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org2pol

Location of north pole in rotated map

Syntax

pole = org2pol(origin)
pole = org2pol(origin,units)

Description

pole = org2pol(origin) returns the location of the North Pole in terms of the coordinate system after transformation based on the input origin. The origin is a three-element vector of the form [latitude longitude orientation], where latitude and longitude are the coordinates that the new center (origin) had in the untransformed system, and orientation is the azimuth of the true North Pole from the new origin point in the transformed system. The output pole is a three-element vector of the form [latitude longitude meridian], which gives the latitude and longitude point in terms of the original untransformed system of the new location of the true North Pole. The meridian is the longitude from the original system upon which the new system is centered.

pole = org2pol(origin,units) allows the specification of the angular units of the origin vector, where units is any valid angle unit. The default is 'degrees'.

When developing transverse or oblique projections, transformed coordinate systems are required. One way to define these systems is to establish the point at which, in terms of the original (untransformed) system, the (transformed) true North Pole will lie.

Examples

Perhaps you want to make (30ºN,0º) the new origin. Where does the North Pole end up in terms of the original coordinate system?

pole = org2pol([30 0 0])

pole =
   60.0000         0         0

This makes sense: pull a point 30º down to the origin, and the North Pole is pulled down 30º. A little less obvious example is the following:

pole = org2pol([5 40 30])

pole =
   59.6245   80.0750   40.0000

See Also

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