Research On Database Management And Spatiotemporal Analysis Of Vector Tile Map

Vector tile map is a new trend in the development of Internet maps.It has the characteristics of high map cutting efficiency,fast rendering speed,low space occupation,and dynamically adjustable style.However,the vector tile map still adopts the tile file management method,which cannot perform advanced management and access to the map's vector tiles.In addition,vector tile maps are mainly for browsing and display,and lack of visualization and analysis of spatial and temporal state of geographical elements,cannot reveal the differences of the same geographic element in different time states,and cannot analyze the development and evolution of each geographic element.In response to the above problems,this thesis proposes a database management and spatiotemporal analysis method for vector tile maps,which mainly includes three aspects:(1)detection and expression of the changing relationship of geographic elements;(2)Research on database management methods;(3)Research on spatiotemporal analysis methods of vector tile maps.The details are as follows:(1)Firstly,by analyzing the changes of geographic elements in vector data,the changes of geographic elements are divided into four types: elements increase,attribute changes,graphics changes and element reduction,detecting and determining the change type of geographic elements from two aspects of attribute change and graphic change.Then,different change detection algorithms are designed for three kinds of vector data of point,line and shape to realize the extraction of the changing relationship of vector data.Next,based on the classification of the change relationship of geographical elements,design the relational database model and structure of the vector data change library,and realize the storage and management of the change relationship of the vector data.Finally,based on the change detection algorithm and change library of vector data,we propose the processing flow of vector data change detection and develop the corresponding system prototype to realize the automatic identification,extraction and analysis of the change relationship of geographical elements in different phases,and manage and construct a set of change relationships of vector data.(2)Considering a large amount of tile data,unstructured data and hierarchical file structure of vector tile maps,and the difficulty of tile data storage and management in vector tile maps,we propose a specific solution for vector tile map management using document-type No SQL database Mongo DB.First,we designed the database structure of the vector tile map library according to the document data model of Mongo DB.Then,we use the distributed architecture of Mongo DB to build a cluster management method consisting of multiple storage nodes to achieve fragmented storage and efficient query of vector tile data.Finally,we use the API interface of Mongo DB to develop a system module for the storage of vector tile data to realize the automatic storage of massive tile data.(3)Based on the vector data change library and the vector tile map library,we study the temporal and spatial evolution process of geographic elements from two levels of elements and regions.Firstly,by combining the vector tile map with the spatial-temporal evolution method of geographic elements,we propose the extraction method and process for the element evolution and regional evolution of the vector tile map;Secondly,using the feature that the vector tile map style can be dynamically configured,different map styles are used to render the changed elements according to the change relationship of the extracted elements,such as elements increase,elements changes,and elements reduction,to realize the visualization of the time-space evolution process;Finally,with Mapbox as the web front-end map engine,we designed and developed a prototype of the vector tile map spatiotemporal evolution analysis system,which conducts an online visual analysis of the change relationship of geographic elements on the Web site to reveal the historical changes and evolution of geographic elements.Based on the above research,this thesis collects and sorts out the vector data of Jinan for five years in 2011,2014,2017,2019,and 2021,and obtains the element change relationship between each phase data through the change detection system.The Geo Server map server generates the corresponding vector tile map,realizes the unified management of tile data through the Mongo DB storage system module,and finally visualizes the spatial and temporal evolution relationship of geographic elements in the vector tile map spatiotemporal evolution analysis system.The experimental results show that the method proposed in this thesis can support the management and online visual analysis of massive vector tile map data,and can promote and apply on the municipal or provincial Internet map platform.