Worboys, M., 1994b. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37,1.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....snapshots) as regular or irregular tessellation models. On the other hand, temporality is an inherent aspect of geo information. Time is a fundamental dimension for understanding and modelling of geographic phenomena. Modelling time in GIS has been investigated [41, 22] Spatio temporal reasoning [60, 62] and reasoning about spatio temporal changes [13, 61, 38] has also become of interest. One way to incorporate the notion of time into spatial representations would be to have some combination of spatial and temporal logics. There exists a variety of spatial formalisms [14, 49, 15, 42] and a wide ....

....this goal. Traditionally, changes to geographic information (phenomenon) have been derived from a temporal reference frame. Therefore integration of time has been a long standing issue within GIS. Integration of time has been investigated from the perspective of cartography [41, 50] data models [24, 60, 47, 59] and spatial databases [5, 2] The second category of approaches has been more explicit and concerns the semantics of change [12, 13] They have focussed on the basic spatio temporal processes (viz. appearance, disappearance, transmission etc. associated with geographic entities. Closely related, ....

M. F. Worboys, `A unified model of spatial and temporal information', Computer Journal, 37(1), 26--34, (1994).

....processes based on these constraints were implemented. Even though there is a very active research area interested in the design of robust and efficient spatial databases, it is still evident the inability of current GIS regarding the implementation and management of spatial integrity constraints [14, 17]. A modification in a spatial database may cause simultaneous updates in a large number of records in multiple files, making it hard to manage all the environment. A very sophisticated control is required to avoid redundancy and loss of integrity. In the traditional database systems approach ....

Worboys, M. F. A unified model for spatial and temporal information. The Computer Journal 37(1):26-34, 1994.

....in greater detail. A comprehensive design methodology for temporal databases is needed. This methodology should be validated with actual applications. The semantics presented here can be broadened to provide a basis for real time temporal databases (cf. OS95] spatiotemporal databases (cf. Wor94] and active temporal databases. Finally, the ideas presented here and the methodology that will follow should be transitioned to existing implementation platforms, including non temporal query languages such as SQL 92 [MS93] In the short and perhaps even medium term, it is unrealistic to ....

M. F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal 37(1), 1994, pp. 27--34.

....than both. For instance in the temporal domain, interval based time models [17] were followed by TSQL2 s implicit time model [21] and pointbased time models [22, 23] SQL extensions to express spatial queries were proposed by several authors, including [8] and [9] In a seminal paper, Worboys [25] defines a spatio temporal object as a unified object which has both spatial and temporal extents, and is represented by attaching a temporal element to the components of a collection of non overlapping spatial objects that include points, straight line segments and triangular areas. This model is ....

....queries. The final two sections discuss implementation issues and the opportunities for further research. 2 The Data Model of SQL sT Many applications only use temporal information, other only use spatial infor mation, finally many use both. Therefore, following Worboys suggestion [25], we define an SOL T component that is effective at supporting temporal information, and a SOL s component that is effective at supporting spatial information; then, we combine the two representations into SOL s2 and show that this is effective in supporting spario temporal information, including ....

M.F. Worboys. A Unified Model for Spatial and Temporal Information. Computer Journal, Vol.37, No.1, pp.26-34, 1994

....predicates; in particular, we motivate why we have deliberately chosen an alternative approach. 2.1 Spatio Temporal Objects So far, only a few data models for spatio temporal data have been proposed. One approach has been to appropriately extend a spatial data model by temporal concepts. In [40] spatio temporal objects are defined as so called spatio bitemporal complexes. Their spatial features are described by simplicial complexes, and their temporal features are given by bitemporal elements attached to all components of simplicial complexes. Another approach has been to appropriately ....

M. F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37(1):25--34, 1994.

....remained two separate worlds. However, modern applications (GIS, time sequence analysis and forecasting, animation, etc. demand the efficient manipulation of spatial objects that move and or change their shapes and or size over time and involve relationships among them. For instance, Worboys [10] provides a survey of (mainly GIS oriented) spatio temporal applications on administrative areas, road networks and land ownership. Spatio temporal databases (STDBs) are SDBs in which data objects may change their spatial locations and or their shapes at different time intervals. In these ....

