Here’s a photo that I took about 30 minutes into a recent flight from Phoenix to Chicago.

As you can see, these are a small group of lakes adjacent to forested land.

Knowing only the departure time (30 minutes), general direction of the flight (northeast from Phoenix) and approximate speed of the aircraft (about 500 knots), I would have a difficult or impossible task trying to determine the name and location of these lakes.

Here’s how I solved this problem.

Being somewhat of a gadget freak, I picked up a small GPS device to use as a photo accessory. When used, it continuously records your geographic coordinates. So as I’m flying, it tracks the flight path of the aircraft.

Since digital cameras have a built-in calendar and clock, when you take a photo, the date and time is recorded as part of the image data – its timestamp.

Using included software, the timestamps of the photos are matched to the timestamps of the GPS recordings to determine the geographic coordinates at which the photo was taken.

This same software, in conjunction with Google maps has me looking for a body of water 20 miles away. I found that this is Lake Cuerva – east of Santa Fe, New Mexico.

For the more technically oriented, here’s more details: the pilot tells me that the aircraft flying at 35,000 ft (7 miles high) above the earth. If I hold the camera at a 45 degree angle and take a photo, that landmark is 35,000 ft away from the point directly beneath the aircraft. For this picture I was holding the camera at a 60 degree angle so the lakes are about 20 miles away. [tanget of 60 degrees is .32; therefore the distance is 35,000 ft / .32 ~ 110,000 ft ~ 20 miles].

Here’s a final example. On a flight to Europe the aircraft was preparing to land in Brussels. As I was unfamiliar with the area, I relied on the GPS.

Using the above technique I was able to determine that this was the town of Regulaar, Belgium.