sub acos { atan2( sqrt(1-$_[0]*$_[0]), $_[0] ) } sub asin { atan2( $_[0], sqrt(1-$_[0]*$_[0]) ) } my $pi= atan2(0,-1); my @c= ( 33.943603, -118.408189, 39.17965, -76.668824 ); my $lat1= $c[0]/180*$pi; my $lat2= $c[2]/180*$pi; my $dlong= ($c[1]-$c[3])/180*$pi; my $ang= acos( sin($lat1)*sin($lat2) + cos($lat1)*cos($lat2)*cos($dlong) ); my $max= $ang * 3_963.19059; my $min= $ang * 3_949.90257; printf "%.1f .. %.1f miles (%.2f range)\n", $min, $max, $max-$min; my $h1= sin(($lat1-$lat2)/2); my $h2= sin($dlong/2); $ang= 2*asin( sqrt( $h1*$h1 + cos($lat1)*cos($lat2)*$h2*$h2 ) ); $max= $ang * 3_963.19059; $min= $ang * 3_949.90257; printf "%.1f .. %.1f miles (%.2f range)\n", $min, $max, $max-$min; __END__ 2318.6 .. 2326.4 miles (7.80 range) 2318.6 .. 2326.4 miles (7.80 range)