From geo-location to "I'm on the bus". Communicating location is all about context
Where are you? Analysis of requirements for location
Because of a super secret project at work, I have been analysing requirements for location. Specifically, how do people answer the question: Where are you?
I expect Plato had something to say about the difference between taxonomy and understanding. I choose to ignore whatever it was and have analysed by classifying the types of location description we can give.
First off, and a warmish topic of the moment, co-ordinates.
Co-ordinates
Co-ordinates, also known as longitude and latitude, can be obtained by geo-location or in some other way. Chomsky should love them because co-ordinates require no context to be understood. Also, they are precise and unambiguous. So this seems like it should be the best way to state your location. Predictably though, there are issues with co-ordinates.
First, co-ordinates only address the physical aspect of location. More on that story later.
Second, because a co-ordinate location requires no context, and no familiarity with the located individual, there is a privacy risk. Anybody who can get hold of your co-ordinates can also get hold of you.
Third, and this might just be my experience, co-ordinates are not supported where they need to be. Some scenarios…
Scenario one
We’re trying to meet up right now and are both outside on the street.
So far as I can tell, unless we have both already signed up to a service like Latitude, and agreed that we want to share our locations with each other for ever, we cannot find out where we both are at this moment. Hardly a “set-up lite” solution is it? And it could be so much easier:
Step one: Your mobile device enables you to send your current location by SMS
Step two: My device receives the location SMS, and displays the received location, and its own location, on a map that is zoomed to the rectangle defined by the two points.
Step three. There is no step three. There was no set-up either, other than exchanging our mobile phone numbers.
Scenario two
I’m at my desk, planning how to get to your office. I have your postal address, and I know where I am.
Hmm, the address book in which I store contact details can handle postal addresses, but cannot store longitude and latitude co-ordinates.
Ah, my mobile device can only get my location when I’m outdoors.
Oh dear, I’m stymied. I have to copy and paste postal locations into a mapping utility like Google Maps.
Scenario three, counter example
On a recent holiday in Umbria, I noticed a tendency for tourist brochures to include the co-ordinates for the attraction that they promote. Given the local infrastructure, it would be pretty hopeless trying to give directions in prose, which would also require translation. So they enable you to use your car’s GPS. (I’m assuming you can punch co-ordinates into a GPS; a usability guru might have decided that would be “far too technical” for users to understand.)
That’s co-ordinates, the ultimate low-context statement of location. At the high-context end of the scale are locations like “at home”, “at the gym”, or “on holiday”. I call these evocative locations.
Evocative location
This type of location is not useful to me, the located individual, but it might be useful to you, the person who is trying to locate me. If I’m on holiday, you wouldn’t call me about a routine work matter. If I’m at the pub you might call me to see if you can come too.
Now, knowing my co-ordinates might enable you to work out something like an evocative location. For example, if you map my last known co-ordinates and find that they were within 5 metres of a pub door, you know I’m probably “at the pub”. Similarly, if you know where I live, and my current co-ordinates are within 10 metres of it, you might conclude that I am “at home” although I might be “on holiday” and getting on with some DIY.
That mobile classic “I’m on the bus”, generally shouted from the upper deck, fits here. At only four words, this is an economical way to convey location. The other party knows what kind of communication can now take place; they have an idea of where you are and where you will be in the immediate future, and they have a mental picture of your environment.
Back at the low-context end of the scale, nearer to co-ordinates than evocation, is postal address.
Postal address
Exchange of postal addresses is widely supported; they can be included in a contact record and sent by Bluetooth, SMS, e-mail etc.
They can be used in that hardcopy delivery service the old folks call “letters”. It’s also where Royal Mail will drop the slip that tells you to go to the sorting office so you can collect the stuff you bought on-line.
Postal addresses have stood the test of time, so far.
I’m trying to think of a non-postal scenario where I would prefer a postal address to co-ordinates and I can’t. But until co-ordinates are supported everywhere that I need them to be, postal address remains the best context-free location.
On the high-low context scale next to postal addresses are locations like: Edinburgh, Bermuda, Africa, Old Street. These are descriptive without being evocative.
Descriptive location
Like an evocative location, a descriptive location is more useful for you than for me. If I’m in Africa all week, there’s no point inviting me to a meeting in Bermuda this evening. Note that, for the purposes of the query “can you attend a meeting in Bermuda this evening” there is no need for a more specific location than Africa in the answer.
If you know the location of my London office, i.e. if you have a particular context, then when I give my location as London, you probably know exactly where I am. Somebody without that background, who gained access to my location as “London”, would not be able to locate me.
So this is a more private way to give location than postal address, but carrying a different kind of information than evocative location.
Conclusion
I thought of four types of location and ranked them as follows:
On to the question of requirements, which is my job…
Support for co-ordinates is generally required. I’d like to see them in a lot more applications, please.
Postal addresses must remain supported until user interfaces develop proper handling of co-ordinates.
Descriptive locations will give way to co-ordinates, I believe. In user interface terms, the choice will be between typing “Hackney” and clicking Send my geo-location now. People will pick to click, not type.
Evocative locations will, I hope, always be required. Where am I? I’m at my desk.
Would you have got more information out of my co-ordinates or postal address?
Copyright © Jim Hawkins, 2009



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