<?php

function DMStoDecimal($deg, $min, $sec, $nsew) {
  $frac = ($min * 60 + $sec) / 3600;
  $decimal = $deg + $frac;
  if($nsew == "W" || $nsew == "S") { return $decimal * -1; }
  else { return $decimal; }
}

echo DMStoDecimal(87, 43, 41, "S") . "\n";
// tulostaa -87.7280555556

?>