Worboys, M. F. (1994) A unified model for spatial and temporal information. Comput. J., 37, 26--34.

....be implemented but is somewhat more complex. A discrete model for spatio temporal objects, which builds on the abstract model in [6] is described in [4] Early research on spatio temporal databases concentrated on modeling discrete changes to the database. Examples of such models can be found in [12], 1] and [7] 1. Department of Computer Science, Norwegian University of Science and Technology, N7491 Trondheim, Norway, tossebro idi.ntnu.no 2. Praktische Informatik IV, Fernuniversitt Hagen, D 58084 Hagen, Germany, gueting fernuni hagen.de 2More recent research also addresses the dynamic ....

M. F. Worboys, A Unified Model for Spatial and Temporal Information. The Computer Journal 37:1 (1994), pp. 25-34.

....predicates; in particular, we motivate why we have deliberately chosen an alternative approach. 2.1 Spatio Temporal Objects So far, only a few data models for spatio temporal data have been proposed. One approach has been to appropriately extend a spatial data model by temporal concepts. In [41] spatio temporal objects are defined as so called spatio bitemporal complexes. Their spatial features are described by simplicial complexes, and their temporal features are given by bitemporal elements attached to all components of simplicial complexes. In [39] in a discrete snapshot model, a ....

M. F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37(1):25--34, 1994.

.... that develop database models and query languages for the description and manipulation of spatio temporal objects (Wu et al. 1997) and studies oriented to the temporal extension of current spatial data models within GIS (Langran, 1992; Cheylan and Lardon, 1993; Peuquet, 1994; Frank, 1994; Worboys, 1994; Claramunt and Thriault, 1995 and 1996) This chapter proposes a new reasoning and computational approach that integrates space and time within an integrated temporal space referential. The principles underlying temporal spaces are derived from time geography concepts, spatial and temporal ....

Worboys, M. F., 1994, A unified model of spatial and temporal information. Computer Journal, 37(1): 26-34.

....a combination of space and time in spatio temporal data models and databases . We have already discussed evolving problems and have presented a first approach for a data model in [EGSV98] A few other papers already exist that deal with the integrated modeling of space and time, for instance, Wo94,YC93] but they do not address the embedding in databases. This paper now views the topic from a rather fundamental perspective and additionally makes the following contributions: 2. We propose the database embedding of temporal objects in the spirit of the abstract data type (ADT) approach ....

M.F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, vol. 37, no. 1, pp. 27-34, 1994.

....database. We also show how to animate objects defined by parametric polygons, analyze the computational complexity of animation, and present empirical data to demonstrate the efficiency of our approach. 1 Introduction Spatiotemporal databases have recently begun to attract broader interest [10, 12, 27]. While the temporal [4, 23, 24] and spatial [14, 28] database technologies are relatively mature, their combination is far from straightforward. In this context, the constraint database approach [15] appears to be very promising. Constraint databases provide a uniform framework for modeling ....

....described in the present paper. As a result, the animation data may have to be stored on disk, significantly increasing animation time. 5 Related work Spatiotemporal data models and query languages. Spatiotemporal data models and query languages are a topic of growing interest. The paper [27] presents one of the first such models. In [10] the authors define in an abstract way moving points and regions. Apart from moving points, no other classes of concrete, database representable spatiotemporal objects are defined. In that approach continuous movement (but not growth or shrinking) can ....

[Article contains additional citation context not shown here]

M. F. Worboys. A Unified Model for Spatial and Temporal Information. Computer Journal, 37(1):26--34, 1994.

....innovation, known as MBR (Minimum Bounding Rectangle) is used to represent a region approximately as a two dimensional interval. In some recent investigations, both space and time have been treated in a unified model. For example, Worboys presents a model which allows spatio bitemporal operations [43]. Demand for the representation of a three dimensional space and objects within it has appeared because of the tremendous progress in hardware, software, and communication technology. The progress in virtual reality techniques in the last decade has been especially significant in creating this ....

M.Worboys, "A unified model for spatial and temporal information, " The Computer Journal, vol.37, no.1, pp.26-34, 1994.

