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#!/usr/bin/env ruby -w
# encoding: UTF-8
#
# = Activity.rb -- Fit4Ruby - FIT file processing library for Ruby
#
# Copyright (c) 2015 by Chris Schlaeger <cs@taskjuggler.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
#
module Fit4Ruby
module GeoMath
# This method uses the ellipsoidal earth projected to a plane formula
# prescribed by the FCC in 47 CFR 73.208 for distances not exceeding 475
# km /295 miles.
# @param p1_lat Latitude of the first point in polar degrees
# @param p1_lon Longitude of the first point in polar degrees
# @param p2_lat Latitude of the second point in polar degrees
# @param p2_lon Longitude of the second point in polar degrees
# @return Distance in meters
def GeoMath.distance(p1_lat, p1_lon, p2_lat, p2_lon)
# Difference in latitude and longitude
delta_lat = p2_lat - p1_lat
delta_lon = p2_lon - p1_lon
# Mean latitude
mean_lat = (p1_lat + p2_lat) / 2
# kilometers per degree of latitude difference
k1 = 111.13209 - 0.56606 * cos(2 * mean_lat) +
0.00120 * cos(4 * mean_lat)
# kilometers per degree of longitude difference
k2 = 111.41513 * cos(mean_lat) -
0.09455 * cos(3 * mean_lat) +
0.00012 * cos(5 * mean_lat)
Math.sqrt(((k1 * delta_lat)) ** 2 + (k2 * delta_lon) ** 2) * 1000.0
end
def GeoMath.cos(deg)
Math.cos(deg_to_rad(deg))
end
def GeoMath.deg_to_rad(deg)
deg * Math::PI / 180
end
end
end
Version data entries
32 entries across 32 versions & 1 rubygems