private FeatureCollection convexHhull(TaskMonitor monitor, FeatureCollection fc) {
monitor.allowCancellationRequests();
monitor.report(I18N.get("ui.plugin.analysis.ConvexHullPlugIn.Computing-Convex-Hull") + "...");
int size = fc.size();
GeometryFactory geomFact = null;
if (size == 0) {
return null;
}
int count = 0;
Geometry[] geoms = new Geometry[size];
for (Iterator i = fc.iterator(); i.hasNext(); ) {
Feature f = (Feature) i.next();
Geometry geom = f.getGeometry();
if (geom == null) {
continue;
}
if (geomFact == null) {
geomFact = geom.getFactory();
}
geoms[count++] = geom;
}
GeometryCollection gc = geomFact.createGeometryCollection(geoms);
Geometry hull = gc.convexHull();
List hullList = new ArrayList();
hullList.add(hull);
return FeatureDatasetFactory.createFromGeometry(hullList);
}
/**
* Calculates walksheds for a given location, based on time given to walk and the walk speed.
*
* <p>Depending on the value for the "output" parameter (i.e. "POINTS", "SHED" or "EDGES"), a
* different type of GeoJSON geometry is returned. If a SHED is requested, then a ConcaveHull of
* the EDGES/roads is returned. If that fails, a ConvexHull will be returned.
*
* <p>The ConcaveHull parameter is set to 0.005 degrees. The offroad walkspeed is assumed to be
* 0.83333 m/sec (= 3km/h) until a road is hit.
*
* <p>Note that the set of EDGES/roads returned as well as POINTS returned may contain duplicates.
* If POINTS are requested, then not the end-points are returned at which the max time is reached,
* but instead all the graph nodes/crossings that are within the time limits.
*
* <p>In case there is no road near by within the given time, then a circle for the walktime limit
* is created and returned for the SHED parameter. Otherwise the edge with the direction towards
* the closest road. Note that the circle is calculated in Euclidian 2D coordinates, and
* distortions towards an ellipse will appear if it is transformed/projected to the user location.
*
* <p>An example request may look like this:
* localhost:8080/otp-rest-servlet/ws/iso?layers=traveltime&styles=mask&batch=true&fromPlace=51.040193121307176
* %2C-114.04471635818481&toPlace
* =51.09098935%2C-113.95179705&time=2012-06-06T08%3A00%3A00&mode=WALK&maxWalkDistance=10000&walkSpeed=1.38&walkTime=10.7&output=EDGES
* Though the first parameters (i) layer, (ii) styles and (iii) batch could be discarded.
*
* @param walkmins Maximum number of minutes to walk.
* @param output Can be set to "POINTS", "SHED" or "EDGES" to return different types of GeoJSON
* geometry. SHED returns a ConcaveHull or ConvexHull of the edges/roads. POINTS returns all
* graph nodes that are within the time limit.
* @return a JSON document containing geometries (either points, lineStrings or a polygon).
* @throws Exception
* @author sstein---geo.uzh.ch
*/
@GET
@Produces({MediaType.APPLICATION_JSON})
public String getIsochrone(
@QueryParam("walkTime") @DefaultValue("15") double walkmins,
@QueryParam("output") @DefaultValue("POINTS") String output)
throws Exception {
this.debugGeoms = new ArrayList();
this.tooFastTraversedEdgeGeoms = new ArrayList();
RoutingRequest sptRequestA = buildRequest(0);
String from = sptRequestA.getFrom().toString();
int pos = 1;
float lat = 0;
float lon = 0;
for (String s : from.split(",")) {
if (s.isEmpty()) {
// no location
Response.status(Status.BAD_REQUEST).entity("no position").build();
return null;
}
try {
float num = Float.parseFloat(s);
if (pos == 1) {
lat = num;
}
if (pos == 2) {
lon = num;
}
} catch (Exception e) {
throw new WebApplicationException(
Response.status(Status.BAD_REQUEST)
.entity(
"Could not parse position string to number. Require numerical lat & long coords.")
