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Particle Aspect Ratio
This file contains the CGI Particle Aspect Ratio vocabulary, as defined by the IUGS Commission for Geoscience Information (CGI) Geoscience Terminology Working Group. AspectRatio describes the geometry of particles based on the ratios of lengths of long, intermediate and short axes of grains. Equates to sphericity in sedimentary rocks (ie: the degree to which the shape of a particle approximates a sphere). A quantitative specification is based on the ratio of lengths of long, intermediate and short axes of grain shape (Sneed and Folk, 1958; Zingg, 1935). This vocabulary includes terms for specifying average shape of some collection of particles.(eg: prolate, slightly flattened, very bladed, equant, acicular, tabular). Numeric shape values from Sneed and Folk (1958) are best understood by looking at the pictures of particles with the different shapes there and in Pettijohn et al. (1972). By extension, this vocabulary includes all concepts in this conceptScheme, as well as concepts in any previous versions of the scheme.
2009-07-14. Generate SKOS encoding of vocabulary from Excel spreadsheet.
2009-12-07 SMR Update metadata properties for version, creator, title, and format. Change skos:HistoryNote to dc:source for information on origin of terms and definitions.
2009-12-07. SMR add collections for mineralogical and sedimentary petrographic categories, improve annotation and notes on vocabulary.
2010-02-13 Add narrower relationship links by adding skos:narrower link in Protege, defining skos:narrower as inverse of skos:broader, calculating with Pellet reasoner to add inferred axioms, and using 'file/Export inferred axioms as ontology' in Protege.
2010-11-28 SMR Replace URN identifiers with http URI identifiers according to CGI URI scheme (see
2012-02-07 SMR update URI to replace numeric final token with English-language string as in original URN scheme.
2012-02-27 SMR add skos:exactMatch triples to map URIs for concepts in this vocabulary to number-token URIs in 201012 version of same concepts.
2012-11-24 SMR Update to 201211 version; add collection entity, check all pref labels are lower case, remove owl:NamedIndividual and Owl:Thing rdf:types.
2016-11-25 OLR regenerate SKOS-RDF file as part of migration to new vocabulary server. No changes to the previous 2012 version.
This file contains the 2016 SKOS-RDF version of the CGI Particle Aspect Ratio vocabulary. Compilation and review in MS Excel spreadsheet, converted to MS Excel for SKOS generation using SKOS_for_GA_from_XLS_2016.03.xslt

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