I love Google Maps and their API, and am using it extensively in my new web site OurAirports. However, there are two problems that keep coming up for using Google Maps with an aviation application:
- Google Maps uses a Mercator Projection, grossly distorting the northern and southern parts of the world, and cutting off the area near the poles so that a few of the Antarctic airports don’t show up on my maps at all. I can understand the reasons for their choice, with simple panning and tile paging and a rectangular area, but it can make things look pretty silly sometimes (such as Greenland and Africa appearing the same size).
Aviation charts mostly use a Lambert conformal conic projection, which ensures that distances are preserved (any two points the same distance apart on the chart are the same distance apart in the real world); however, by definition this projection can’t show more than half the world at once, and generally shows much less than that, so it wouldn’t work for something like Google Maps.
“…which ensures that distances are preserved (any two points the same distance apart on the chart are the same distance apart in the real world)”
I don’t think any projection from a curved surface to a flat plane can preserve distances. As I understand it, the Lambert conic conformal is just a better approximation to this than most.
Actually, there is an API to draw great circles. It was added in v2.84 of the Google Maps API:
Thanks for spotting that, Keith — I’m glad that Google has added great circles after all. Right now, the segment resolution is a bit too coarse (the great circles look pretty chunky), but I’m sure Google will deal with that soon.