.build());
}
pos++;
}
GeometryFactory gf = new GeometryFactory();
Coordinate dropPoint = new Coordinate(lon, lat);
int walkInMin = (int) Math.floor(walkmins);
double walkInSec = walkmins * 60;
LOG.debug(
"given travel time: " + walkInMin + " mins + " + (walkInSec - (60 * walkInMin)) + " sec");
// restrict the evaluated SPT size to 30mins for requests with walking < 30min
// if larger walking times are requested we adjust the evaluated
// graph dynamically by 1.3 * min -> this should save processing time
if (walkInMin < 30) {
sptRequestA.worstTime = sptRequestA.dateTime + (30 * 60);
} else {
sptRequestA.worstTime = sptRequestA.dateTime + Math.round(walkInMin * 1.3 * 60);
}
// set the switch-time for shed/area calculation, i.e. to decide if the hull is calculated based
// on points or on edges
TraverseModeSet modes = sptRequestA.modes;
LOG.debug("mode(s): " + modes);
if ((modes.contains(TraverseMode.TRANSIT))
|| (modes.contains(TraverseMode.BUSISH))
|| (modes.contains(TraverseMode.TRAINISH))) {
shedCalcMethodSwitchTimeInSec =
60 * 20; // 20min (use 20min for transit, since buses may not come all the time)
} else if (modes.contains(TraverseMode.CAR)) {
shedCalcMethodSwitchTimeInSec = 60 * 10; // 10min
} else if (modes.contains(TraverseMode.BICYCLE)) {
shedCalcMethodSwitchTimeInSec = 60 * 10; // 10min
} else {
shedCalcMethodSwitchTimeInSec = 60 * 20; // 20min
}
// set the maxUserSpeed, which is used later to check for u-type streets/crescents when
// calculating sub-edges;
// Note, that the car speed depends on the edge itself, so this value may be replaced later
this.usesCar = false;
int numberOfModes = modes.getModes().size();
if (numberOfModes == 1) {
if (modes.getWalk()) {
this.maxUserSpeed = sptRequestA.getWalkSpeed();
} else if (modes.getBicycle()) {
this.maxUserSpeed = sptRequestA.getBikeSpeed();
} else if (modes.getDriving()) {
this.maxUserSpeed = sptRequestA.getCarSpeed();
this.usesCar = true;
}
} else { // for all other cases (multiple-modes)
// sstein: I thought I may set it to 36.111 m/sec = 130 km/h,
// but maybe it is better to assume walk speed for transit, i.e. treat it like if the
// person gets off the bus on the last crossing and walks the "last mile".
this.maxUserSpeed = sptRequestA.getWalkSpeed();
}
if (doSpeedTest) {
LOG.debug("performing angle and speed based test to detect u-shapes");
} else {
LOG.debug("performing only angle based test to detect u-shapes");
}
// TODO: OTP prefers to snap to car-roads/ways, which is not so nice, when walking,
// and a footpath is closer by. So far there is no option to switch that off
// create the ShortestPathTree
try {
sptRequestA.setRoutingContext(graphService.getGraph());
} catch (Exception e) {
// if we get an exception here, and in particular a VertexNotFoundException,
// then it is likely that we chose a (transit) mode without having that (transit) modes data
LOG.debug("cannot set RoutingContext: " + e.toString());
LOG.debug("cannot set RoutingContext: setting mode=WALK");
sptRequestA.setMode(TraverseMode.WALK); // fall back to walk mode
sptRequestA.setRoutingContext(graphService.getGraph());
}
ShortestPathTree sptA = sptService.getShortestPathTree(sptRequestA);
StreetLocation origin = (StreetLocation) sptRequestA.rctx.fromVertex;
sptRequestA.cleanup(); // remove inserted points
// create a LineString for display
Coordinate pathToStreetCoords[] = new Coordinate[2];
pathToStreetCoords[0] = dropPoint;
pathToStreetCoords[1] = origin.getCoordinate();
LineString pathToStreet = gf.createLineString(pathToStreetCoords);
// get distance between origin and drop point for time correction
double distanceToRoad =
this.distanceLibrary.distance(origin.getY(), origin.getX(), dropPoint.y, dropPoint.x);
long offRoadTimeCorrection = (long) (distanceToRoad / this.offRoadWalkspeed);
//
// --- filter the states ---
//
Set<Coordinate> visitedCoords = new HashSet<Coordinate>();
ArrayList<Edge> allConnectingEdges = new ArrayList<Edge>();
Coordinate coords[] = null;
long maxTime = (long) walkInSec - offRoadTimeCorrection;
// System.out.println("Reducing walktime from: " + (int)(walkmins * 60) + "sec to " + maxTime +
// "sec due to initial walk of " + distanceToRoad
// + "m");
// if the initial walk is already to long, there is no need to parse...
