Integrating spatio-temporal data as abstract data types into already existing data models is a promising approach to creating spatio-temporal query languages. In this context, an important new class of queries can be identified which is concerned with developments of spatial objects over time, that is, queries ask especially for changes in spatial relationships. Based on a definition of the notion of spatio-temporal predicate we provide a framework which allows to build more and more complex predicates starting with a small set of elementary ones. These predicates can be well used to characterize developments. We show how these concepts can be realized within the relational data model. In particular, we demonstrate how SQL can be extended to enable the querying of developments.

Whereas earlier work on spatio-temporal databases generally focused on geometries changing in discrete steps, the emerging area of moving objects databases supports geometries changing continuously. Two important abstractions are moving point and moving region, modeling objects for which only the time-dependent position, or also the shape and extent are relevant, respectively. Examples of the first kind of moving entity are all kinds of vehicles, aircraft, people, or animals; of the latter hurricanes, forest res, forest growth, or oil spills in the sea. The goal is to develop data models and query languages as well as DBMS implementations supporting such entities, enabling new kinds of database applications. In earlier work we have proposed an approach based on abstract data types. Hence, moving point or moving region are viewed as data types with suitable operations. For example, a moving point might be projected into the plane, yielding a curve, or a moving region be mapped to a function describing the development of its size, yielding a real-valued function. A careful design of a system of types and operations (an algebra) has been presented, emphasizing completeness, closure, consistency and genericity. This design was given at an abstract level, defining, for example, geometries in terms of infinite point sets. In the next step, a discrete model was presented, o ering nite representations and data structures for all the types of the abstract model. The present paper provides the final step towards implementation by studying and developing systematically algorithms for (a large subset of) the operations. Some of them are relatively straightforward; others are quite complex. Algorithms are meant to be used in a database context; we also address...

Recent efforts in spatial and temporal data models and database systems attempt to achieve an appropriate kind of interaction between the two areas. This paper reviews the different types of spatio-temporal data models that have been proposed in the literature as well as new theories and concepts that have emerged. It provides an overview of previous achievements within the domain and critically evaluates the various approaches through the use of a case study and the construction of a comparison framework. This comparative review is followed by a comprehensive description of the new lines of research that emanate from the latest efforts inside the spatio-temporal research community. 1

Abstract In this paper we propose a visual interface for the specification of predicates to be used in queries on spatio-temporal databases. The approach is based on a visual specification method for temporally changing spatial situations. This extends existing concepts for visual spatial query languages, which are only capable of querying static spatial situations. We outline a preliminary user interface that supports the specification on an intuitive and easily manageable level, and we describe the design of the underlying visual language. The visual notation can be used directly as a visual query interface to spatio-temporal databases, or it can provide predicate specifications that can be integrated into textual query languages leading to heterogeneous languages.

We introduce a visual language for the specification of temporally changing spatial situations. The main idea is to represent spatio-temporal (ST) objects in a two-dimensional way by their trace. The intersections of these traces with other objects are interpreted and translated into sequences of spatial and spatio-temporal predicates, called developments, that can then be used, for example, to query spatiotemporal databases. 1. ST Objects, Predicates, and Developments Spatio-temporal objects like flying airplanes, migrating whales, or spreading fires have the characteristic property that they are spatial entities changing over time and that these changes are continuous. For the modeling of these data the concept of spatio-temporal data types [1] has been

Queries about objects that change their spatial attributes over time become particularly interesting when they ask for changes in the spatial relationships between different objects. We propose a visual notation that is able to describe scenarios of changing object relationships. The visual language is based on the idea to analyze two-dimensional traces of moving objects to infer a temporal development of their mutual spatial relationships. We motivate the language design by successively simplifying object traces to their intrinsic properties. The notation can be effectively translated into a calculus of spatio-temporal predicates that formally characterizes the evolution of spatial relationships. We also outline a user interface that supports specifications by menus and a drawing editor. The visual notation can be used directly as a visual query interface to spatio-temporal databases, or it can provide predicate specifications that can be

This paper contributes a general approach to characterizing patterns of change in a spatio-temporal database. While there is a particular interest in modelling and querying how spatio-temporal entities evolve, the approach contributed by the paper is distinctive in being applicable without modification to aspatial entities as well. The paper uses the Tripod spatio-temporal model to describe and instantiate in detail the contributed approach. After briefly describing a typical application and providing basic knowledge about Tripod, the paper characterizes and classifies evolution queries and describes in detail how they are evaluated.

Integrating spatio-temporal data as abstract data types into already existing data models is a promising approach to creating spatio-temporal query languages. Based on a formal foundation presented elsewhere, we present the main aspects of an SQL-like, spatio-temporal query language, called STQL. As one of its essential features, STQL allows to query and to retrieve moving objects which describe continuous evolutions of spatial objects over time. We consider spatiotemporal operations that are particularly useful in formulating queries, such as the temporal lifting of spatial operations, the projection into space and time, selection, and aggregation. Another important class of queries is concerned with developments, which are changes of spatial relationships over time. Based on the notion of spatio-temporal predicates we provide a framework in STQL that allows a user to build more and more complex predicates starting with a small set of elementary ones. We also describe a visual notation to express developments.

Composition of temporal and spatial properties of real world objects in a unified data framework results into Moving Object Databases (MOD). MODs are able to process, manage and analyze discretely or continuously changing spatio-temporal data. This paper presents HERMES Moving Data Cartridge, which provides MOD functionality to OpenGIS-compatible state-of-theart Object-Relational DBMS. HERMES is designed to be used as a pure temporal or a pure spatial system, however, its main application is to support modeling and querying of moving objects. A relevant collection of abstract data types (ADT) and their corresponding operations are defined, developed and provided as a data cartridge extending SQL-like query languages with MOD semantics. The usefuleness of the resulting query language is demonstrated by developing an application on top of this framework, which builds and visualizes the results of a palette of spatio-temporal queries that have been proposed in the literature as an advanced Location-Based Services (LBS) benchmarking framework for the evaluation of MOD engines.

Existing spatiotemporal data models and query languages offer only basic support to query changes of data. In particular, although these systems often allow the formulation of queries that ask for changes at particular time points, they fall short of expressing queries for sequences of such changes. In this chapter we propose the concept of spatiotemporal patterns as a systematic and scalable concept to query developments of objects and their relationships. Based on our previous work on spatiotemporal predicates, we outline the design of spatiotemporal patterns as a query mechanism to characterize complex object behaviors in space and time. We will not present a fully-fledged design. Instead, we will focus on deriving constraints that will allow spatiotemporal patterns to become well-designed composable abstractions that can be smoothly integrated into spatiotemporal query languages. Spatiotemporal patterns can be applied in many different areas of science, for example, in geosciences, geophysics, meteorology, ecology, and environmental studies. Since users in these areas typically do not have extended formal computer training, it is often difficult for them to use advanced query languages. A visual notation for spatiotemporal patterns can help solving this problem. In particular, since spatial objects and their relationships have a natural graphical representation, a visual notation can express relationships in many cases implicitly where textual notations require the explicit application of operations and predicates. Based on our work on the visualization of spatiotemporal predicates, we will sketch the design of a visual language to formulate spatiotemporal patterns.