Recently there is much interest in moving objects databases, and data models and query languages have been proposed offering
data types such as
moving point and
moving region together with suitable operations. In contrast to most earlier work on spatio-temporal databases, a moving region can change
its shape and extent not only in discrete steps, but continuously. Examples of such moving regions are oil spills, forest
fires, hurricanes, schools of fish, spreads of diseases, or armies, to name but a few.
Whereas the database will contain a “temporally complete” representation of a moving region in the sense that for any instant
of time the current extent and shape can be retrieved, the original information about the object moving around in the real
world will most likely be a series of observations (“snapshots”). We consider the problem of constructing the complete moving
region representation from a series of snapshots. We assume a model where a region is represented as a set of polygons with
polygonal holes. A moving region is represented as a set of slices with disjoint time intervals, such that within each slice it is a region whose vertices move linearly with time. Snapshots
are also given as sets of polygons with polygonal holes. We develop algorithms to interpolate between two snapshots, going
from simple convex polygons to arbitrary polygons. The implementation is available on the Web.