if (maxTime <= 0) {
noRoadNearBy = true;
long timeToWalk = (long) walkInSec;
long timeBetweenStates = offRoadTimeCorrection;
long timeMissing = timeToWalk;
double fraction = (double) timeMissing / (double) timeBetweenStates;
pathToStreet = getSubLineString(pathToStreet, fraction);
LOG.debug(
"no street found within giving travel time (for off-road walkspeed: {} m/sec)",
this.offRoadWalkspeed);
} else {
noRoadNearBy = false;
Map<ReversibleLineStringWrapper, Edge> connectingEdgesMap = Maps.newHashMap();
for (State state : sptA.getAllStates()) {
long et = state.getElapsedTimeSeconds();
if (et <= maxTime) {
// -- filter points, as the same coordinate may be passed several times due to the graph
// structure
// in a Calgary suburb family homes neighborhood with a 15min walkshed it filtered about
// 250 points away (while 145 were finally displayed)
if (visitedCoords.contains(state.getVertex().getCoordinate())) {
continue;
} else {
visitedCoords.add(state.getVertex().getCoordinate());
}
// -- get all Edges needed later for the edge representation
// and to calculate an edge-based walkshed
// Note, it can happen that we get a null geometry here, e.g. for hop-edges!
Collection<Edge> vertexEdgesIn = state.getVertex().getIncoming();
for (Iterator<Edge> iterator = vertexEdgesIn.iterator(); iterator.hasNext(); ) {
Edge edge = (Edge) iterator.next();
Geometry edgeGeom = edge.getGeometry();
if (edgeGeom != null) { // make sure we get only real edges
if (edgeGeom instanceof LineString) {
// allConnectingEdges.add(edge); // instead of this, use a map now, so we don't have
// similar edge many times
connectingEdgesMap.put(
new ReversibleLineStringWrapper((LineString) edgeGeom), edge);
}
}
}
Collection<Edge> vertexEdgesOut = state.getVertex().getOutgoing();
for (Iterator<Edge> iterator = vertexEdgesOut.iterator(); iterator.hasNext(); ) {
Edge edge = (Edge) iterator.next();
Geometry edgeGeom = edge.getGeometry();
if (edgeGeom != null) {
if (edgeGeom instanceof LineString) {
// allConnectingEdges.add(edge); // instead of this, use a map now, so we don't
// similar edge many times
connectingEdgesMap.put(
new ReversibleLineStringWrapper((LineString) edgeGeom), edge);
}
}
}
} // end : if(et < maxTime)
}
// --
// points from list to array, for later
coords = new Coordinate[visitedCoords.size()];
int i = 0;
for (Coordinate c : visitedCoords) coords[i++] = c;
// connection edges from Map to List
allConnectingEdges.clear();
for (Edge tedge : connectingEdgesMap.values()) allConnectingEdges.add(tedge);
}
StringWriter sw = new StringWriter();
GeoJSONBuilder json = new GeoJSONBuilder(sw);
//
// -- create the different outputs ---
//
try {
if (output.equals(IsoChrone.RESULT_TYPE_POINTS)) {
// in case there was no road we create a circle and
// and return those points
if (noRoadNearBy) {
Geometry circleShape = createCirle(dropPoint, pathToStreet);
coords = circleShape.getCoordinates();
}
// -- the states/nodes with time elapsed <= X min.
