As someone who takes a lot of pictures I've often thought it would be nice to have location data embedded in the images. That way, a few months or years down the line I can easily find out where I took the pictures. All too often I end up looking at pictures from news conferences or vacations from the past and trying to remember exactly where they were taken.

So I was quite excited when Sony announced last week the GPS-CS1, a portable GPS receiver and software combo that promises to make all this possible. Here's how it works: when it's switched on the unit records its location -- and by extension your location if you're carrying it with you -- every 15 seconds. The data can then be added to images later by matching the GPS location database with the time that the pictures were taken.

For this reason it's important to make sure the clock on the digital camera is correctly set. No setting is needed on the GPS device because the time is also transmitted on the satellite signal.

So much for the theory. How does this perform in the real world? The answer, I'm pleased to report, is remarkably well.

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The biggest problem I had with the system is that it kept losing the GPS signal, but I think this has more to do with Tokyo and its high buildings than anything to do with the GPS unit. Loss of the GPS signal doesn

One of my first questions for Sony regarding the device was whether it syncs well with non-Sony cameras. In theory that should be no problem since the GPS location data and JPEG metadata are standards. Sony said it will likely work but the company will only guarantee that it works with Sony cameras.

I tried it out with pictures taken on two other cameras, a Pentax Optio and Nikon D70, and had no problems. It should work on any digital camera that outputs JPEG images with EXIF 2.1 standard metadata.

That's a welcome change from so many gadgets that are designed to work with only the manufacturer's products. In fact, far from being proprietary, the GPS location data output by the device is a plain text file so it could easily end up being incorporated into other systems should there be an application.

If you have a Sony camera then an upgraded version of the company's Motion Picture Browser software will take the location data and link straight into Google Maps so you can quickly browse images and see a map or satellite image of the place where they were taken.

If you don't have a Sony camera then you'll have to find another way of using the data. The good news is that support for GPS location data is already spreading through Web-based photo sites such as Flickr and Smugmug.