private Map<Integer, Waypoint> createWaypointByWaypointId() {
		Map<Integer, Waypoint> waypointByWaypointIdMap = new TreeMap<Integer, Waypoint>();
		for (Waypoint wPoint : waypoints) {
			waypointByWaypointIdMap.put(wPoint.getId(), wPoint);
		}
		return waypointByWaypointIdMap;
	}
	private List<Waypoint> createAllWaypointsFromExternalFile()
			throws IOException {
		List<Waypoint> result = new ArrayList<Waypoint>();
		String fileName = "waypoints.csv";
		InputStream is = context.getAssets().open(fileName);
		InputStreamReader isr = new InputStreamReader(is);
		BufferedReader br = new BufferedReader(isr);
		String readStr;
		br.readLine(); // 첫 줄 버림.
		while ((readStr = br.readLine()) != null) {
			String[] tokens = readStr.split(delimiter);
			Waypoint wayPoint = new Waypoint();
			wayPoint.setId(Integer.parseInt(tokens[0]));
			wayPoint.setX(Double.parseDouble(tokens[1]));
			wayPoint.se		Integer avgSignalStrength = 0;
				for (Integer signalStrength : signalsByApId.get(apId)) {
					avgSignalStrength = avgSignalStrength + signalStrength;
				}
				avgSignalStrength = (int) ((double) avgSignalStrength / (double) signalsByApId
						.get(apId).size());
				representiveApSet.add(new ApSet(fingerprintId, apId,
						avgSignalStrength));
			}
			newApSets.addAll(representiveApSet);
			Fingerprint representiveFingerprint = new Fingerprint(
					fingerprintId, time, x, y, z);
			this.fingerprints.add(representiveFingerprint);
			this.fingerprintByFingerprintIdMap.put(fingerprintId,
					representiveFingerprint);
			newFingerprintByCoordinateMap.put(coordinate,
					representiveFingerprint);
			newApSetsByFingerprintIdMap.put(fingerprintId, representiveApSet);
			fingerprintId++;
		}
	private Map<Double, List<WaypointLink>> createWaypointLinksByZ() {
		Map<Double, List<WaypointLink>> waypointLinksByZMap = new TreeMap<Double, List<WaypointLink>>();
		for (WaypointLink wayLink : waypointLinks) {
			Waypoint waypoint = waypointByWaypointIdMap.get(wayLink
					.getStartPointId());
			if (waypointLinksByZMap.get(waypoint.getZ()) == null) {
				waypointLinksByZMap.put(waypoint.getZ(),
						new ArrayList<WaypointLink>());
			}
			waypointLinksByZMap.get(waypoint.getZ()).add(wayLink);
		}
		return waypointLinksByZMap;
	}