Latitude-Longitude Converter

Joe Ho Nov 11, 2005

Convert latitude and longitude from degree decimal to degree, minutes, and seconds and vice versa. This script will also find the farthest point from the point entered, as well as the distance.

The JavaScript Source: Math Related: Latitude-Longitude Converter

Simply click inside the window below, use your cursor to highlight the script, and copy (type Control-c or Apple-c) the script into a new file in your text editor (such as Note Pad or Simple Text) and save (Control-s or Command-s). The script is yours!!!

<!-- TWO STEPS TO INSTALL LATITUDE-LONGITUDE CONVERTER:

1.  Copy the coding into the HEAD of your HTML document
  2.  Add the last code into the BODY of your HTML document  -->

<HEAD>

function calc(Location) {
  // Retrieve the DD/DMS option
  for (var i=0;i<Location.inputType.length;i++) {
    if (Location.inputType[i].checked)
    {
      var inputed = Location.inputType[i].value;
    }
  }
  if (inputed == "DD")
  {
    // Retrieve Lat and Lon information
    var lat = Location.Latitude.value;
    var lon = Location.Longitude.value;
    if (lat==null)
    var lat=0;
    if (lon==null)
            var lon=0;

// Check if any error occurred
    if (isNaN(Location.Latitude.value) || isNaN(Location.Longitude.value)) {
      alert("Latitude and Longitude must be numeric");
    } else if (lat < -90 || lat > 90 || lon < -180 || lon > 180) {
            alert("ERROR");
    } else {
      //Retrieve the latitude direction for Degrees Decimal
      for (var i=0;i<Location.LatDirect.length;i++) {
        if (Location.LatDirect[i].checked)
        {
          var LatDirect = Location.LatDirect[i].value;
        }
      }

// If the user does not click direct button,
      // then a positive latitude value regards North, negative latitude value regards South
      if (LatDirect==null) {
        if (lat<0) {
          LatDirect = "S";
          Location.LatDirect[1].click();
        }
        else {
          LatDirect ="N";
          Location.LatDirect[0].click();
        }
      }

// Retrieve the longitude direction for Deg/Min/Sec
      for (var i=0;i<Location.LonDirect.length;i++) {
        if (Location.LonDirect[i].checked)
        {
          var LonDirect = Location.LonDirect[i].value;
        }
      }

// If the user does not click direct button,
      // then a positive latitude value regards East, negative latitude value regards West
      if (LonDirect==null) {
        if (lon<0) {
          LonDirect = "W";
          Location.LonDirect[1].click();
         }
        else {
          LonDirect ="E";
          Location.LonDirect[0].click();
        }
      }

// Change to absolute value
      lat = Math.abs(lat);
      lon = Math.abs(lon);
      Location.Latitude.value=lat;
      Location.Longitude.value=lon;
      setAllEnabled(Location);

// Convert to Degree Minutes Seconds Representation
      LatDeg = Math.floor(lat);
      LatMin = Math.floor((lat-LatDeg)*60);
      LatSec =  (Math.round((((lat - LatDeg) - (LatMin/60)) * 60 * 60) * 100) / 100 ) ;
      LonDeg = Math.floor(lon);
      LonMin = Math.floor((lon-LonDeg)*60);
      LonSec = (Math.round((((lon - LonDeg) - (LonMin / 60 )) * 60 * 60) * 100 ) / 100);

// Copy result to the board
      Location.LatDeg.value=LatDeg;
      Location.LatMin.value=LatMin;
      Location.LatSec.value=LatSec;
      Location.LonDeg.value=LonDeg;
      Location.LonMin.value=LonMin;
      Location.LonSec.value=LonSec;
      if (LatDirect == "N") {
        Location.LatDMSDirect[0].click();
      } else {
        Location.LatDMSDirect[1].click();
      }
      if (LonDirect == "E") {
        Location.LonDMSDirect[0].click();
      } else {
        Location.LonDMSDirect[1].click();
      }
      clickedOption(Location);

