《交通地理信息系统》-矢量数据模型综述

Vector Data Model:A Literature ReviewAuthor:Qianni WangStudent number:20151129561.INTRODUCTIONThe vector data model is a strategy for describing distinct features in GIS.In order to have abetter understanding of the vector data model,we read the literature and find the introductionon the website.Through the integration of these materials,we can easily understand what thevector data model is and the usage of the vector data model,the development and the featuresof the vector data model.The vector data model is an important concept in the GIS system sowhen we truly understand it,we will have an opportunity to improve the weakness of currentmodels and to promote the development of Geographic data processing.2.REVIEW2.1 Data Model in GISThe vector data model is one of the two main types of GIS data models,so we should learndata model before deeply understand of the vector data model.2.1.1 The definition of data modelA data model in GIS system is a mathematical construct to represent geographic objectsor surfaces as data.It contains two types of information which are the attribute informationand spatial information that constitute a geologic map.A data model may be highly conceptual,or it may describe the data structure for managing information within a specific hardware orsoftware platform.(1)In either case,it is a central construct because it addresses the databasedesign for geologic maps in GIS format.There are two types of data models which are widely used in GIS software,the raster datamodel and the vector data model(2).We can zoom the pictures to distinct two types of model,if the edge is still crisp,it might be the vector data model.2.1.2 Raster data modelThe raster data model represents data using a grid of cells.And the rectangles andsquares cells are usually used as raster girds(3).There is only one value in every cell which canbe used to interpret to mean several different things.The raster models are usual for storingcontinuous da (4)ta,so it is widely used to describe the ocean,vegetation and animaldistribution (5).2.1.3 Vector data modelThe vector data model represents data using the collection of points,lines,and polygons(6).Through 0 dimensional,1 dimensional,2 dimensional methods,objects located on theground can be easily described.Although there are many relationships between differentcomponents to describe how those are joined,all vector data fundamentally consists of lists ofco-ordinates.The vector models are useful for storing data that has discrete boundaries,suchas country borders,land parcels,and streets(7).2.1.4 Vector-Advantages and disadvantagesThere are many differences between the vector data model and the raster data model.So