A visual language for the evolution of spatial relationships and its translation into a spatio-temporal calculus

Abstract

IntroductionStimulated by the deep relationships between temporal and spatial data there has recently been an increasing interest in integrating database support for both kinds of data and in designing spatio-temporal databases. Spatio-temporal databases deal with spatial objects that change over time (for example, they move, they grow, or they alter their shape): cars, planes, people, animals, ..., storms, lakes, forests, etc. Hence, database systems, in particular, spatial and temporal database systems, and geographical information systems (GIS) need to be appropriately extended to handle this kind of information. Of particular interest is, of course, the development of simple but powerful query languages that allow one to ask for changes in spatial relationships, for instance: "Has a tornado ever crossed Iowa?" or "Which planes were able to avoid a certain blizzard?". A formal foundation for these kinds of queries is given by the concept of spatio-temporal predicates [16]. Whereas it is possible to identify a relatively small set of spatial predicates [10], it is almost impossible to do so in the spatio-temporal case, simply because there are too many of them. Thus, there is a very strong need for a simple way of specifying spatio-temporal situations, and a visual notation can be extremely helpful here. This paper continues our previous work [15,17] aiming at proposing a visual language for spatio-temporal predicates. The main idea is to graphically represent the temporally changing evolution of a spatio-temporal object (like a

Representing moving objects in computer-based expert systems: the overtake event example

“…However, the goal of these proposals is mainly to facilitate queries on video databases and not the querying of spatio-temporal databases. For example, Erwig and Schneider (2003) present a visual notation that is able to describe scenarios of changes in the topological relationships between different objects. A possible avenue for future work would be to extend these topological relationships with the expressiveness afforded by QTC relations.…”

Moving GeoPQL: a pictorial language towards spatio-temporal queries

“…Spatial query languages that followed this approach are Sketch! [27] Spatial-Query-By-Sketch [5,11], VISCO [38], GeoPQL [16] and, finally, the language proposed by Erwig and Schneider [15].…”

Toward Spatio-Temporal Patterns

“…In [26] the design of the visual language is motivated in detail and a user interface is defined. The visual notation is generalized to deal with undefined parts of object developments in [29]. That paper also defines the translation into our formal model of spatiotemporal predicates.…”

“…An example is shown in Figure 1.2 that specifies the Leaves predicate. (The interpretation of pictures like these and their formal translation into spatiotemporal predicates is described in detail in [29].) Additional improvements and simplifications can be achieved by embedding the query notation in a tailor-made user interface that supports the creation and adaptation of queries by direct manipulation of the objects whose relationships represent spatiotemporal predicates and patterns [26].…”