....their time and space varying values. The time dimension describes when an attribute value is valid, and the spatial dimension expresses where it is valid. While each value has always a temporal evolution, it is doubtful whether it always has a spatial aspect, as discussed in Section 3.1. Worboys [Wo94] defines spatio temporal objects as so called spatio bitemporal complexes. Their spatial features are given by simplicial complexes; their temporal features are described by bitemporal elements attached to all components of simplicial complexes. In [CT95] and [PD95] event based approaches for ST ....

Worboys, M.F., A Unified Model for Spatial and Temporal Information. The Computer Journal, vol. 37, no. 1, pp. 27-34, 1994.

....of spatio temporal objects. In particular, the capability of incorporating continuous change of spatial objects over time belongs to the most challenging requirements of spatio temporal data models. In the meanwhile, some data models for spatio temporal databases have already been proposed. In (Worboys, 1994) a spatial data model has been generalized to become spatio temporal: spatio temporal objects are defined as so called spatio bitemporal complexes whose spatial features are described by simplicial complexes and whose temporal features are given by bitemporal elements attached to all components ....

Worboys, M.F. (1994) A Unified Model for Spatial and Temporal Information, The Computer Journal 37(1), 25-34.

....structures that can be used to implement attribute data types in a DBMS. Hence the paper offers a good basis for the implementation of a moving objects data blade. Earlier work on spatio temporal databases has generally been restricted to accommodate discrete changes of spatial values. Worboys [Wor94] has proposed such a model which represents spatio temporal entities as the cross product of a spatial and a temporal description, using simplicial complexes for the spatial part and sets of rectangles (for two time dimensions) for the temporal part. Other such models are [CG94] or [PD95] Some ....

M.F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37(1):25--34, 1994. 25

....papers (see, e.g. Lorentzos and Mitsopoulos 1997] for further references) This type may be used for representing time intervals as well as lengths, widths, heights, etc. From the other side, it is also possible to generalize spatial data models to become spatio temporal. The data model by Worboys [Worboys 1994] represents this approach. Here, spatial objects are associated with two temporal aspects, and a set of operators for querying is provided. However, this model does not provide an expressive type system, but basically offers only a single type, termed ST complex, with a limited set of operations. ....

Worboys, F. 1994. A unified model for spatial and temporal information. The Computer Journal 37, 1, 25--34.

....in time, and forest management systems with fire and reforestry history are some typical examples of this emerging need. Although valuable results from the research communities dealing with either spatial or temporal aspects of the aforementioned systems do exist (see for example [5] 12] [16] for the spatial requirements, and [9] 10] 11] for the temporal ones) it is only the last years that the analysis, design and implementation of applications with information varying over space and time became the new research challenge. Applications dealing with spatiotemporal information fall ....

Worboys, M., 1994. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37,1.

....routes of them, or by studying phenomena, such as a storm, which move over time, appears emerging. In the last decade, the information systems, and more specifically, the database research community, gave valuable results in modeling and retrieving, on the one hand, spatial objects [9] 15] [23], and on the other, objects in a temporal framework [10] 11] 12] 16] Some other efforts fall in the spectrum of the spatiotemporal systems, i.e. deal with combined spatial and temporal information: 17] proposes a design support environment for spatiotemporal databases focusing on the ....

....information: 17] proposes a design support environment for spatiotemporal databases focusing on the integration of time application data. 1] presents a generic model consisting of objects, states, events and conditions for explicitly representing casual links within a spatiotemporal GIS. [23] proposes a unified model for information which is referenced to two spatial dimensions and two temporal dimensions (database and event times) 6] presents a set of design patterns for spatiotemporal processes expressed in an object relationship data model. Finally, in this spectrum, domain ....

Worboys, M., 1994. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37,1.

....of spatio temporal objects. In particular, the capability of incorporating continuous change of spatial objects over time belongs to the most challenging requirements of spatio temporal data models. In the meanwhile, some data models for spatio temporal databases have already been proposed. In [30] a spatial data model has been generalized to become spatio temporal: spatio temporal objects are defined as so called spatio bitemporal complexes whose spatial features are described by simplicial complexes and whose temporal features are given by bitemporal elements attached to all components of ....

