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Encoding Latitude and Longitude pairs for performance - javascript encode

This function encodes an array of VELatLong into a string for simplicity and performance.

// Encode a signed number in the encode format.
function encodeSignedNumber(num) {
  var sgn_num = num << 1;

  if (num < 0) {
    sgn_num = ~(sgn_num);
  }

  return(encodeNumber(sgn_num));
}

// Encode an unsigned number in the encode format.
function encodeNumber(num) {
  var encodeString = "";

  while (num >= 0x20) {
    encodeString += (String.fromCharCode((0x20 | (num & 0x1f)) + 63));
    num >>= 5;
  }

  encodeString += (String.fromCharCode(num + 63));
  return encodeString;
}

// Create the encoded bounds.
function createEncodings(points) {
  var i = 0;
  var plat = 0;
  var plng = 0;
  var encoded_points = "";

  for(i = 0; i < points.length; ++i) {
    var point = points[i];
    var lat = point.Latitude;
    var lng = point.Longitude;

    var late5 = Math.floor(lat * 1e5);
    var lnge5 = Math.floor(lng * 1e5);

    dlat = late5 - plat;
    dlng = lnge5 - plng;

    plat = late5;
    plng = lnge5;

    encoded_points += encodeSignedNumber(dlat) + encodeSignedNumber(dlng);
  } 
  return encoded_points;
}