A visual language for the evolution of spatial relationships and its translation into a spatio-temporal calculus
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 integrated into textual query languages leading to heterogeneous languages.
translation object traces visual predicate specification visual database interface spatio-temporal queries