GIS::Distance::Cosine3pm

Spherical law of cosines distance calculations.

Overview

Although this formula is mathematically exact, it is unreliable for small distances. See GIS::Distance::MathTrig for related details.

A faster (XS) version of this formula is available as GIS::Distance::Fast::Cosine.

Normally this module is not used directly. Instead GIS::Distance is used which in turn interfaces with the various formula classes.

    a = sin(lat1) * sin(lat2)
    b = cos(lat1) * cos(lat2) * cos(lon2 - lon1)
    c = arccos(a + b)
    d = R * c

See "SUPPORT" in GIS::Distance.

2 releases since Debian 12 (Bookworm); the text changed 1 time.