public void suggest(File locationFile, int locationListSize, File outputFile, int hubSize) {
// WARNING: this code is VERY DIRTY.
// It's JUST good enough to generate the hubs for Belgium once (because we only need to
// determine them once).
// Further research to generate good hubs is needed.
List<AirLocation> locationList = readAirLocationFile(locationFile);
if (locationListSize > locationList.size()) {
throw new IllegalArgumentException(
"The locationListSize ("
+ locationListSize
+ ") is larger than the locationList size ("
+ locationList.size()
+ ").");
}
locationList = subselectLocationList(locationListSize, locationList);
Map<Point, Point> fromPointMap = new LinkedHashMap<Point, Point>(locationListSize * 10);
Map<Point, Point> toPointMap = new LinkedHashMap<Point, Point>(locationListSize * 10);
int rowIndex = 0;
double maxAirDistance = 0.0;
for (AirLocation fromAirLocation : locationList) {
for (AirLocation toAirLocation : locationList) {
double airDistance = fromAirLocation.getAirDistanceDouble(toAirLocation);
if (airDistance > maxAirDistance) {
maxAirDistance = airDistance;
}
}
}
double airDistanceThreshold = maxAirDistance / 10.0;
for (AirLocation fromAirLocation : locationList) {
for (AirLocation toAirLocation : locationList) {
double distance;
if (fromAirLocation != toAirLocation) {
GHRequest request =
new GHRequest(
fromAirLocation.getLatitude(),
fromAirLocation.getLongitude(),
toAirLocation.getLatitude(),
toAirLocation.getLongitude())
.setVehicle("car");
GHResponse response = graphHopper.route(request);
if (response.hasErrors()) {
throw new IllegalStateException(
"GraphHopper gave " + response.getErrors().size() + " errors. First error chained.",
response.getErrors().get(0));
}
// Distance should be in km, not meter
distance = response.getDistance() / 1000.0;
if (distance == 0.0) {
throw new IllegalArgumentException(
"The fromAirLocation ("
+ fromAirLocation
+ ") and toAirLocation ("
+ toAirLocation
+ ") are the same.");
}
PointList ghPointList = response.getPoints();
PointPart previousFromPointPart = null;
PointPart previousToPointPart = null;
double previousLatitude = Double.NaN;
double previousLongitude = Double.NaN;
for (int i = 0; i < ghPointList.size(); i++) {
double latitude = ghPointList.getLatitude(i);
double longitude = ghPointList.getLongitude(i);
if (latitude == previousLatitude && longitude == previousLongitude) {
continue;
}
if (calcAirDistance(
latitude,
longitude,
fromAirLocation.getLatitude(),
fromAirLocation.getLongitude())
< airDistanceThreshold) {
Point fromPoint = new Point(latitude, longitude);
Point oldFromPoint = fromPointMap.get(fromPoint);
if (oldFromPoint == null) {
// Initialize fromPoint instance
fromPoint.pointPartMap = new LinkedHashMap<AirLocation, PointPart>();
fromPointMap.put(fromPoint, fromPoint);
} else {
// Reuse existing fromPoint instance
fromPoint = oldFromPoint;
}
PointPart fromPointPart = fromPoint.pointPartMap.get(fromAirLocation);
if (fromPointPart == null) {
fromPointPart = new PointPart(fromPoint, fromAirLocation);
fromPoint.pointPartMap.put(fromAirLocation, fromPointPart);
fromPointPart.previousPart = previousFromPointPart;
}
fromPointPart.count++;
previousFromPointPart = fromPointPart;
}
if (calcAirDistance(
latitude, longitude, toAirLocation.getLatitude(), toAirLocation.getLongitude())
< airDistanceThreshold) {
Point toPoint = new Point(latitude, longitude);
Point oldToPoint = toPointMap.get(toPoint);
if (oldToPoint == null) {
// Initialize toPoint instance
toPoint.pointPartMap = new LinkedHashMap<AirLocation, PointPart>();
toPointMap.put(toPoint, toPoint);
} else {
// Reuse existing toPoint instance
toPoint = oldToPoint;
}
// Basically do the same as fromPointPart, but while traversing in the other direction
PointPart toPointPart = toPoint.pointPartMap.get(toAirLocation);
boolean newToPointPart = false;
if (toPointPart == null) {
toPointPart = new PointPart(toPoint, toAirLocation);