LOG.debug("write multipoint geom with {} points", coords.length);
json.writeGeom(gf.createMultiPoint(coords));
LOG.debug("done");
} else if (output.equals(IsoChrone.RESULT_TYPE_SHED)) {
Geometry geomsArray[] = null;
// in case there was no road we create a circle
if (noRoadNearBy) {
Geometry circleShape = createCirle(dropPoint, pathToStreet);
json.writeGeom(circleShape);
} else {
if (maxTime > shedCalcMethodSwitchTimeInSec) { // eg., walkshed > 20 min
// -- create a point-based walkshed
// less exact and should be used for large walksheds with many edges
LOG.debug("create point-based shed (not from edges)");
geomsArray = new Geometry[coords.length];
for (int j = 0; j < geomsArray.length; j++) {
geomsArray[j] = gf.createPoint(coords[j]);
}
} else {
// -- create an edge-based walkshed
// it is more exact and should be used for short walks
LOG.debug("create edge-based shed (not from points)");
Map<ReversibleLineStringWrapper, LineString> walkShedEdges = Maps.newHashMap();
// add the walk from the pushpin to closest street point
walkShedEdges.put(new ReversibleLineStringWrapper(pathToStreet), pathToStreet);
// get the edges and edge parts within time limits
ArrayList<LineString> withinTimeEdges =
this.getLinesAndSubEdgesWithinMaxTime(
maxTime,
allConnectingEdges,
sptA,
angleLimitForUShapeDetection,
distanceToleranceForUShapeDetection,
maxUserSpeed,
usesCar,
doSpeedTest);
for (LineString ls : withinTimeEdges) {
walkShedEdges.put(new ReversibleLineStringWrapper(ls), ls);
}
geomsArray = new Geometry[walkShedEdges.size()];
int k = 0;
for (LineString ls : walkShedEdges.values()) geomsArray[k++] = ls;
} // end if-else: maxTime condition
GeometryCollection gc = gf.createGeometryCollection(geomsArray);
// create the concave hull, but in case it fails we just return the convex hull
Geometry outputHull = null;
LOG.debug(
"create concave hull from {} geoms with edge length limit of about {} m (distance on meridian)",
geomsArray.length,
concaveHullAlpha * 111132);
// 1deg at Latitude phi = 45deg is about 111.132km
// (see wikipedia:
// http://en.wikipedia.org/wiki/Latitude#The_length_of_a_degree_of_latitude)
try {
ConcaveHull hull = new ConcaveHull(gc, concaveHullAlpha);
outputHull = hull.getConcaveHull();
} catch (Exception e) {
outputHull = gc.convexHull();
LOG.debug("Could not generate ConcaveHull for WalkShed, using ConvexHull instead.");
}
LOG.debug("write shed geom");
json.writeGeom(outputHull);
LOG.debug("done");
}
} else if (output.equals(IsoChrone.RESULT_TYPE_EDGES)) {
// in case there was no road we return only the suggested path to the street
if (noRoadNearBy) {
json.writeGeom(pathToStreet);
} else {
// -- if we would use only the edges from the paths to the origin we will miss
// some edges that will be never on the shortest path (e.g. loops/crescents).
// However, we can retrieve all edges by checking the times for each
// edge end-point
Map<ReversibleLineStringWrapper, LineString> walkShedEdges = Maps.newHashMap();
// add the walk from the pushpin to closest street point
walkShedEdges.put(new ReversibleLineStringWrapper(pathToStreet), pathToStreet);
// get the edges and edge parts within time limits
ArrayList<LineString> withinTimeEdges =
this.getLinesAndSubEdgesWithinMaxTime(
maxTime,
allConnectingEdges,
sptA,
angleLimitForUShapeDetection,
distanceToleranceForUShapeDetection,
maxUserSpeed,
usesCar,
doSpeedTest);
for (LineString ls : withinTimeEdges) {
walkShedEdges.put(new ReversibleLineStringWrapper(ls), ls);
}
Geometry mls = null;
LineString edges[] = new LineString[walkShedEdges.size()];
int k = 0;
for (LineString ls : walkShedEdges.values()) edges[k++] = ls;
LOG.debug("create multilinestring from {} geoms", edges.length);
mls = gf.createMultiLineString(edges);
LOG.debug("write geom");
json.writeGeom(mls);
LOG.debug("done");
}
} else if (output.equals("DEBUGEDGES")) {
// -- for debugging, i.e. display of detected u-shapes/crescents
ArrayList<LineString> withinTimeEdges =
this.getLinesAndSubEdgesWithinMaxTime(
maxTime,
allConnectingEdges,
sptA,
angleLimitForUShapeDetection,
distanceToleranceForUShapeDetection,
maxUserSpeed,
usesCar,
doSpeedTest);
if (this.showTooFastEdgesAsDebugGeomsANDnotUShapes) {
LOG.debug("displaying edges that are traversed too fast");
this.debugGeoms = this.tooFastTraversedEdgeGeoms;
} else {
LOG.debug("displaying detected u-shaped roads/crescents");
}
LineString edges[] = new LineString[this.debugGeoms.size()];
int k = 0;
for (Iterator iterator = debugGeoms.iterator(); iterator.hasNext(); ) {
LineString ls = (LineString) iterator.next();
edges[k] = ls;
k++;
}
Geometry mls = gf.createMultiLineString(edges);
LOG.debug("write debug geom");
json.writeGeom(mls);
LOG.debug("done");
}
} catch (org.codehaus.jettison.json.JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return sw.toString();
}