The Blue Marble Mapper takes the 3-letter airport codes of two airports (ie, LHR for London Heathrow and LAX for Los Angeles), draws a map showing the two locations, and with the Great Circle route between the two points and details of the distance embedded into the graphic.

About The Maps
The base maps used are NASA's Blue Marble images; a fantastic view of the Earth using high resolution photography. As a trade off between speed and quality over short distances, a resolution of 3750x2250 is used for the original map. The map is cropped and scaled depending on the position of the two points given. Using the Great Circle formulae, a curve is plotted on the map (which is also scaled to the size of the map). Where the starting and ending points are further away than 180 degrees (half the distance around the globe), it's assumed that the shortest distance is 'around the back', so a different version of the base map is used. If the map fails for any reason (ie, the airport code given isn't in the database), the query is automatically passed over to The Great Circle Map to see if that can map it.