Worboys, M.F.: A Unified Model for Spatial and Temporal Information, The Computer Journal 37(1), 1994, 25-34.

....In Section 1.2 we describe criteria for designing spatio temporal query languages, and in Section 1.3 we relate spatio temporal predicates to earlier work on spatial predicates. 1.1 Spatio Temporal Data Models So far, only a few data models for spatio temporal data have been proposed. In [25] a spatial data model has been generalized to become spatio temporal. Spatiotemporal objects are defined as so called spatio bitemporal complexes whose spatial features are described by simplicial complexes and whose temporal features are given by bitemporal elements attached to all components of ....

M. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37(1):25--34, 1994.

....data models for spatio temporal data have been proposed. They all focus on describing the temporal development of single, self contained spatial objects but do not take into account collections of evolving spatial objects possibly satisfying some constraints over time. Either spatial data models [22] or temporal data models [11, 2] have been extended to become spatio temporal. The main drawback of all these approaches is that they are incapable of modeling continuous changes of spatial objects over time. Our approach to dealing with spatio temporal data supports an integrated view of space ....

M. F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37(1):25--34, 1994.

....GIS application scenarios which frequently occurred in real life projects we carried out in cooperation with industrial companies. These scenarios span a wide range of GIS problem domains and deal with features like topological (whole part) relationships, networks and object versions (see e.g. [4, 6, 9, 2, 11]) The investigation reveals that conventional RE methods like e.g. Coad Yourdon s Object Oriented Analysis (OOA) 3] are not capable to model GIS specific requirements appropriately and especially do not support the user s view sufficiently. Similar observations have been made in [7] and [10] ....

....and selling of subareas. After closing the chemical factory in parcel 3 in 1990 a pollution check exhibited the contamination 3 In recent years, much research has been devoted to temporal or spatio temporal databases in general and database models and index structures in particular (see e.g. [8, 1, 11, 5]) of the parcel, s.t. any usage will be prohibited until the year 2000. Finally, in 1995 the owner of parcel 5 bought parcel 4 and both parcels are merged into one. If we neglect all temporal aspects, GeoOOA introduced so far can be applied to the land registry example in a straightforward ....

M. Worboys. A unified model for spatial and temporal information. The Computer Journal, 37(1):26--34, 1994.

....GIS application scenarios which frequently occurred in real life projects we carried out in cooperation with industrial companies. These scenarios span a wide range of GIS problem domains and deal with features like topological (whole part) relationships, networks and object versions (see e.g. [Gut88, SV89, Tom90, CFvO93, Wor94b]) The investigation reveals that conventional RE methods like e.g. Coad Yourdon s Object Oriented Analysis (OOA) CY91] are not capable to model GIS specific requirements appropriately and especially do not support the user s view sufficiently. Similar observations have been made in [SMSE87] and ....

....prohibited for at least 10 years. Finally, in 1995 the owner of parcel 5 bought parcel 4 and both parcels are combined into one. 4 In recent years, much research has been devoted to temporal or spatio temporal databases in general and database models and index structures in particular (see e.g. [Soo91, ATSS93, Wor94b, RYG94]) FARMLAND INDUSTRIAL AREA GRASSLAND PARK POLLUTION CHECK LEGEND: YEAR 1950 YEAR 1960 1 2 3 4 1 5 YEAR 1990 1 3 5 YEAR 1995 1 3 4 5 Fig. 14. Illustrating the spatio temporal domain If we neglect all temporal aspects, GeoOOA introduced so far can be applied to the land registry example in a ....

M.F. Worboys. A unified model for spatial and temporal information. The Computer Journal, 37(1):26--34, 1994.

....and special implementation techniques have to be considered. The basis for multidimensional data representations has been already established in various approaches in the field of statistical database systems [17, 12, 6, 8, 11, 14] temporal database systems [20, 19, 18] spatial database systems [7, 16, 1, 23] and geographic information systems. There already exists one approach with respect to the application of cancer registration [21] Geocoded cancer cases are mapped to administrative units. But this approach is very restricted, it does not provide advanced statistical and geographic operators. ....

