An Alignment of Generally Used Spatial Formats
and Description Languages with ISO 19107

by Sascha Brawer

ISO/TC 211, Working Group 7, Project 19137. Document 211 N 1459, May 2003.
PDF document, 13 pages (access restricted to ISO/TC 211)


Interoperability and transfer require a clear and unambiguous definition of the spatial aspects of geographic data. For this purpose, ISO 19107 provides a broad collection of modeling constructs. However, the very richness of ISO 19107 also means that the same situation can be described in different ways. The experience of the Joint Nordic Test Case using ISO/TC 211 standards has shown that ambiguity is not merely of theoretic concern, but that it is a real issue impeding interoperability.

The conformance clause of 19107 allows selecting a subset of the standard. In order to keep the advantage of interoperability, it is desirable that everyone perform this selection in a common way. If the selection process follows the rules of ISO 19106, the selection is called a profile. Profiles can also be subject to standardization. The purpose of this paper is to collect background information for defining a core profile of ISO 19107. Interoperability should be comparatively easy to achieve for the prospective core, since it can be assumed that its constructs are broadly implemented. Any community will be free to extend the core, thus forming a custom profile. Additional parts of ISO 19107 can be added, and it is also possible to include geometric primitives that are tailored to a very specific need.

However, it would be unrealistic to expect that custom profiles will be as widely supported as the common core. This seems to imply that the core should be rather large, to cover many different needs. But on the other hand, only a small, limited core has a chance to gain widespread acceptance. Because the set of spatial primitives heavily influences the basic algorithms that vendors need to implement, it seems rather unlikely that a broad core would be well supported. In other words, a broad core would defeat the very purpose of its existence.

The remaining part of this document analyzes spatial data formats and description languages that are currently being used within a group of nations or ISO liaison organizations. The project team for ISO 19137 has used this information for defining its working draft.