code: public static Coverage coverBoundingBox(double topLeftLat, final double topLeftLon,
              final double bottomRightLat, final double bottomRightLon, final int length) {
          return new Coverage(coverBoundingBoxLongs(topLeftLat, topLeftLon, bottomRightLat,
                  bottomRightLon, length));
      }
docs: Returns the hashes of given length that are required to cover the given
  bounding box.
  
  @param topLeftLat
  latitude of top left point (north west)
  @param topLeftLon
  longitude of top left point (north west)
  @param bottomRightLat
  latitude of bottom right point (south east)
  @param bottomRightLon
  longitude of bottom right point (south east)
  @param length
  of hash
  @return number of hashes of given length required to cover the given
  bounding box