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I have to move from a point A( lat, lng ) to point B( lat, lng1 ). The latitude of the both points is a constant. I know the distance between them ( in meters ), so i need the formula to find the longitude of point B.

  • How to find the longitude of point B ?
Yordan Yanakiev
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  • See "Destination point given distance and bearing from start point" on [this page at moveable-type.co.uk](http://www.movable-type.co.uk/scripts/latlong.html) – geocodezip Sep 23 '13 at 14:41
  • It is close to, but there is not explained completely, neither it is a solution for my current case. – Yordan Yanakiev Sep 24 '13 at 07:09

1 Answers1

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You have to add (or subtract, depending which point is on West side) the following: distance_in_meters/Earth_radius_in_meters/cos(lat)*360degree/2/pi

or, alternatively:

distance_in_meters/Earth_equator_length_in_meters/cos(lat)*360degree

This works because the radius of circle of 'slice of Earth' (more precisely, intersection of Earth and plane perpendicular to Earth's axis, passing through point A), is equal to radius of Earth * cos(lat) - simple trigonometry. Then you just use the proportions:

360 degrees - 2pi R cos(lat)

x degree - d meters

x=360d/2/pi/R/cos(lat)

This is all assuming you use degrees.

akrasuski1
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