Difference between revisions of "Talk:Under The Hood"
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The best way to explain great circles is to first think of the old saying: "the shortest distance between two points is a straight line". For example, the shortest distance between the points (0,0) and (4,4) lies directly on the line y=x. To find distances in planer geometry it is as simple as finding a straight line which goes through those two points. But we have to remember that this is only true for Euclidean (or planer) geometry. | The best way to explain great circles is to first think of the old saying: "the shortest distance between two points is a straight line". For example, the shortest distance between the points (0,0) and (4,4) lies directly on the line y=x. To find distances in planer geometry it is as simple as finding a straight line which goes through those two points. But we have to remember that this is only true for Euclidean (or planer) geometry. | ||
| − | The Earth, however, is not a plane. It is a sphere. Spherical geometry is not the same as Euclidean geometry. A point-to-point distance is simply a line segment on a Euclidean graph, but when translated into spherical coordinates it is now an arc. (Case in point: the Euclidean distance formula is rather easy, whereas the spherical distance formula requires sines, cosines and the arctangent to compute). In the same manner as extending a line segment creates a line, extending an arc creates a circle. Navigational buffs out there call this circle: "the great circle". | + | The Earth, however, is not a plane. It is a sphere. Spherical geometry is not the same as Euclidean geometry. A point-to-point distance is simply a line segment on a Euclidean graph, but when translated into spherical coordinates it is now an arc. (Case in point: the Euclidean distance formula is rather easy, whereas the spherical distance formula requires sines, cosines and the arctangent to compute). In the same manner as extending a line segment creates a line, extending an arc creates a circle. Navigational buffs out there call this circle: "the great circle". Catch is, in order for the circle to be considered "great" it must bisect the globe into two identical hemispheres. |
If you ever see what the flight plan for transconinental airlines flying between London and New York is, it is an arc extending almost up to the Arctic Circle and then back down. That distance is shorter than flying on a direct line of latitude. Hope this helps. --[[User:Zombie|Zombie]] 10:31, 5 Nov 2005 (PST) | If you ever see what the flight plan for transconinental airlines flying between London and New York is, it is an arc extending almost up to the Arctic Circle and then back down. That distance is shorter than flying on a direct line of latitude. Hope this helps. --[[User:Zombie|Zombie]] 10:31, 5 Nov 2005 (PST) | ||
Revision as of 23:22, 6 November 2005
For saved game file discussion, NKF's analysis of LOC.DAT "20 binary rows, 50 entries" contains Geoscape tokens
- Nothing = 0
- UFO = 1
- X-Com Craft = 2
- X-Com Base = 3
- Alien Base = 4
- Waypoint = 7
--JellyfishGreen 06:05, 23 Aug 2005 (PDT)
JFG or anybody, what's the Great Circle Route?
enquiring minds want to know!
The best way to explain great circles is to first think of the old saying: "the shortest distance between two points is a straight line". For example, the shortest distance between the points (0,0) and (4,4) lies directly on the line y=x. To find distances in planer geometry it is as simple as finding a straight line which goes through those two points. But we have to remember that this is only true for Euclidean (or planer) geometry.
The Earth, however, is not a plane. It is a sphere. Spherical geometry is not the same as Euclidean geometry. A point-to-point distance is simply a line segment on a Euclidean graph, but when translated into spherical coordinates it is now an arc. (Case in point: the Euclidean distance formula is rather easy, whereas the spherical distance formula requires sines, cosines and the arctangent to compute). In the same manner as extending a line segment creates a line, extending an arc creates a circle. Navigational buffs out there call this circle: "the great circle". Catch is, in order for the circle to be considered "great" it must bisect the globe into two identical hemispheres.
If you ever see what the flight plan for transconinental airlines flying between London and New York is, it is an arc extending almost up to the Arctic Circle and then back down. That distance is shorter than flying on a direct line of latitude. Hope this helps. --Zombie 10:31, 5 Nov 2005 (PST)