Algebraic Optimization of Combined Overlay Operations
Claus Dorenbeck and
Max Egenhofer Auto-Carto 10, Baltimore, MD,
D. Mark and D. White (eds.), pp. 296-312, March 1991.
Abstract
The operations necessary to combine map layers are formalized with
algebraic specifications. This shows that arithmetic operations
upon discrete spatial subdivisions are reduced to a single,
parametric overlay operation, the actual behavior of which is
determined by a value operation which combines the non-spatial
attributes of the individual cells of the corresponding layers. The
novel approach is the application of these formalisms to find more
efficient strategies for processing several overlay operations at
an implementation-independent level. Two particular strategies are
investigated: (1) the elimination of equivalent subexpressions to
reduce the complexity of the overlay operation and (2) the
integration of several overlay operations into a single one.
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Max Egenhofer