// Find the farthest Point Location
      farthestPoint(lat,lon,LatDeg,LonDeg,LatMin,LonMin,LatSec,LonSec,LatDirect,LonDirect);
    }
  } else if (inputed == "DMS") {

// Retrieve Lat and Lon information
    var LatDeg = Location.LatDeg.value;
    var LatMin = Location.LatMin.value;
    var LatSec = Location.LatSec.value;
    var LonDeg = Location.LonDeg.value;
    var LonMin = Location.LonMin.value;
    var LonSec = Location.LonSec.value;

// Assume the value to be zero if the user does not enter value
    if (LatDeg==null)
      LatDeg=0;
    if (LatMin==null) {
      LatMin=0;
    }
    if (LatSec==null) {
      LatSec=0;
    }
    if (LonDeg==null)
      LonDeg=0;
    if (LonMin==null) {
      LonMin=0
    }
    if (LonSec==null){
      LonSec=0;
    }

// Check if any error occurred
    if (isNaN(Location.LatDeg.value) || isNaN(Location.LonDeg.value) || isNaN(Location.LatMin.value) || isNaN(Location.LonMin.value) || isNaN(Location.LatSec.value) || isNaN(Location.LonSec.value)) {
      alert("Latitude and Longitude must be numeric");
    } else if (LatDeg != Math.round(LatDeg) || LonDeg != Math.round(LonDeg) || LatMin != Math.round(LatMin) || LonMin != Math.round(LonMin)) {
      alert("ERROR");
    } else if (LatDeg < -90 || LatDeg > 90 || LonDeg < -180 || LonDeg > 180 || LatMin < -60 || LatMin > 60 || LonMin < -60 || LonMin > 60 || LatSec < -60 || LatSec > 60 || LonSec < -60 || LonSec > 60) {
      alert("ERROR");
    } else {
    // If no error, then go on

// Retrieve the latitude direction for Degrees Decimal
    for (var i=0;i<Location.LatDMSDirect.length;i++) {
      if (Location.LatDMSDirect[i].checked)
      {
        var LatDMSDirect = Location.LatDMSDirect[i].value;
      }
    }

// If the user does not click direct button,
    // then a postive latitude value regards North, negative latitude value regards South
    if (LatDMSDirect==null) {
      if (LatDeg<0 || Location.LatDeg.value=="-0") {
        LatDMSDirect = "S";
        Location.LatDMSDirect[1].click();
      }
      else {
        LatDMSDirect ="N";
        Location.LatDMSDirect[0].click();
      }
    }

// Retrieve the longitude direction for Deg/Min/Sec
    for (var i=0;i<Location.LonDMSDirect.length;i++) {
      if (Location.LonDMSDirect[i].checked)
      {
        var LonDMSDirect = Location.LonDMSDirect[i].value;
      }
    }

// If the user does not click direct button,
    // then a positive latitude value regards East, negative latitude value regards West
    if (LonDMSDirect==null) {
      if (LonDeg<0 || Location.LonDeg.value=="-0") {
        LonDMSDirect = "W";
        Location.LonDMSDirect[1].click();
      } else {
        LonDMSDirect ="E";
        Location.LonDMSDirect[0].click();
      }
    }

// Change to absolute value
    LatDeg = Math.abs(LatDeg);
    LonDeg = Math.abs(LonDeg);
    LatMin = Math.abs(LatMin);
    LonMin = Math.abs(LonMin);
    LatSec = Math.abs(LatSec);
    LonSec = Math.abs(LonSec);
    setAllEnabled(Location);

// Convert to Decimal Degrees Representation
    var lat = LatDeg + (LatMin/60) + (LatSec / 60 / 60);
    var lon = LonDeg + (LonMin/60) + (LonSec / 60 / 60);
    if ( lat <= 90 && lon <= 180 && lat >=0 && lon >= 0 )
    {
      // Copy the absolute value to the board
      Location.LatDeg.value=LatDeg;
      Location.LonDeg.value=LonDeg;
      Location.LatMin.value=LatMin;
      Location.LonMin.value=LonMin;
      Location.LatSec.value=LatSec;
      Location.LonSec.value=LonSec;

