Dear All, I have invested some time to study the OpenGIS specifications, in order to see, if the CIDOC CRM can learn something from them, but also to estimate what it would mean to feed data from CRM form to GIS applications.
I started this exercise as a mapping, but finally only a very small part can be mapped formally, not enough to make sense by itself. The reason is, that OpenGIS is mainly on another level. On one side, it invests a lot in encoding and transformation semantics, using mathematical geometric abstractions, on the other side it foresees encoding of semantic information in the sense of the CRM, but without declaring any such information, besides an "underspecified" concept of "Feature". The way OpenGIS defines and deals with semantic information seems to be completely compatible with the CRM, as well as the way the CRM deals with measures seems to be completely compatible with OpenGIS, except for accuracy handling. So: Spatiotemporal topological operators as primary information like "overlaps with", "borders with", "before" "after" etc. we have to find from other sources, if we regard them as necessary. They are quite well within the scope of OpenGIS, so OpenGIS could make use of them, as well as of more elaborate "feature types". The actuall overlap is in the relation between Place and Place Appellation, where OpenGIS is compatible with the CRM, of course by far more detailed. Similarly the notion of "measure" is compatible with CRM "Dimension". The notion of time is more poorly defined in OpenGIS, and not completely consistent throughout their documentation. Accuracy handling in OpenGIS is solely based on statistical error models, and solely based on interval arithmetic in the CRM. Both approaches make sense and there are sound models how to relate both. As the CRM is not made for computation-intensive reasoning, interval arithmetic is the better solution.Besides that, historical data produce indeterminacy intervals rather than statistical errors. To my opinion, OpenGIS should be dealing with both. There could be a working group elaborating specifications about how cultural data could be interfaced with OpenGIS. See my report: http://cidoc.ics.forth.gr/crm_documents.html http://cidoc.ics.forth.gr/docs/opengis_map.doc -- -------------------------------------------------------------- Dr. Martin Doerr | Vox:+30(81)391625 | Senior Researcher | Fax:+30(81)391609 | Project Leader SIS | Email: [email protected] | | Centre for Cultural Informatics | Information Systems Laboratory | Institute of Computer Science | Foundation for Research and Technology - Hellas (FORTH) | | Vassilika Vouton,P.O.Box1385,GR71110 Heraklion,Crete,Greece | | Web-site: http://www.ics.forth.gr/proj/isst | --------------------------------------------------------------
