docs: function(line) {
    const length = getLength(line);
    let output;
    if (length > 100) {
      output = (Math.round(length / 1000 * 100) / 100) +
          ' ' + 'km';
    } else {
      output = (Math.round(length * 100) / 100) +
          ' ' + 'm';
    }
    return output;
  }