Javascript: Convert DMS to DD

Hi Guys,

Here is a little object to convert decimal degrees (dd) to degrees minutes and seconds (dms) and the same in reverse. I've tried to optimise it to be as fast as possible to use with Google Maps when dragging over coordinates. Post your questions and comments and I'll try to assist you.

Next post I have an exciting script that allows you use a Google Sattelite Map interface to find your house and drag a marker over it to get the coordinates.

/* Written by Sparky Spider (http://sparkyspider.blogspot.com) */

function Coordinates() {
 
 // Properties

 this._latitude = 0;
 this._longitude = 0;
 
 this.LATITUDE = 0;
 this.LONGITUDE = 1;
 
 // Constuctor
 
 this.latitude = new DMSCalculator(this.LATITUDE, this);
 this.longitude = new DMSCalculator(this.LONGITUDE, this);
 
 // Methods
 
 this.setLatitude = function setLatitude(lat) {
  this._latitude = lat;
 };
 
 this.setLongitude = function setLongitude(lng) {
  this._longitude = lng;
 }  
 
 this.getLatitude = function getLatitude() {
  return this._latitude;
 }

 this.getLongitude = function getLongitude() {
  return this._longitude;
 }
 
 // SubClasses
     
 function DMSCalculator (coordSet, object) {
 
  var degrees = new Array (0, 0);
  var minutes = new Array (0, 0);
  var seconds = new Array (0, 0);
  var direction = new Array (' ', ' ');
  var lastValue = new Array (0, 0);
  var hundredths = new Array (0.0, 0.0);
  
  var calc = function calc(object) {
  
   var val = 0;
  
   if (coordSet == object.LATITUDE) {
    val = object._latitude;
   } else {
    val = object._longitude;
   }
   
   if (lastValue[coordSet] != val) {
    
    lastValue[coordSet] = val;
    
    if (val > 0) {
     direction[coordSet] = (coordSet == object.LATITUDE)?'N':'E';
    }
    else {
     direction[coordSet] = (coordSet == object.LATITUDE)?'S':'W';
    }
    val = Math.abs(val);
    degrees[coordSet] = parseInt (val);
    var leftover = (val - degrees[coordSet]) * 60;
    minutes[coordSet] = parseInt (leftover)
    leftover = (leftover - minutes[coordSet]) * 60;
    seconds[coordSet] = parseInt (leftover)
    hundredths[coordSet] = parseInt ((leftover - seconds[coordSet]) * 100);
    
   }
  }
     
  this.getDegrees = function getDegrees() {
   calc(object);
   return degrees[coordSet];
  }
  
  this.getMinutes = function getMinutes() {
   calc(object);
   return minutes[coordSet];     
  }
  
  this.getSeconds = function getSeconds() {
   calc(object);
   return seconds[coordSet];     
  }
   
  this.getDirection = function getDirection() {
   calc(object);
   return direction[coordSet];       
  }
  
  this.getHundredths = function getHundredths() {
   calc(object);
   return hundredths[coordSet];
  }
  
  this.getSecondsDecimal = function getSecondsDecimal() {
   calc(object);
   return seconds[coordSet] + (hundredths[coordSet] / 100);
  }
  
  this.setDMS = function setDMS (degrees, minutes, seconds, direction) {
   var val = degrees + (minutes / 60) + (seconds / 3600);
   if (direction == 'W' || direction == 'S') {
    val *=-1;
   }
   if (coordSet == object.LATITUDE) {
    object._latitude = val;
   }
   else {
    object._longitude = val;
   } // if
  } // this.setDMS
 } // DMSCalculator
} // Coordinates

It's really easy to use too. Here are 2 examples:

 function test() {
  var coords = new Coordinates();
  coords.longitude.setDMS(33, 46, 16.68, 'S');
  coords.latitude.setDMS(18, 44, 24.19, 'E');
  
  alert (coords.getLatitude() + ' ' + coords.getLongitude());
  
  coords.setLatitude (-33.7713);
  coords.setLongitude (18.7400527778);
  
  DMSStringLat = coords.latitude.getDegrees() + ' ' + coords.latitude.getMinutes() + ' ' + coords.latitude.getSecondsDecimal() + ' ' + coords.latitude.getDirection();
  DMSStringLng = coords.longitude.getDegrees() + ' ' + coords.longitude.getMinutes() + ' ' + coords.longitude.getSecondsDecimal() + ' ' + coords.longitude.getDirection();
  
  alert (DMSStringLat + ' ' + DMSStringLng);
 }

I'd love to hear if you have any improvements. Please post them here.