Graphhopper：当图形具有无效边界时无法创建位置索引

Question

我在我的 java 项目中通过 maven 使用 graphhopper 0.8。我用以下代码创建了一个网络

FlagEncoder encoder = new CarFlagEncoder();
EncodingManager em = new EncodingManager(encoder);

// Creating and saving the graph
GraphBuilder gb = new GraphBuilder(em).
    setLocation(testDir).
    setStore(true).
    setCHGraph(new FastestWeighting(encoder));
GraphHopperStorage graph = gb.create();

for (Node node : ALL NODES OF MY NETWORK) {
    graph.getNodeAccess().setNode(uniqueNodeId, nodeX, nodeY);
}

for (Link link : ALL LINKS OF MY NETWORK) {
    EdgeIteratorState edge = graph.edge(fromNodeId, toNodeId);
    edge.setDistance(linkLength);
    edge.setFlags(encoder.setProperties(linkSpeedInMeterPerSecond * 3.6, true, false));
}

Weighting weighting = new FastestWeighting(encoder);
PrepareContractionHierarchies pch = new PrepareContractionHierarchies(graph.getDirectory(), graph, graph.getGraph(CHGraph.class), weighting, TraversalMode.NODE_BASED);
pch.doWork();

graph.flush();

LocationIndex index = new LocationIndexTree(graph.getBaseGraph(), graph.getDirectory());
index.prepareIndex();
index.flush();

此时，图中保存的边界框显示了正确的数字。文件被写入磁盘，包括 "location_index"。但是，重新加载数据会出现以下错误

Exception in thread "main" java.lang.IllegalStateException: Cannot create location index when graph has invalid bounds: 1.7976931348623157E308,1.7976931348623157E308,1.7976931348623157E308,1.7976931348623157E308
at com.graphhopper.storage.index.LocationIndexTree.prepareAlgo(LocationIndexTree.java:132)
at com.graphhopper.storage.index.LocationIndexTree.prepareIndex(LocationIndexTree.java:287)

读取是用下面的代码完成的

FlagEncoder encoder = new CarFlagEncoder();
EncodingManager em = new EncodingManager(encoder);

GraphBuilder gb = new GraphBuilder(em).
            setLocation(testDir).
            setStore(true).
            setCHGraph(new FastestWeighting(encoder));

// Load and use the graph
GraphHopperStorage graph = gb.load();

// Load the index
LocationIndex index = new LocationIndexTree(graph.getBaseGraph(), graph.getDirectory());
if (!index.loadExisting()) {
    index.prepareIndex();
}

所以 LocationIndexTree.loadExisting 运行正常，直到进入 prepareAlgo。此时，图形已加载。但是，边界框没有设置并保持默认值？！读取位置索引不会更新边界框。因此，错误下游。我究竟做错了什么？首先如何保留边界框？如何重建bbox？

Answer 1

TL;DR 不要使用笛卡尔坐标，而是坚持使用 OSM 使用的 WGS84。

笛卡尔坐标系，例如EPSG:25832可能有百万范围内的坐标。在执行一些数学运算后，坐标的幅度可能会进一步增加。最终，Graphhopper 会将坐标存储为整数。也就是说，所有的坐标可能最终都是Integer.MAX_VALUE。因此，边界框无效。

Graphhopper：当图形具有无效边界时无法创建位置索引

Graphhopper: Cannot create location index when graph has invalid bounds

graphhopper