M. Worboys. A unified model of spatial and temporal information. Computer Journal, 37, 1994.

....on spatial and temporal databases does not provide much guidance in dealing with spatiotemporal phenomena. Spatial databases [9] deal with spatial objects (e.g. rectangles or polygons) and temporal databases [7] with temporal ones (e.g. intervals) Their combination can handle discrete change [8] but not continuous one, as required by applications dealing with phenomena like movement, natural disasters, or the growth of urban areas. In the latter applications, the temporal and spatial aspects cannot be conveniently separated. 2 Basic notions 2.1 Objects Definition 2.1 A spatial object ....

....closed under the operator) We will show examples of both positive and negative results. Much work remains still to be done before closure is completely characterized for various classes of spatiotemporal objects. We start by formulating in our framework a result of Worboys. Worboys framework [8] is capable of representing only discrete change. Theorem 4.1 (Polygons ; Id) is closed under intersection, union and set difference. The following new results deal with classes of spatiotemporal objects that can represent continuous change. They illustrate the difference between the closure ....

[Article contains additional citation context not shown here]

M. F. Worboys. A Unified Model for Spatial and Temporal Information. Computer Journal, 37(1):26--34, 1994.

....a major drawback of this model is its lack of generality and its heavy dependence on domain knowledge. The Video Query By Example (V QBE) system [YYHI96] is simple but only deals with the trajectory of a single moving object. A unified model for spatial and temporal information is proposed in [Wor94] A bitemporal relation, including both event time and database time, is applied to objects in the system. This model is designed for GISs. There is also some research on moving objects that result from camera motions [ABL95, SAG95] such as booming, tilting, panning, zooming etc. We do not ....

M. F. Worboys. A unified model for spatial and temporal information. The Computer Journal, 37(1):26---34, 1994.

....has led to a need for an integrated representation of geographical and historical data which corresponds as closely as possible to the way the real world changes. Although various conceptual models combining space and time have been proposed (Langran 1992, Cheylan 1993, Peuquet 1994, Frank 1994, Worboys 1994, Galton 1995) research on temporal GISs (TGIS) is still in an early stage of development. The development of TGISs requires a formal foundation comparable to the work realised for spatial models. A comprehensive framework and mathematical models of spatiotemporal relationships are needed for the ....

WORBOYS, M. F., 1994,A unified model of spatial and temporal information. Computer Journal, 37(1):26-34.

....and temporal databases does not provide much guidance in dealing with spatiotemporal phenomena. Spatial databases [Wor95] deal with spatial objects (e.g. rectangles or polygons) and temporal databases [TCG 93] with temporal ones (e.g. intervals) Their combination can handle discrete change [Wor94] but not continuous change, as required by applications dealing with phenomena like movement, natural disasters, or the growth of urban areas. In the latter applications, the temporal and spatial aspects cannot be conveniently separated. 2 Basic notions 2.1 Objects Definition 2.1 A spatial ....

....closed under the operator) We will show examples of both positive and negative results. Much work remains still to be done before closure is completely characterized for various classes of spatiotemporal objects. We start by formulating in our framework a result of Worboys. Worboys framework [Wor94] is capable of representing only discrete change. Theorem 4.1 (Polygons ; Id) is closed under intersection, union and set difference. The following new results deal with classes of spatiotemporal objects that can represent continuous change. Theorem 4.2 (Rect ; Sc Lin ) is closed under ....

[Article contains additional citation context not shown here]

M. F. Worboys. A Unified Model for Spatial and Temporal Information. Computer Journal, 37(1):26--34, 1994.

....Keywords: Spatio temporal database systems, scientific applications 1. Introduction Data Analysis of multidimensional data like spatial, temporal and statistical data occurs in a lot of scientific applications and has to be supported by modern database technology. An adequate data model [7], comfortable querying and special implementation techniques have to be considered. For this purpose we implemented our extendible approach STARS which will be evaluated in the scientific application of analyzing the spatio temporal distribution of regional health data especially of cancer data in ....

....rent in the database, access support to enable an efficient data processing to improve query response time and a descriptive SQL or OQL like query language. The basis for an integrated spatio temporal representation has been derived from various approaches in the field of temporal and spatial [6, 5, 2, 7] database systems. 2. Spatio temporal aspects Geographical informations include at least the spatial location, the shape and the relationship of complex objects with spatial aspects. The geometry description of objects is based on vector data, which is optimal supported by an object oriented ....

