Name

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GEO_MID

Purpose

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This function returns the coordinates of the geographical point
midway between the two input points.

Category

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Geographical

Calling Sequence

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Result = GEO_MID( Longitude1, Latitude1, $
Longitude2, Latitude2 )

Inputs

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Longitude1: The scalar longitude, of type floating point, of
the first point. North is positive.
Latitude1: The scalar latitude, of type floating point, of the
first point. East is positive.
Longitude2: The scalar longitude, of type floating point, of
the second point(s). North is positive.
Latitude2: The scalar latitude, of type floating point, of
the second point(s). East is positive.

Outputs

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Result: Returns a vector of [ longitude, latitude ] coordinates
of the point midway between Points 1 and 2.

Uses

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CONSTANTS.pro

Procedure

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The function uses double precision floating point arithmetic
to calculate values.

Example

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Calculate the midpoint between Ottawa, ON (45.25N, 75.43W) and
Victoria, BC (48.25N, 123.22W).
results = geo_mid( -75.43, 45.25, -123.22, 48.25 )

Modification History

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  Written by: Daithi A. Stone (stoned@uvic.ca), 2000-07-24.
Modified: DAS, 2002-08-12 (complies with CONSTANTS.pro revision)