VehicleStream

1、Vehicle StreamMapStream ProcessorQuery ProcessorStream GeneratorHAT.View ManagerService Agent.Service Agent.View1HAT的结构中间节点（区域）和叶节点（路段）struct HATNode point LeftLow; point RightUp; int aggregation; HATNode *Child; int ChildNum; Segments *Seg; int SegNum; int level; struct Segments point Start; point

2、End; int aggregation;2HAT的生成Generating Multiple Granularity TreePartition the whole map into districts(regions) not intersecting(ensuring that one route segment may not be contained in two districts). The root of MGT corresponds to the map, and each district a child node.If needed, partition the dis

3、tricts into sub-districts recursively, and add corresponding child nodes into MGT.For each node of the lowest level(leaf node), the route segments in the district represented by the node are placed into it.For quick retrieval, route segments in a leaf node are organized using the 2-dimensional case

4、of Segment Tree.In the MGT, any route segment can be found quickly3HAT的生成(2)Generating Hierarchy Aggregation TreeAt a certain time, with location information of all vehicles, associate them with different route segments.Calculate the aggregation on each route segment and store the result into corres

5、ponding node.If the aggregation of a district is required, make aggregation on the aggregations of route segments in it. 4视图的结构视图中涉及的区域是包含在参考域中的所有区域，以及与参考域相交的最小粒度区域，所以视图并不是HAT的子树，是由代表上述区域的节点组成的。参考域起点终点5Assume V is the root of viewGiven the current location and the destination, let R represents the region determined by the two positions:1. For a district D contained in R, insert the sub-tree rooted by D into proper level of V;2. For a district