Used for an ethereum smart-contract project to store coordinates as int256 in Solidity.

Encode coordinates as ints

function pad(n, len=6) {
  n = n.toString();
  n.trim();
  let q = n.length;
  for(let i=q; i<len; i++) {
    n = "0"+n;
  }
  return n;
}

function parseToFxLengStr(n) {
  let isNeg = n < 0;
  let m = n.toFixed(3).toString().replace('.', '').replace('-', '');
  m = pad(m);
  if(isNeg) m = "1" + m;
  else m = "0" + m;
  return m
}

// Encode world coordinates as ints.
function encodeCoord(coord) {
  let la = parseToFxLengStr(coord.Latitude);
  let lo = parseToFxLengStr(coord.Longitude);
  let loc = la + lo;
  let i = parseInt(loc);
  return i;
}

// decode a string representation of the coordinates to a coordinate object
function decodeCoord(str) {
  let paddedStr = pad(str, 14);
  let laEnc = paddedStr.slice(0, 7);
  let loEnc = paddedStr.slice(7, paddedStr.length);
  let laIsNeg = (laEnc.charAt(0) == '1');
  let loIsNeg = (loEnc.charAt(0) == '1');

  laEnc = laEnc.slice(1, laEnc.length);
  loEnc = loEnc.slice(1, loEnc.length);

  laEnc = [laEnc.slice(0, 3), '.', laEnc.slice(3)].join('');
  loEnc = [loEnc.slice(0, 3), '.', loEnc.slice(3)].join('');

  let la = parseFloat(laEnc) * ((laIsNeg) ? -1 : 1);
  let lo = parseFloat(loEnc) * ((loIsNeg) ? -1 : 1);

  return { "latitude": la, "longitude": lo };
}