Friday, September 21, 2007

Location is not GPS

This entry is also posted at the Little Springs company blog. If you feel compelled to comment, I'd do it over there as its quite a bit better read.
Precision in LBS
I find two things about location based services these days to be annoying. First, that its new and can now be done due to the technology getting there, and second that its synonymous with GPS. Literally. “Use your GPS-enabled phone to...” This is annoying because location technology has been about for years. I (and others I work with) worked on this stuff in '99-'00. Back then, GPS was not yet in phones, but certainly was on the horizon. Instead, we used:
  • Cell
  • Sector
  • Triangulation
The phone knows some of this stuff, and the network can easily work out the rest. Precision is variable, and pretty large, but pretty reasonable when you are talking about a weather application, or pre-populating a list of cities to choose from, or pre-centering a map with a selection of local restaurants. Sector is at least 800 meter precision, and can be better. Triangulation can be under 100 meters. That's close enough to surmise you are on a particular city block. GPS can give accuracy down to a few feet, but it cannot always or reliably do this. Lots of things get in the way of getting high precision from a constellation of moving satellites when outdoors, not to mention in buildings or driving through cities with many underpasses. Suggesting additional precision, like in the photo above, can get you or your users into trouble. Other networks can present challenges, and opportunities. While WiFi (and WiMax when it comes out) will be more challenging, location can be solved and exploited in interesting ways. Bluetooth can determine relative proximity to known devices, but network awareness without pairing could be used to infer locale based on fixed systems (like mobile payment stations). So, to guide our design and development of location services, remember that:
  1. Every phone is location enabled. As long as its on a proprietary network, all this data is available for at least some location finding.
  2. All the available location technologies must be addressed when designing your application or service. Precision and accuracy must be understood by designers, and correctly exploited by the product.
  3. If you work for a carrier, exploiting the network like this should be a snap. If not, your devices or software may or may not be able to be talk to the phone enough, and you might need to negotiate with the carrier.
  4. As in many other areas of your customer's lives, privacy concerns will continue to rise. There are actual regulations around this, but you also need to look useful without acting creepy. No one wants their app to be the next “stalker-ware.”

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