code: public boolean equals3D(final Coordinate other) {
          return getX() == other.getX() && getY() == other.getY()
                  && (getZ() == other.getZ() || Double.isNaN(getZ()) && Double.isNaN(other.getZ()));
      }
docs: Tests if another coordinate has the same values for the X, Y and Z ordinates.
  
  @param other
  a <code>Coordinate</code> with which to do the 3D comparison.
  @return true if <code>other</code> is a <code>Coordinate</code> with the same values for X, Y
  and Z.