March 2017
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Great Circle Map Generator

For those of you that are interested in radio listening, particularly over long distances (AKA DXing) with even a moderately directional antenna, having a great circle map projection for  your location is a necessity.  Looking at a Mercator Projection, the normal “flat” map most are familiar with, one might come to the conclusion that due west from upstate NY lays the Washington/Oregon state boarder.  Appearances can be deceptive, bearing away at 270 degrees true (due west) from upstate NY is the California/Mexico boarder.

This is because the we live on a big sphere.  In this regard, the only place the the Mercator Projection is accurate is around the equator unless one is going due north (0 degrees) or due south (180 degrees).  The further north or south from the equator, the less accurate a flat map is.   Therefore, having a Great Circle map projection based on your location is handy for choosing the right azimuth to listen along.

As with many things, the internet provides the required tools to generate a great circle map for any location in the world.  The first thing needed is an accurate fix of your location.  This can be obtained via GPS, or, if you know how to look at a map and or satellite picture, itouchmap can be very useful.  Once you know where you are,  you can plug that information into this Great Circle Map Generator.

I saved the image as a bit map and use it as the wall paper on my computer.  That way, I just need to minimize any running programs and I can see what the correct azimuth is to any place in the world.  This is for upstate NY:

great circle projection

Great Circle Projection


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