Spatial Index-based Semantic Trajectory Query And Applied Research

A similar trajectory query provides users with a way to effectively manage trajectory data so that users can specify a query area to obtain trajectory data passing through the area.Current similar trajectory query methods are often based on information such as sampling locations and sampling events.In emergencies,user travel information is often recorded in the form of text.The text cannot be directly applied to similar trajectory queries,but it contains a wealth of user travel location information.On the other hand,with the development of the Internet,there are semantic trajectory data that not only have user travel location information but also record user-specific activities in specific locations.At present,many pieces of research focus on the temporal and spatial attributes of trajectory data,but relatively few researches on the semantic activity information of trajectories.Aiming at the above two problems,this thesis proposes a text-based activity trajectory extraction method,extracts the user's travel elements from the text,and combines the road network information to restore the extraction results to obtain the user's travel trajectory;and proposes a fusion trajectory similar to activities Sexual similar trajectory query method.The main work is as follows:1.A method for extracting travel trajectories is proposed to realize the function of extracting travel elements from the text and recovering travel trajectory data.First,divide the original text according to text characteristics,extract the time information,spatial information,and travel mode;secondly,map the divided text from location name to location and time text to timestamp;finally,based on the place name address database The extraction result is restored,and the user's travel trajectory is obtained.The experimental results show that this method can effectively recover the user's activity trajectory from the text in real life.2.To support the query of the activity trajectory,a trajectory query method based on Torch optimization is proposed.Firstly,analyze the stay points in the trajectory;secondly,introduce the hash table to record the activity information of the trajectory based on the grid index;finally,design the corresponding query method based on the structure,so that the user can specify the query location,Query radius,semantic type,and activity time threshold query to obtain trajectory data with similar geographic location and semantic information.This thesis proves the effectiveness of the algorithm through experiments.3.Based on the method proposed in this thesis,a trajectory extraction application system based on travel text is designed and implemented.The system provides users with a visual interactive interface and realizes the functions of extracting travel information from travel text,restoring activity trajectory,and semantic trajectory query.