Geographic Information Systems: An Introduction, 3rd Edition

11.8 Logical Consistency

ISO (2001) has proposed that logical consistency should comprise the following elements:

1. Conceptual consistency—adherence to rules of conceptual schema
2. Domain consistency—adherence of values to the value domains
3. Format consistency—degree to which data is stored in accordance with the physical structure of the data set
4. Topological consistency—correctness of the explicitly encoded topological characteristics of a data set

The abstract description of the real world features is called a data model or a conceptual model. A conceptual model described using a conceptual schema language (e.g. UML, EXPRESS, IDEF1x) is called a conceptual schema. Conceptual consistency thus includes adherence to the rules of the conceptual schema. This means that it should be stated when elements in a database are established on the basis of new rules, for example, new relations, as compared with what is specified in the data model/conceptual schema.

Domain consistency requires adherence of values to the value domain. This means that it should be stated if any of the data have values that exceed the specified value limits—for example, that an object type has a specified accuracy of +/− 1m, whereas some objects are registered with +/− 10m; or that permitted values are to lie within the area of 50 to 100, whereas some objects are registered with the values of 40 and 110.

Format consistency requires the data sets to be stored in accordance with the physical structure or the format ...