Latitude/Longitude DMS to Decimal Converter

whammy · 11-13-2002, 12:15 AM

Converts Latitude and Longitude by DMS (Degrees, Minutes, Seconds) into decimal format. Please let me know if you find any bugs. I know that you can put up to 99 minutes and seconds in the fields, but that should still result in the correct decimal format regardless, as far as I have tested it.

Code:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
    "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" >
<head>
     <title>Latitude/Longitude DMS to Decimal Converter</title>
<script type="text/javascript">
<!--
/******************************************
DMS to Decimal Latitude/Longitude Converter
© 2002 Robert K. Davis
*******************************************/
function convert(D,M,S){
     var DD;
     D < 0 ? DD = roundOff(D + (M/-60) + (S/-3600),6) : DD = roundOff(D + (M/60) + (S/3600),6);
     return DD;
}
function roundOff(num,decimalplaces){
     var decimalfactor = Math.pow(10,decimalplaces);
     var roundedValue = Math.round(num*decimalfactor)/decimalfactor;
     return roundedValue;
}
function toDecimal(f){
     var LatDegrees = parseInt(f.LatDegrees.value);
     var LatMinutes = parseInt(f.LatMinutes.value);
     var LatSeconds = parseInt(f.LatSeconds.value);
     var LonDegrees = parseInt(f.LonDegrees.value);
     var LonMinutes = parseInt(f.LonMinutes.value);
     var LonSeconds = parseInt(f.LonSeconds.value);

     var LatDecimalDegrees = convert(LatDegrees,LatMinutes,LatSeconds);
     var LonDecimalDegrees = convert(LonDegrees,LonMinutes,LonSeconds);

     !isNaN(LatDecimalDegrees) && !(LatDecimalDegrees > 90) && !(LatDecimalDegrees < -90) ? f.LatDecimalDegrees.value = LatDecimalDegrees : f.LatDecimalDegrees.value = "";
     !isNaN(LonDecimalDegrees) && !(LonDecimalDegrees > 180) && !(LonDecimalDegrees < -180)  ? f.LonDecimalDegrees.value = LonDecimalDegrees : f.LonDecimalDegrees.value = "";
}
// -->
</script>
</head>
<body>
     <form id="conversionform" action="javascript://">
          <table border="0" cellspacing="0" cellpadding="0" width="200">
               <tr valign="top">
                    <td>Latitude:&nbsp;</td>
                    <td><input type="text" name="LatDegrees" size="3" value="" onblur="this.value=this.value.replace(/[^\d\-]/g,'')" />&deg;</td>
                    <td><input type="text" name="LatMinutes" size="3" value="" onblur="this.value=this.value.slice(0,2).replace(/\D/g,'')"/>'</td>
                    <td><input type="text" name="LatSeconds" size="3" value="" onblur="this.value=this.value.slice(0,2).replace(/\D/g,'')"/>&quot;</td>
               </tr>
               <tr valign="top">
                    <td>Longitude:&nbsp;</td>
                    <td><input type="text" name="LonDegrees" size="3" value="" onblur="this.value=this.value.replace(/[^\d\-]/g,'')"/>&deg;</td>
                    <td><input type="text" name="LonMinutes" size="3" value="" onblur="this.value=this.value.slice(0,2).replace(/\D/g,'')"/>'</td>
                    <td><input type="text" name="LonSeconds" size="3" value="" onblur="this.value=this.value.slice(0,2).replace(/\D/g,'')"/>&quot;</td>
               </tr>
               <tr valign="top">
                    <td colspan="4">&nbsp;</td>
               </tr>
               <tr valign="top">
                    <td colspan="4" align="center"><input type="button" value="Convert" onclick="toDecimal(this.form)" /></td>
               </tr>
               <tr valign="top">
                    <td colspan="4">&nbsp;</td>
               </tr>
               <tr valign="top">
                    <td>Latitude:&nbsp;</td><td colspan="3"><input type="text" name="LatDecimalDegrees" value="" /></td>
               </tr>
               <tr valign="top">
                    <td>Longitude:&nbsp;</td><td colspan="3"><input type="text" name="LonDecimalDegrees" value="" /></td>
               </tr>
          </table>
     </form>
</body>
</html>