toPoint.pointPartMap.put(toAirLocation, toPointPart);
newToPointPart = true;
}
if (previousToPointPart != null) {
previousToPointPart.previousPart = toPointPart;
}
toPointPart.count++;
if (newToPointPart) {
previousToPointPart = toPointPart;
} else {
previousToPointPart = null;
}
}
previousLatitude = latitude;
previousLongitude = longitude;
}
}
}
logger.debug(" Finished routes for rowIndex {}/{}", rowIndex, locationList.size());
rowIndex++;
}
Set<Point> hubPointList = new LinkedHashSet<Point>(20);
extractFromHubs(new ArrayList<Point>(fromPointMap.values()), hubPointList, (hubSize + 1) / 2);
extractFromHubs(new ArrayList<Point>(toPointMap.values()), hubPointList, hubSize / 2);
logger.info("Writing hubs...");
BufferedWriter vrpWriter = null;
try {
vrpWriter =
new BufferedWriter(new OutputStreamWriter(new FileOutputStream(outputFile), "UTF-8"));
vrpWriter.write("HUB_COORD_SECTION\n");
int id = 0;
for (Point point : hubPointList) {
vrpWriter.write("" + id + " " + point.latitude + " " + point.longitude + " " + id + "\n");
id++;
}
vrpWriter.write("\n\nGOOGLE MAPS\n");
for (Point point : hubPointList) {
vrpWriter.write("" + id + "\t0\t" + point.latitude + "," + point.longitude + "\n");
id++;
}
} catch (IOException e) {
throw new IllegalArgumentException(
"Could not read the locationFile ("
+ locationFile.getName()
+ ") or write the vrpOutputFile ("
+ outputFile.getName()
+ ").",
e);
} finally {
IOUtils.closeQuietly(vrpWriter);
}
// Throw in google docs spreadsheet and use add-on Mapping Sheets to visualize.
}
private void extractFromHubs(List<Point> pointList, Set<Point> hubPointList, int hubSize) {
// logger.info("Filtering points below threshold...");
// fromPointMap = null;
// int THRESHOLD = 10;
// for (Iterator<Point> it = pointList.iterator(); it.hasNext(); ) {
// Point point = it.next();
// if (point.pointPartMap.values().size() < THRESHOLD) {
// it.remove();
// point.removed = true;
// }
// }
// for (Point point : pointList) {
// for (PointPart pointPart : point.pointPartMap.values()) {
// PointPart previousPart = pointPart.previousPart;
// while (previousPart != null && previousPart.point.removed) {
// previousPart = previousPart.previousPart;
// }
// pointPart.previousPart = previousPart;
// }
// }
logger.info("Extracting hubs...");
for (int i = 0; i < hubSize; i++) {
logger.info(" {} / {} with remaining pointListSize ({})", i, hubSize, pointList.size());
// Make the biggest merger of 2 big streams into 1 stream a hub.
int maxCount = -1;
Point maxCountPoint = null;
for (Point point : pointList) {
int count = 0;
for (PointPart pointPart : point.pointPartMap.values()) {
count += pointPart.count;
}
if (count > maxCount) {
maxCount = count;
maxCountPoint = point;
}
}
if (maxCountPoint == null) {
throw new IllegalStateException("No maxCountPoint (" + maxCountPoint + ") found.");
}
maxCountPoint.hub = true;
pointList.remove(maxCountPoint);
hubPointList.add(maxCountPoint);
// Remove trailing parts
for (Iterator<Point> pointIt = pointList.iterator(); pointIt.hasNext(); ) {
Point point = pointIt.next();
for (Iterator<PointPart> partIt = point.pointPartMap.values().iterator();
partIt.hasNext(); ) {
PointPart pointPart = partIt.next();
if (pointPart.comesAfterHub()) {
partIt.remove();
}
}
if (point.pointPartMap.isEmpty()) {
point.removed = true;
pointIt.remove();
}
}
// Subtract prefix parts
for (PointPart pointPart : maxCountPoint.pointPartMap.values()) {
PointPart ancestorPart = pointPart.previousPart;
while (ancestorPart != null) {
ancestorPart.count -= pointPart.count;
// if (ancestorPart.count < 0) {
// throw new IllegalStateException("Impossible state"); // TODO
// FIXME Does happen! Probably because some paths hit the same point twice at different
// elevation
// }
if (ancestorPart.count <= 0) {
ancestorPart.point.pointPartMap.remove(ancestorPart.anchor);
}
ancestorPart = ancestorPart.previousPart;
}
}
}
}