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jenetics / jpx

JPX - Java GPX library
Apache License 2.0
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Make distance calculation more stable #134

Closed jenetics closed 3 years ago

jenetics commented 3 years ago

The current implementation for calculating the distance between two points contains code, where values are checked against zero. 

// Eq. 17 Careful! sin2sigma might be almost 0!
final double sinalpha = sin2sigma == 0.0
    ? 0.0
    : cosU1cosU2*sinlambda/sinsigma;

This kind of comparison isn't numerically stable. Replace this code with an epsilon check.

jenetics commented 3 years ago

Merged into r2.1.0 branch.