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# What exactly is this website for?

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http://gc.kls2.com/I just don't understand it's purpose :(

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Any direct path between two points on a sphere (globe) will be shown differently depending on the type of map you look at, and the orientation of the map. A Great Circle is the shortest distance between two points on a sphere (globe). So a Great Circle Route between two cities, say New York and London, would actually be flown in a straight line, but when shown on a flat map MIGHT appear to be a curved route instead (depending on the orientation of the flat map).The link below explains the concept in more detail.http://en.wikipedia.org/wiki/Great_circleThe website you listed just allows you to determine a Great Circle Route between any two places on the Earth.FalconAF

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When calculating a flight path between two points on the Earth, the Earth's radius must be taken into consideration.Hence, we really don't fly in a straight line within a three dimensional space.

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When calculating a flight path between two points on the Earth, the Earth's radius must be taken into consideration.Hence, we really don't fly in a straight line within a three dimensional space.
OMG. Well...in that case, I guess we should also include calculations that take into consideration the relative orbits of the Earth around the Sun, the Sun around the center of the Galaxy, the Galaxy's relative motion in relation to the rest of the Galaxies in our immediate Galaxy Cluster, etc, etc.I meant a straight line depicted on a two-dimensional MAP, for crying out loud.PS - Chock...nice in-depth reply. Well done.FalconAF

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OMG. Well...in that case, I guess we should also include calculations that take into consideration the relative orbits of the Earth around the Sun, the Sun around the center of the Galaxy, the Galaxy's relative motion in relation to the rest of the Galaxies in our immediate Galaxy Cluster, etc, etc.I meant a straight line depicted on a two-dimensional MAP, for crying out loud.PS - Chock...nice in-depth reply. Well done.FalconAF
Now that this comes up, many people are aware that FSX gets... creative when generating some GC flightpaths on its own. Certainly older MSFS iterations have had problems with GC navigation. By plotting alongside a known GC route, you can fudge the numbers for your own flightplan and make a decent enough approximation for most flight sim purposes. Jeff Shyluk Senior Staff ReviewerAVSIM

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In maritime navigation, in the days before computers and widespread electronic navigation, it was necessary to develop standard methods of computing courses and distances so they could be incorporated in the form of tables or specialized slide-rules. These were referred to as "the sailings". Commonly used sailings were developed based on the mid-latitude method, the Mercator method, and the great circle method. Great circle sailings generally involve equations using secants and cosecants, and tables for these have been available in the past, such as H.O. 211.Aeronautical charts typically use the Lambert conformal projection, so that straight lines approximate great circles.scott s..

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I guess I'll add this to my list of reasons why I don't want to move from Florida to Canada.

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I guess I'll add this to my list of reasons why I don't want to move from Florida to Canada.
:( Uhhh, sorry, but a curious Canadian wants to know ... what's the relationship between Great Circle routes and not wanting to live in Canada?

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Thanks for such great feedback and information guys - much appreciated.

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:( Uhhh, sorry, but a curious Canadian wants to know ... what's the relationship between Great Circle routes and not wanting to live in Canada?
The farther north you go the more of a factor the great circle route becomes as the shortest distance between two points. At the equator it's not a factor.Thanks for asking.

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The farther north you go the more of a factor the great circle route becomes as the shortest distance between two points. At the equator it's not a factor.Thanks for asking.
Huh???? You wanna run that one by me again??? It makes no difference whatsoever "how far north you go" in determining the shortest distance between two points on the Earth's surface. The shortest distance on a sphere (globe) is a straight line drawn on the circumference of the sphere (globe) between the two points, regardless of where the starting and ending points are located. The distance (length) of the LINE SHOWN on a graphical image, like a map, will vary greatly depending on the frame of reference of the two-dimentional map. A Great Circle Route that exists totally either North or South of the equator, when shown on a Polar Projection map, will be shorter than one shown on a map using the equator as the reference line, but the actual distances of the ROUTE, when flown, will be exactly the same.If you use a flight planning program like FS Commander, display a GPS Direct flight plan in both the "regular" map mode and then the "Round World" map mode to understand the difference. In "Round World" mode, FS Commander will show the "frame of reference" for the flight plan centered ON the flight plan itself (the Great Circle Route), and the flight plan's "line" will always show as a straight line, not curved at all.FalconAF

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Huh???? You wanna run that one by me again??? It makes no difference whatsoever "how far north you go" in determining the shortest distance between two points on the Earth's surface. The shortest distance on a sphere (globe) is a straight line drawn on the circumference of the sphere (globe) between the two points, regardless of where the starting and ending points are located. The distance (length) of the LINE SHOWN on a graphical image, like a map, will vary greatly depending on the frame of reference of the two-dimentional map. A Great Circle Route that exists totally either North or South of the equator, when shown on a Polar Projection map, will be shorter than one shown on a map using the equator as the reference line, but the actual distances of the ROUTE, when flown, will be exactly the same.If you use a flight planning program like FS Commander, display a GPS Direct flight plan in both the "regular" map mode and then the "Round World" map mode to understand the difference. In "Round World" mode, FS Commander will show the "frame of reference" for the flight plan centered ON the flight plan itself (the Great Circle Route), and the flight plan's "line" will always show as a straight line, not curved at all.FalconAF
If I'm in Newfoundland and fly to a point directly west of me by flying directly west by compass, I am not flying the shortest distance between two points. If I'm in Ecuador and fly to a point directly east of me by flying directly east by compass, I am flying the shortest distance between two points. No?

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If I'm in Newfoundland and fly to a point directly west of me by flying directly west by compass, I am not flying the shortest distance between two points. If I'm in Ecuador and fly to a point directly east of me by flying directly east by compass, I am flying the shortest distance between two points. No?

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Anyway, it gets too cold in Canada. :(

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