M. Worboys. A unified model of spatial and temporal information. Computer Journal, 37, 1994.

....translation to a constraint database with dense order constraints allows querying by Datalog, a query language which is more expressive than TQuel. In the paper we show how to enhance, through interoperability, the expressive power of the query language of the spatiotemporal data model of Worboys [Wor94] 3. Decomposability. The problem of translating between two arbitrary data models, which is hard, is decomposed into a pair of simpler problems: translating one data model to a class C of constraint databases, and then translating C to the other data model. Also, by using a common constraint ....

....of spatial objects, referring explicitly to the objects themselves. Various built in operators that work on polygons, e.g. overlap, are provided. The semantics of those languages is also point based. 2. 5 The Spatiotemporal Data Model of Worboys The spatiotemporal data model of Worboys [Wor94] is a recent example of a data model that can represent both spatial and temporal information about objects in a database. Worboys relations (our term) are 2 spaghetti relations where spatial objects are timestamped with temporal extents which can be intervals or finite unions of intervals. ....

[Article contains additional citation context not shown here]

M.F. Worboys. A Unified Model for Spatial and Temporal Information. Computer Journal, 37(1):26--34, 1994.

....a combination of space and time in spatio temporal data models and databases . We have already discussed evolving problems and have presented a first approach for a data model in [EGSV98] A few other papers already exist that deal with the integrated modeling of space and time, for instance, Wo94,YC93] but they do not address the embedding in databases. This paper now views the topic from a rather fundamental perspective and additionally makes the following contribution: 2. We propose the database embedding of temporal objects in the spirit of the abstract data type approach applied to ....

M.F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, vol. 37, pp. 27-34, 1994.

....translation to a constraint database with dense order constraints allows querying by Datalog, a query language which is more expressive than TQuel. In the paper we show how to enhance, through interoperability, the expressive power of the query language of the spatiotemporal data model of Worboys [Wor94] 3. Decomposability. The problem of translating between two arbitrary data models, which is hard, is decomposed into a pair of simpler problems: translating one data model to a class C of constraint databases, and then translating C to the other data model. Also, by using a common constraint ....

....ID x y x 0 y 0 x 00 y 00 p1 10 4 10 4 10 4 l1 5 10 9 6 9 6 l1 9 6 9 3 9 3 t1 2 3 2 7 6 3 r1 1 2 1 11 11.5 11 r1 11.5 11 11.5 2 1 2 p2 3 5 3 8 4 9 p2 4 9 7 6 3 8 p2 3 5 7 6 3 8 Table 3: Triangular Representation 2. 5 Worboys Spatiotemporal Data Model Worboys spatiotemporal data model [Wor94] is a recent example of a data model that can represent both spatial and temporal information about objects in a database. Worboys relations (our term) are 2 spaghetti relations where spatial objects are timestamped with temporal extents which can be intervals or finite unions of intervals. ....

[Article contains additional citation context not shown here]

M.F. Worboys. A Unified Model for Spatial and Temporal Information. Computer Journal, 37(1):26--34, 1994.

....in greater detail. A comprehensive design methodology for temporal databases is needed. This methodology should be validated with actual applications. The semantics presented here can be broadened to provide a basis for real time temporal databases (cf. 62] spatiotemporal databases (cf. [87]) and active temporal databases. Finally, the ideas presented here and the methodology that will follow should be transitioned to existing implementation platforms, including non temporal query languages such as SQL 92 [56] In the short and perhaps even medium term, it is unrealistic to assume ....

M. F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37(1):27--34 (1994).

....in sensitive areas with typhoon and cyclone problems, are some substantial examples of this new application area. Although in the last decade the information systems, and more specifically, the database research community gave valuable results in modeling and retrieving spatial objects [6] 11] [17], in a temporal framework [9] 12] spatiotemporal phenomena haven t really been addressed. The main reasons lie on their peculiar behavior, such as their fast evolution in space and time accompanied by the continuous change of their shape and position, involving many times fuzzy or incomplete ....

