GraphHopper是否支持动态边缘权重? [英] Does GraphHopper support dynamic edge weights?

问题描述

我们正在考虑在需要进行路线规划的项目中使用它. 我们遇到的第一个问题是，我们有非常动态的变量来表示我们的体重值.这意味着我们不能使用收缩层次算法，因为每次这些变量之一更改时，我们都应该重新创建收缩"图，因此我们在考虑配置graphhopper以便不使用CH算法

We are thinking to use it in our project where we need to do a route planner. The first problem we had is that we have very dyanimc variables representing our weight values; this means that we can't use the Contraction Hierarchy algorithm becouse every time one of these variables changes we should re-create the "contracted" graph, so we were thinking to configure graphhopper in order to not use the CH algorithm

在这种情况下，是否可以修改Graphhopper代码以支持此动态边缘权重值? 例如，假设我们有节点A和节点B以及边A–B；假设该边的值为3 在我们的场景中，可能会有一个事件可以将边A–B的值从3更改为6或从3更改为2 我们可以修改代码以支持此功能吗?这取决于DataAccess的实现吗?

In this scenario is it possible to modify graphhopper code to support this dynamic edges weight values? For example let's suppose that we have node A and node B and an edge A--B; let's suppose that this edge has a value 3 In our scenario there can be an event that can modify the value of the edge A--B from 3 to 6 or from 3 to 2 Can we modify the code in order to support this feature? Is this dependant to the DataAccess implementation?

推荐答案

要修改边缘的速度或距离，您需要获取EdgeIteratorState(例如，从坐标中获取)，然后设置标记或距离.这是一个代码段:

To modify the speed or distance of an edge you need to get an EdgeIteratorState (e.g. from a coordinate) and then set the flags or distance. Here is a code snippet:

// find edge for lat,lon point
QueryResult qr = locationIndex.findClosest(lat, lon, EdgeFilter.ALL_EDGES);
if(!qr.isValid())
      throw RuntimeException("Cannot find nearby location " + lat+","+lon);
EdgeIteratorState edge = qr.getClosestEdge();
// use existing flags to reuse access information
long existingFlags = edge.getFlags();
// set speed
edge.setFlags(carFlagEncoder.setSpeed(existingFlags, newSpeed));
// set distance
edge.setDistance(newDistance);

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