code: public int getSequenceNumber(Coordinate coord) {
  		int minIndex = 0;
  		double minDist = Double.MAX_VALUE;
  		for (int i = 0; i < this.getPositions().length; i++) {
  			if (this.getPositions()[i].distance(coord) < minDist) {
  				minDist = this.getPositions()[i].distance(coord);
  				minIndex = i;
  			}
  		}
  		return minIndex;
  	}
docs: Get the sequence number of the path point that is closest to a
  given coordinate.
  @param coord The coordinate to which the closest sequence number should be found.
  @return The sequence number of the path point that is closest to the given coordinate.