Isochrone calculation - node out of bound

Open Source Routing Engine Isochrone
1

I am attempting to run an Isochrone calculation to find all nodes within a time limit of a lat/long. I am getting an error when I give a limit limit longer than a few seconds - presumably because the original lat/long point is appearing in the output of the ShortestPathTree?

I am running a local install of com.graphhopper:graphhopper-core:7.0-pre1 in a Databricks notebook.

For reference, the BaseGraph has 6023015 nodes

My code is as follows:

import com.graphhopper._

import com.graphhopper.config.Profile

import com.graphhopper.config.CHProfile

import com.graphhopper.isochrone.algorithm.ShortestPathTree;

import com.graphhopper.routing.ev.Subnetwork;

import com.graphhopper.routing.querygraph.QueryGraph;

import com.graphhopper.routing.util.DefaultSnapFilter;

import com.graphhopper.routing.util.EncodingManager;

import com.graphhopper.routing.util.TraversalMode;

import com.graphhopper.routing.weighting.Weighting;

import com.graphhopper.storage.index.Snap;

import com.graphhopper.util.GHUtility;

import com.graphhopper.util.PMap;

import java.util.concurrent.atomic.AtomicInteger;

val hopper = new GraphHopper()

hopper.setGraphHopperLocation("[path to cache of PBF road network data]")

hopper.setAllowWrites(false)

hopper.setProfiles(

new Profile("car").setVehicle("car").setWeighting("fastest").setTurnCosts(true)

)

hopper.getCHPreparationHandler().setCHProfiles(

new CHProfile("car")

)

hopper.load()

val encodingManager = hopper.getEncodingManager()

val weighting = hopper.createWeighting(hopper.getProfile("car"), new PMap())

val snap = hopper.getLocationIndex().findClosest(51.501012, -0.126129, new DefaultSnapFilter(weighting, encodingManager.getBooleanEncodedValue(Subnetwork.key("car"))))

val queryGraph = QueryGraph.create(hopper.getBaseGraph(), snap)

===

val tree = new ShortestPathTree(queryGraph, weighting, false, TraversalMode.EDGE_BASED)
tree.setTimeLimit(1*60*1000)

// loop over shortest path tree to see nodes within time limit and total count
val counter = new AtomicInteger(0)

// Initialize empty lists to hold the results
val nodes = scala.collection.mutable.ListBuffer[Int]()
val times = scala.collection.mutable.ListBuffer[Double]()
val distances = scala.collection.mutable.ListBuffer[Double]()

val lons = scala.collection.mutable.ListBuffer[Double]()
val lats = scala.collection.mutable.ListBuffer[Double]()

val speed = 0.0

tree.search(snap.getClosestNode(), label => {

    //counter.incrementAndGet()

    nodes += label.node                // Add node to the nodes list
    times += label.time / 60.0 / 1000.0               // Add time to the times list (ms to minutes)
    distances += label.distance / 1609.34        // Add distance to the distances list (metres to miles)

    val speed = distances.last / times.last * 60.0 // miles per min to miles per hour

    lons += queryGraph.getNodeAccess().getLon(label.node)
    lats += queryGraph.getNodeAccess().getLat(label.node)

    println(s"Node: ${label.node}, Time: ${times.last}, Distance: ${distances.last}, Lat: ${lats.last}, Lon: ${lons.last}, Spd: ${speed}")

  
})
println(s"Total nodes found: ${counter.get()}")

====

The latter fails to execute with the error: “IllegalArgumentException: node: 6023015 out of bounds [0,6023015[”

Could anyone advise on how to solve this problem?

Thanks