Method For Calculating The Encounter Probability In Network Space

Probabilistic time geography(PTG)can be used to measure the probability of random encounters between two moving objects.Available PTG methods are based on homogeneous space,while the network space is typically heterogeneous,which constrains individuals to the network.These constraints not only restrict the space-time accessibility of the moving objects but also affect the probability of them visiting locations or encountering other objects in space and time.Therefore,probabilistic time geography in network space must consider the geographical network on which the real motion of moving objects depends.Based on this,this paper puts forward a method for calculating the encounter probability of objects that are moving in a network by considering network constraints on movement.Firstly,this paper continues to use the continuous space encounter semantics based on the distance threshold,that is,when the distance between two moving objects does not exceed the distance threshold,the two objects meet.Secondly,the road network modeling method adopted in this paper is to build a piecewise linear reference system based on the original road network,and divide each road into multiple regular or irregular road network lengths.Such basic linear elements are called lixels.In this paper,the space time disk is used to model the spatial position of the moving object at any time in the road network,and the inverse distance weight method is used to model the possibility of the moving object at any time in the road network space.According to the characteristics of road network,network distance is used to replace Euclidean distance,and the concept of lixel weight is introduced to solve the weight assignment problem caused by irregular lixels.This paper uses the probability theory product rule and the addition rule to calculate the road network moving objects’ meeting probability based on the distance threshold.Therefore,in network space,our method improves measures of the likelihood of encounters between moving objects,thereby enabling more accurate predictions of encounter events and their probabilities.Finally,the performance of the method is experimentally evaluated.In the experiment,campus road network data and simulated trip data are used to calculate the encounter probabilities of two moving objects and to determine when and where two moving objects meet with the highest probability.On the one hand,the mathematical model of the encounter probability of moving objects in the road network is established to improve the theoretical system of time geography.On the other hand,it deepens the application of quantitative temporal geography and probability theory in motion pattern and interaction analysis of moving objects.