Temporal Extent for Global Change Research Databases

We propose temporal extent, a concept that can be used to produce summary or abstracted information about the values of temporal attributes in a database relation or class of objects. In its simplest form, the temporal extent is a one-dimensional interval representing the minimum and maximum time points of the instances in a class. More generally, a set of temporal intervals are used to capture the temporal coverage of a set of temporal objects or class. The summary provides information about the class in a compact form that can be used concurrently with statistical abstraction mechanisms for approximate query answering and for fast browsing.