// Rounding off
      lat = (Math.round(lat*1000000)/1000000);
      lon = (Math.round(lon*1000000)/1000000);

// Copy result to the board
      Location.Latitude.value=lat;
      Location.Longitude.value=lon;
      if (LatDMSDirect == "N") {
        Location.LatDirect[0].click();
      } else {
        Location.LatDirect[1].click();
      }
      if (LonDMSDirect == "E") {
        Location.LonDirect[0].click();
      } else {
        Location.LonDirect[1].click();
      }
        clickedOption(Location);
        farthestPoint(lat,lon,LatDeg,LonDeg,LatMin,LonMin,LatSec,LonSec,LatDMSDirect,LonDMSDirect);
      } else
        alert("ERROR!!");
    }
  }
}

function resetForm(Location) {
        changeOption(Location,"DD");
}

function setAllEnabled(Location) {
  with (Location) {
    Latitude.disabled=false;
    Longitude.disabled=false;
    LatDeg.disabled=false;
    LonDeg.disabled=false;
    LatMin.disabled=false;
    LonMin.disabled=false;
    LatSec.disabled=false;
    LonSec.disabled=false;
    LatDMSDirect[0].disabled=false;
    LonDMSDirect[0].disabled=false;
    LatDMSDirect[1].disabled=false;
    LonDMSDirect[1].disabled=false;
    LatDirect[0].disabled=false;
    LonDirect[0].disabled=false;
    LatDirect[1].disabled=false;
    LonDirect[1].disabled=false;
  }
}

// Method 1
  farLonDeg = Math.floor(farLon);
  farLonMin = Math.floor((farLon-farLonDeg)*60);
  farLonSec = (Math.round((((farLon - farLonDeg) - (farLonMin / 60 )) * 60 * 60) * 100 ) / 100);

// Method 2
  /*
    farLonSec = 60 - LonSec;
    if (farLonSec == 60) {
      farLonSec=0;
    }
    if (farLonSec >0) {
      farLonMin = 60 - LonMin - 1;
    } else {
      farLonMin = 60 - LonMin ;
    }
    if (farLonMin ==60) {
      farLonMin =0;
    }
    if (farLonMin >0) {
      farLonDeg = 180 - Math.abs(farLonDeg) - 1;
    } else {
      farLonDeg = 180 - Math.abs(farLonDeg);
    }
  */
  farLon = Math.round(farLon*1000000)/1000000;
  farLonSec = Math.round(farLonSec*100)/100;
  elev = 200;
  farElev = 200;
  var dist = distance(lat,LatDirect,lon,LonDirect,elev,farLat,farLatDirect,farLon,farLonDirect,farElev);
  var alertMsg="";
  alertMsg+=("The location you entered is : " + "\n\n" +
  "Latitude: " + lat + " " + LatDirect + "\n" + "Degrees: " + LatDeg + " Minutes: " + LatMin + " Seconds: " + LatSec + " " + LatDirect + "\n\n" +
  "Longitude: " + lon + " " + LonDirect + "\n" + "Degrees: " + LonDeg + " Minutes: " + LonMin + " Seconds: " + LonSec + " " + LonDirect + "\n\n" +
  "---------------------------------------------------------------" + "\n");

alertMsg+=("The farthest location from the point you entered is : " + "\n\n" +
  "Latitude: " + farLat + " " + farLatDirect + "\n" + "Degrees: " + farLatDeg + " Minutes: " + farLatMin + " Seconds: " + farLatSec + " " + farLatDirect + "\n\n" +
  "Longitude: " + farLon + " " + farLonDirect + "\n" + "Degrees: " + farLonDeg + " Minutes: " + farLonMin + " Seconds: " + farLonSec + " " + farLonDirect + "\n\n");

alertMsg+=("---------------------------------------------------------------" + "\n");
  alertMsg+=("Distance: " + dist + " km ");

