A location is not a mere number or label. On a large scale, location information challenges application developers to work with the mathematics of movement around the not-quite-spherical surface of the Earth; on a small scale, it requires complex calculations of optimal routes based on frequent updates of rapidly changing conditions.
But the investment of that effort offers huge potential rewards for the developer who masters the mechanics and has creative ideas about what to do with the results. After all, how often does a developer get to be part of the process of figuring out the usefulness of a whole new type of data?
The tools that developers have used in any given period have revealed the data types they thought of as fundamental; the legacies of those tools betray developers lack of familiarity with data types outside their familiar space. For example, the first programmers computed almost solely with numbers. The clumsy FORMAT statement of the FORTRAN of that epoch is evidence that working with text wasnt a frequent need or a polished skill.
The next generation of programmers took for granted the convenience of "glass teletype" text output and keyboard input. But developers are still writing code that works around the clumsy conventions of that time—when even lowercase text was a luxury, and multiple sizes and styles of font were simply unheard of outside a typesetters shop.
Today, the new data type is location, and there are many things about the location data type that make it genuinely different from other data types that programmers have come to know and understand.
A location may take the form of an ordered pair of coordinates—such as values of a latitude and a longitude—but there are aspects of location data that make it unlike other familiar numeric or alphabetic character types. Calculating distance between two locations is not a simple matter of subtracting scalar values nor even computing vector differences: Its more like envisioning the path that a beam of light would follow through a medium with wildly varying speeds of transmission.
The "distance" between two points—measured on anything but an academic straight-line basis—is not a geometric question but a project management determination: Of what are usually multiple possible routes, which one presents the best expected travel time and the least dreadful worst-case scenario?
People perform surprisingly sophisticated route planning tasks all the time, and they quickly recognize a naive algorithm when they encounter one. An application that recommends a route between two points based purely on the apparent distance by road or other path, ignoring—for example—the difference between highway and back-road speeds or the relative traffic density of different times of day, will not engage and retain the user. The state of the art in this area is rising quickly.
Location-based applications are therefore fertile ground for exploring the potential of using a Web service interface to incorporate, for instance, current information on weather, construction disruptions or other dynamic forces from data feeds that would be expensive to duplicate.
Indeed, if the voluntary sharing of information and the collaborative development of content are the hallmarks of Web 2.0, then perhaps the next step of automating that sharing would justify the label of Web 3.0. As soon as one talks of sharing location data, though, especially anything with a real-time component representing the behavior or plans of any identifiable user, the issue of privacy quickly raises concerns.
At the third annual Where 2.0 conference this coming May in San Jose, Calif., participants will doubtless explore issues that have arisen at the two prior events, such as the ownership of a users location history, the proper balance between law enforcement needs and personal privacy expectations, and the division of roles and costs between private service providers and public infrastructures.
Developers who ignore the issues and opportunities of location awareness will wind up on the outside looking in.
Technology Editor Peter Coffee can be reached at firstname.lastname@example.org.