[auscope-geosciml] FW: MappedFeature [SEC=UNCLASSIFIED]

Sen, Marcus A. mase at bgs.ac.uk
Fri May 27 04:00:09 EDT 2011


> -----Original Message-----
> From: auscope-geosciml-bounces at lists.arcs.org.au [mailto:auscope-
> geosciml-bounces at lists.arcs.org.au] On Behalf Of
> Bruce.Simons at dpi.vic.gov.au
> Sent: 27 May 2011 02:33

> I think the GeoSciML Designers would agree with Clemens' observations.
> However, GeoSciML has (mostly) been designed as an implementation (ie
> physical) information model, not a conceptual or logical model. As such
> GeoSciML is really the schema, not the schema's visual representation
> (the UML). The Design team have agreed that to maximise
> interoperability, properties should be mandatory where it is sensible
> for them to be logically expected.  Due to poorly populated legacy
> datasets often these properties need to be nillable.
I don't follow why you say "However"? The example you give of poorly populated legacy datasets seems to accord with the reasons for representing two different kinds of "no data" in the INSPIRE General Conceptual Model as quoted by Michael Lutz: " The characteristic is not present or not applicable in the real world *or* the characteristic is not present in the spatial object, but may be present or applicable in the real world." (My emphasis as I think that is the *or* between the two no data types.) So we are using nillable where some property isn't present in our spatial objects ("poorly populated") but is applicable in the real world ("logically expected").

> Nillable therefore needs to remain as a tagged value.  Whether we also
> want to maintain the overhead of either <<voidable>> or UML notes is a
> documentation question.
I don't have any particular opinion on the solution but I can't see a relevant difference between GeoSciML and INSPIRE here. (Michael Lutz comment that "You can automatically apply default values of tagged values associated with a stereotype to UML elements carrying the stereotype in EA." does sound worth investigating, however.)

Marcus


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