How to Use Great Circle Mapper Like a Pro

Great Circle Mapper, also known as “GCMap” and available at gcmap.com, has been a beloved tool among dedicated aviation geeks for quite some time.

More recently, it has become even more valuable for Canadians with Aeroplan’s implementation of distance-based reward pricing. Your reward-booking game will benefit greatly from familiarizing yourself with this online mapping tool.

In this installment, we’ll go over all of the Great Circle Mapper techniques that you can use to plan itineraries, chart out distances, and generate all the pretty routing maps you see here on Prince of Travel.

1. Mapping a Flight

First, you’ll want to enter gcmap.com in your browser and pull up the Great Circle Mapper homepage. Here, you’ll find a rotating “Featured Map” that is usually pretty interesting to look at, but you’ll want to concentrate on the main input bar at the top, which is where the magic happens.

Let’s begin with the simple task of mapping a certain flight route and calculating the distance – to take one of the Aeroplan loyalty program’s sweet spots, let’s say Montreal–Lisbon–Casablanca.

You’d enter this in the form of IATA airport codes or city codes, separated by hyphens (“-“). So in our example, it’d be “YUL-LIS-CMN”, and press the “Map” button or the “Enter” key.

If you don’t know the exact airport code, you can also enter the city name, and then Great Circle Mapper will ask you to “fix” a specific airport by choosing from a list of airports that match your entry, before showing you the finished map.

However, it may be easier to simply Google “Casablanca Airport”, and you’ll find the airport code “CMN” pretty easily.

Either way, you’ll end up with the following output, which shows you a nice map of the routing, as well as the distances of each leg and the cumulative distance of the journey.

With this knowledge, you can look up that figure of 3,645 miles on Aeroplan’s “Between North America and Atlantic Zones” chart…

“0–4,000 miles” corresponds to 35,000 points in economy or 60,000 points in business class with a partner airline.

Knowing this, you can now search for flights on Aeroplan and check if you’re getting good value. With dynamic pricing on Air Canada flights, you’ll know that you’re getting a good deal if the result comes in near the lower end of the dynamic spectrum.

If it’s much…