Object Fusion in Geographic Information Systems

Given two geographic databases, a fusion algo- rithm should produce all pairs of correspond- ing objects (i.e., objects that represent the same real-world entity). Four fusion algo- rithms, which only use locations of objects, are described and their performance is mea- sured in terms of recall and precision. These algorithms are designed to work even when lo- cations are imprecise and each database rep- resents only some of the real-world entities. Results of extensive experimentation are pre- sented and discussed. The tests show that the performance depends on the density of the data sources and the degree of overlap among them. All four algorithms are much better than the current state of the art (i.e., the one- sided nearest-neighbor join). One of these four algorithms is best in all cases, at a cost of a small increase in the running time compared to the other algorithms.