alert(alertMsg);
}

function distance(lat,LatDirect,lon,LonDirect,elev,lat2,ptDirect,lon2,ptLonDirect,ptElev) {
  var radLat,radLon,radLat2,radLon2;
  if (ptDirect == "S")
    lat2 = lat2*-1;
  if (ptLonDirect == "W")
    lon2 = lon2*-1;
  if (LatDirect == "S")
    lat = lat*-1;
  if (LonDirect == "W")
    lon = lon*-1;
  var radian = 180/Math.PI;
  radLat=lat/radian;
  radLon=lon/radian;
  radLat2=lat2/radian;
  radLon2=lon2/radian;
  var dist = calcDistance(radLat,radLon,elev,radLat2,radLon2,ptElev);
  dist = Math.round(dist*100)/100;
  return dist;
}

// calculate the distance between two coordinates
function calcDistance(lat1,long1,elev,lat2,long2,ptElev) {
  var earthEquatorialRadius = 6378.14; // in kilometers
  var earthFlattened = 1/298.257;
  var exCentricityEarth = 0.08181922;
  var radian = 180/Math.PI;
  meanPosLat = (lat1+lat2)/2;
  meanNegLat = (lat1-lat2)/2;
  lambda = (long1-long2)/2;
  with(Math) {
    si = pow(sin(meanNegLat)*cos(lambda),2)+pow(cos(meanPosLat)*sin(lambda),2);
    co = pow(cos(meanNegLat)*cos(lambda),2)+pow(sin(meanPosLat)*sin(lambda),2);
    delta = atan(sqrt(si/co));
    ra = sqrt(si*co)/delta;
    di = 2*delta*earthEquatorialRadius;
    ha =(3*ra-1)/2/co;
    hb =(3*ra+1)/2/si;
    distances = di*(1+earthFlattened*ha*pow(sin(meanPosLat)*cos(meanNegLat),2)-earthFlattened*hb*pow(cos(meanPosLat)*sin(meanNegLat),2));
  }

// Taking elevation into consideration
  var totalElev, elevDist
  totalElevDist = Math.abs(elev - ptElev);

// Convert back to km
  totalElevDist = totalElevDist / 1000;
  elevDist = Math.sqrt((distances * distances) + (totalElevDist * totalElevDist));
  return elevDist;
}
// -->
</script>
</HEAD>

<BODY>

<div id="demo">
<form name="Locations">
<input class="script" type="radio" name="inputType" value="DD" checked onclick="clickedOption(this.form)"> <strong>Degrees Decimal</strong>

<br>Latitude   : <input class="script" name="Latitude" type="text" size="5">  North <input class="script" type="radio" name="LatDirect" value="N"> South <input class="script" type="radio" name="LatDirect" value="S">
<br>Longitude: <input class="script" name="Longitude" type="text" size="5">  East  <input class="script" type="radio" name="LonDirect" value="E"> West  <input class="script" type="radio" name="LonDirect" value="W">
<br>

<br><input class="script" type="radio" name="inputType" value="DMS" onclick="clickedOption(this.form)"> <strong>Degrees, Minutes, & Seconds</strong>
<br><strong>Latitude:</strong>
<br>Degrees: <input class="script" name="LatDeg" type="text" size="5" disabled>  Minutes: <input class="script" name="LatMin" type="text" size="5" disabled>  Seconds: <input class="script" name="LatSec" type="text" size="5" disabled>
<br>  North <input class="script" type="radio" name="LatDMSDirect" value="N" disabled>  South <input class="script" type="radio" name="LatDMSDirect" value="S" disabled>
<br><strong>Longitude:</strong>
<br>Degrees: <input class="script" name="LonDeg" type="text" size="5" disabled>  Minutes: <input class="script" name="LonMin" type="text" size="5" disabled>  Seconds: <input class="script" name="LonSec" type="text" size="5" disabled>
<br>  East  <input class="script" type="radio" name="LonDMSDirect" value="E" disabled>    West <input class="script" type="radio" name="LonDMSDirect" value="W" disabled>

<p><center>
<font face="arial, helvetica" size"-2">Free JavaScripts provided<br>
by <a href="http://javascriptsource.com">The JavaScript Source</a></font>
</center><p>

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Latitude-Longitude Converter

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