Operators for Cell Tuple-based Spatiotemporal Data Model

A spatiotemporal data model consists of attributes or classes, operations, and consistency constraints. Various models have been proposed by the geographic information system (GIS) community. These models could not be implemented because of various reasons. One of the reasons is that these models lack completeness and remain limited to the classes. This paper discusses the dynamic operators for the object-oriented cell tuple-based spatiotemporal data model (CTSTDM). The CTSTDM and its application in urban planning were published earlier by the author. Three main classes are defined in CTSTDM (i.e., spatial, attribute, and temporal). A spatiotemporal class is the aggregation of spatial and temporal classes. A spatiotemporal class is a super class of three classes (i.e., ZeroTCellClass, OneTCellClass, and TwoTCellClass). Operators pertaining to the object of these subclasses are elaborated in this paper. Emphasis is given to TwoTCellClass. Two types of operators can be defined as the objects of these classes: static and dynamic operators. Static operators do not affect the system's state (e.g., query operators). Dynamic operators change the state of the system (e.g., create, update, or delete operators). Unlike atemporal GIS, in a temporal GIS, objects may die or be killed, but they remain in the database with a valid time stamp indicating their life span. Therefore, four dynamic operators can be distinguished in spatiotemporal databases (i.e., Create, Kill, Reincarnate, and Delete). In spatiotemporal databases, the Kill operation is different from the Delete operation, as the latter is merely a purge operation. Updating a spatiotemporal object is a complex operation. Therefore, Kill is a protected operation, while the others are public or private. An object-oriented approach and a notion of point set topology are employed to design these operators in a systematic manner. Designing these operators in this fashion may pave the way to fill the gap between concepts, design, and implementation of a generic and functional temporal GIS.