With all of the discussion of GML and KML one might lose sight of some of the many applications of GML that are outside the commercial and consumer domain – applications which nonetheless have a big impact on our daily lives. One of these is air travel. While the dust is far from settled, there is the distinct possibility of GML and WFS being used to update aeronautical databases. What are those? They are databases that contain current information on the state of the airspace through which airplanes including commercial, private and military must fly (or must not fly). Airspaces are defined by terrain – by commercial, private and defense facilities – by obstacles (cranes, tall buildings etc.) and so on. More than airspaces are involved as well – since we need also to describe the facilities themselves (e.g. an airport) from which aircraft takeoff, land, taxi etc. All of these things involve geographic information and relatively complex geographic information – furthermore it is a case where accuracy matters and where we cannot ignore the curvature of the earth. Most importantly, it is case where we must synchronize a large number of databases (those on the ground and those in aircraft) so that they all have a common picture of the world. It would not be good if pilots, avionics and ground systems had different views of the world. GML and WFS (Web Feature Service) can be used to maintain this virtual common picture of the world.
Maybe next time you board a plane – have a look for GML in the cockpit.