[Auscope-geosciml] Composition Category [SEC=UNCLASSIFIED]

Oliver.Raymond at ga.gov.au Oliver.Raymond at ga.gov.au
Tue Aug 18 23:47:54 EDT 2009


Hi all,

Food for thought before Quebec, about the structure of the CompositionCategory attribute and the associated vocabulary...

1.  The cardinality of composition category is 0..1 on geologic units and 0..* on earth materials.  Why?  This is inconsistent, and limiting for geologic units.

                                i.            Example using the CGI vocabulary: How can I convey that a granite unit is both "Peralkaline" and "High silica chemistry", or a sedimentary unit is "Polymictic" and "Carbonate-bearing"?

                               ii.            Example using other vocabularies: How can I convey that a granite unit is "calc-alkaline", "strongly fractionated", "high K2O", and "high silica"?

Currently to do this, I have to encode an earth material associated with a unit, but that begs the question.... if I have to encode an earth material to do this, why have CompositionCategory on GeologicUnit at all?

2.  The vocabulary contains several non-exclusive composition category concepts - chemical (including specific igneous classifiers and more generic classifiers), mineralogical, and sedimentary petrological.  In a WFS, a user could not tell which of these classification systems is being used because several different classification systems are included within this one "codespace".  This also potentially leads to mixed type compositional data being delivered in a WFS within a single GeoSciML element.

I propose that:

1.  The cardinality of CompositionCategory be changed to 0..* on GeologicUnits

2.  The vocabulary be restructured into several separate vocabularies so that the classification system (ie: chemical, mineralogical, sedimentary etc) can be adequately reflected in the codespace.

          eg: something like

<gsml:compositionCategory>
    <gsml:CGI_TermValue>
        <gsml:value codeSpace="urn:cgi:classifierScheme:CGI:CompositionCategory_chemical:200811 ">carbonate chemistry</gsml:value>
    </gsml:CGI_TermValue>
</gsml:compositionCategory>

or

<gsml:compositionCategory>
    <gsml:CGI_TermValue>
        <gsml:value codeSpace="urn:cgi:classifierScheme:CGI:CompositionCategory_mineralogical:200811 ">mafic</gsml:value>
    </gsml:CGI_TermValue>
</gsml:compositionCategory>

or

<gsml:compositionCategory>
    <gsml:CGI_TermValue>
        <gsml:value codeSpace="urn:cgi:classifierScheme:GA:CompositionCategory_fractionation:2009 ">strongly fractionated</gsml:value>
    </gsml:CGI_TermValue>
</gsml:compositionCategory>

or

<gsml:compositionCategory>
    <gsml:CGI_TermValue>
        <gsml:value codeSpace="urn:cgi:classifierScheme:GA:CompositionCategory_graniteType:2009 ">A-type</gsml:value>
    </gsml:CGI_TermValue>
</gsml:compositionCategory>

Cheers,
Ollie

------------------------------------------------------------------------------------------------
Ollie Raymond
National Advice,  Maps and Standards Project
Geoscience Australia

Address: GPO Box 378, Canberra, ACT, 2601, Australia | ABN: 80 091 799 039
Ph: (02) 62499575 | Fax: (02) 62499992 | Email: Oliver.Raymond at ga.gov.au
Web:  http://www.ga.gov.au/minerals/research/national/nat_maps/nat_geol_maps.jsp<http://www.ga.gov.au/geoscience/national>

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