....many times fuzzy or incomplete information. These require deeper knowledge and input from the domain experts, as well as efficient tools and techniques for their representation and retrieval. Related theoretical work fall into two disjoint modeling approaches: a) eventbased [10] or object based [17]. The two have not met yet. On the other hand, domain experts give their own solutions and modeling techniques to these issues, mainly driven by the need for fast and applicable answers. The result is systems tightly coupled with specific software and hardware (see for example [1] for the use of ....

[Article contains additional citation context not shown here]

Worboys, M., 1994. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37,1.

....their time and space varying values. The time dimension describes when an attribute value is valid, and the spatial dimension expresses where it is valid. While each value has always a temporal evolution, it is doubtful whether it always has a spatial aspect, as discussed in Section 3.1. Worboys [Wo94] defines spatio temporal objects as so called spatio bitemporal complexes. Their spatial features are given by simplicial complexes; their temporal features are described by bitemporal elements attached to all components of simplicial complexes. In [CT95] and [PD95] event based approaches for ST ....

Worboys, M.F., A Unified Model for Spatial and Temporal Information. The Computer Journal, vol. 37, no. 1, pp. 27-34, 1994.

....data modeling is still a challenge (e.g. Fed93, Goo92] The early models emphasized primarily the structures to support data geometry and topology. More recently, models try to abstract features related to a given geographic area, with preponderance of object oriented proposals (e.g. PMP93, Wor94, RL95] Most models, however, are static and, furthermore do not take temporal evolution into account. Dynamic modeling is treated from a purely mathematical point of view (e.g. Fed93] without considering the existence of a database. GMOD is the result of several years working with users in ....

....with users in the area of environmental applications. It was conceived having in mind letting environmental users define their applications using concepts closer to their view of the world. It differs from the majority of the geographic data models recently proposed in the literature (e.g. Wor94, Pim95] for the following reasons: ffl it allows not only the usual static modeling, but also process and dynamic modeling, essential to implement the constraints and functions necessary to manage data evolution in georeferenced applications; ffl it supports the specification of ....

M. Worboys. A Unified Model for Spatial and Temporal Information . The Computer Journal, 37(1):26--33, 1994.

....Todays geo information systems are closed systems mainlysupporting geographic tasks in 2D space. In new spatial application areas such as environmental research, geology, city planning or telecommunications, however, a database and processing support for 3D 4D objects is required [Rap89] MJ94] Wor94] Bre96] Thus the development of object oriented 3D 4D modelling and data handling components for geo information systems is a new challenge for the spatial database community. To our knowledge, there are no comprehensive experiences with the management of 3D 4D data in ODBMS. Since 1993 our ....

M. F. Worboys. A Unified Model of Spatial and Temporal Information. Computer Journal, 37:26--34, 1994. This article was processed using the L a T E X macro package with LLNCS style

....(see, e.g. Snodgrass, 1995) have mostly been studied on parallel, but clearly separate tracks. As geophenomena are associated with both space and time, there has been a growing interest in the integration of spatial and temporal components, leading to the study of spatiotemporal databases (Worboys, 1994; Gting et al. 2000) Compared with considerable research on temporal relational databases, a smaller amount of work has been reported in the context of temporal object databases. This has similarly occurred in spatio temporal object databases. One of the important reasons has been the lack of a ....

Worboys, M., 1994, A unified model for spatial and temporal information. The Computer Journal, 37(1): 26-34.

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Worboys, M., 1994b. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37,1.

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M.F. Worboys. A unified model for spatial and temporal information. The Computer Journal, 37(1):26--34, 1994. 24

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M.F. Worboys. A Unified Model for Spatial and Temporal Information. Computer Journal, Vol.37, No.1, pp.26-34, 1994

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M. Worboys. A unified model for spatial and temporal information. The Computer Journal, 37(1):26--34, 1994.

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Michael F. Worboys. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37(1):26--34, 1994.

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M.F. Worboys. A unified model for spatial and temporal information. The Computer Journal, 37(1):26--34, 1994.

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Worboys, M., 1994. A Unified Model for Spatial and Temporal Information. The Computer Journal, 37,1.

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Worboys, M. A unified model of spatial and temporal information. Computer Journal, 1994. 37(1): p. 26-34.

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