The MLPQ/GIS constraint database system

MLPQ/GIS [4,6] is a constraint database [5] system like CCUBE [1] and DEDALE [3] but with a special emphases on spatio-temporal data. Features include data entry tools (first four icons in Fig. 1), icon-based queries such as @@@@ Intersection, @@@@ Union, @@@@ Area, @@@@ Buffer, @@@@ Max and @@@@ Min, which optimize linear objective functions, and @@@@ for Datalog queries. For example, in Fig. 1 we loaded and displayed a constraint database that represents the midwest United States and loaded two contraint relations describing the movements of two persons. The query icon opened a dialog box into which we entered the query which finds (t, i) pairs such that the two people are in the same state i at the same time t.MLPQ/GIS can animate [2] spatio-temporal objects that are linear constraint relations over and t.Users can also display in discrete color zones (isometric maps) any spatially distributed variable z that is a linear function and For example, Fig. 2 shows the mean annual air temperature Nebraska. Animation and isometric map display can be combined.