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Nowadays the distribution of topographic data, especially the propagation of geographical updates toward topographical databases, is still a methodological and technical problem to address in the context of large applications with many different users. The increment distribution method is becoming the primary way for distributing updates information of topographical database. In this case, the producer of the data has to identify geographical changes in order to generate relevant increment. In order to clearly classify and describe all kinds of changes and corresponding data delta (i.e. increment), we propose a new conceptual model of changes based on the explicit description of state transformation of geographical entities in the real world and state transformation of geographical objects in the data world. Such model is not only closest to the modeling of the real world change processes but also is easy to identity the data delta resulted from the change process. The basis for tracing these changes is the concept of state transformation of geographical entities and objects. The state transformation of a geographical entity is described with an event (such as merge, split, appearance etc.). The state transformation of object is described with an operation in the data world (such as creation, deletion etc.). Based on a small set of primitives relating to the event types and operation types of objects, we model the semantics and data delta associated with change. The distribution of increment of the Chinese residential data in topographical database is used here as a case study.
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