isn't available anywhere else. Similarly, activating the 'terrain' layer in the US overlays terrain elevation data; tilting the 3D view then gives you a true 3D representation of the landscape instead of a geometrically perfect globe with a flat texture overlaid on top of it. Terrain data is available for the UK, but is limited.

In addition to the officially sanctioned Google-supplied data layers, you can also activate the Google Earth Community layers. The Community is the equivalent of a geographically linked web forum and works in concert with the client-side placemark feature. A placemark can be a single point with a text description, a web link or even an image overlaid on the standard Google Earth image data. Individual placemarks

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can be uploaded to the Google Earth Community by anyone, with some restrictions on length and content. Groups of themed placemarks can be uploaded too. As you might expect, the Community placemarks consist of an interesting hotch-potch of stuff, some useful, some less so. There's a complete set of marks for UK National Trust properties, for example.

The best Google-supplied layer that's fully functional in the UK is the roads layer. Although surprisingly comprehensive, it's not up to road atlas or A to Z standards: we saw numerous instances of small side streets being marked and labelled with the correct name, when larger roads nearby were either not marked at all or not labelled.

Elsewhere, the Local Search box theoretically allows you to find facilities, such as restaurants, based around your current location on the map. We found it patchy though; for example, it failed to come up with most of the restaurants in the area local to PC Pro's offices.

The Directions feature is better. Again, we found it patchy, sometimes failing to come up with anything, but when it works, it works brilliantly. Enter two locations and it will calculate the route between them. This is, of course, exactly what several online services such as theaa.co.uk already do. What they don't do is overlay the route with waypoints (such as 'turn left at The Avenue') marked on a scrollable, flyable aerial view, which is better than any normal map for getting an idea of what a journey entails. It's very generalised, though, coming up with a route but not necessarily the route you'd want; there's no ability to customise your preference for, say, cycling as opposed to driving and it doesn't know about things like railway stations; there's a specific layer dedicated to railway routes, but again, clicking on it currently only has any effect if you're viewing a region in the US.

For a $20 fee (about £12) you can upgrade to Google Earth Plus. The immediate benefit of this is faster network access, allowing much quicker image-data updates as you zoom in on a particular feature. The second benefit is integration with handheld GPS devices, although it's not as integrated as it might be. There's only the choice of downloading data from the GPS unit, not vice versa. A simple dialog box allows you to configure the client for Magellan or Garmin units, and pulls all of the data from the unit. You can then overlay the data, with your named waypoints, plus both tracks (ground you've actually covered in the real world) and routes (paths that have been programmed into the GPS in order to follow) overlaid on the map. It's fun to see where you've been, but very annoying that you can't upload routes calculated by the Directions feature to a GPS. It's also not currently possible to overlay your position on the map in real-time.

Bear in mind that none of the GPS import features are new; most mapping applications, such as Memory-Map, support the download and overlay of tracks, routes and waypoints and, more importantly, the upload of routes you've plotted. And of course, navigation software such as TomTom gives you real-time positional information.

There's no denying that Google Earth really is a minor miracle, truly harnessing the power of modern computers and high-bandwidth connections. At the moment, though, it's not actually very useful for UK residents. But the thing about it is, you know it's only going to get better. The Google Maps system (http://maps.google.com) is already being used to integrate geographical data from hundreds of sources and lots of effort is being made to bring that to Google Earth. This is an application with the potential to be the most important development on the Internet since the Internet itself.