Value element hierarchy Value objects schema

Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. 185  Schemas which need values may use the abstract element gml:AbstractValue in a content model in order to permit any of the gml:AbstractScalarValues, gml:AbstractScalarValueLists, gml:CompositeValue or gml:ValueExtent to occur in an instance, or the named group gml:Value to also permit gml:AbstractTimeObjects, gml:AbstractGeometrys, and gml:Nulls deprecated.

16.4.3 Boolean, BooleanList

For recording a value or list of values from two-valued logic, using the XML Schema boolean type; these elements use the following schema declarations: element name=Boolean substitutionGroup=gml:AbstractScalarValue nillable=true complexType simpleContent extension base=boolean attribute name=nilReason type=gml:NilReasonType extension simpleContent complexType element element name=BooleanList type=gml:booleanOrNilReasonList substitutionGroup=gml:AbstractScalarValueList gml:booleanOrNilReasonList is described in 8.2.4.1. EXAMPLE In an instance the following examples may be found: gml:Boolean1gml:Boolean gml:Booleanfalsegml:Boolean gml:Boolean xsi:nil=‖true‖ nilReason=‖missing‖ gml:BooleanList1 missing 0 1 1 http:my.big.orgexplanationstheDogAteIt 0 1gml:BooleanList NOTE These examples illustrate the use of the various Boolean values {1, 0, true, false} and also the fact that nilReason values such as ―missing‖ or a URI may be embedded within a list.

16.4.4 Category, CategoryList

For recording terms representing a classification. These elements use the following schema declarations: element name=Category substitutionGroup=gml:AbstractScalarValue nillable=true complexType simpleContent extension base=gml:CodeType attribute name=nilReason type=gml:NilReasonType extension simpleContent complexType element element name=CategoryList type=gml:CodeOrNilReasonListType substitutionGroup=gml:AbstractScalarValueList A gml:Category has an optional XML attribute codeSpace, whose value is a URI which identifies a dictionary, codelist or authority for the term. EXAMPLE In an instance the following examples may be found: 186 Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. gml:Categorygoodgml:Category gml:Category xsi:nil=‖true‖ nilReason=‖missing‖ gml:Category codeSpace=http:my.big.orgdictionariesrocktypesSyenitegml:Category gml:CategoryList codeSpace=http:my.big.orgdictionariesrocktypesSyenite Granite missing Tuffgml:CategoryList gml:CategoryList codeSpace=―http:my.big.orgspecies―bettong numbat phasogale wallaby possum gml:CategoryList

16.4.5 Count, CountList

For recording integers representing a rate of occurrence. These elements use the following schema declarations: element name=Count substitutionGroup=gml:AbstractScalarValue nillable=true complexType simpleContent extension base=integer attribute name=nilReason type=gml:NilReasonType extension simpleContent complexType element element name=CountList type=gml:integerOrNilReasonList substitutionGroup=gml:AbstractScalarValueList EXAMPLE In an instance the following examples may be found: gml:Count513gml:Count gml:Count xsi:nil=‖true‖ nilReason=‖missing‖ gml:CountList34 56 2 inapplicable 153gml:CountList

16.4.6 Quantity, QuantityList

For recording numeric values with a scale. The content of the element is an amount using the XML Schema type double which permits decimal or scientific notation. These elements use the following schema declarations: element name=Quantity substitutionGroup=gml:AbstractScalarValue nillable=true complexType simpleContent extension base=gml:MeasureType attribute name=nilReason type=gml:NilReasonType extension simpleContent complexType element element name=QuantityList type=gml:MeasureOrNilReasonListType substitutionGroup=gml:AbstractScalarValueList An XML attribute uom ―unit of measure‖ is required, whose value is a URI which identifies the definition of a ratio scale or units by which the numeric value shall be multiplied, or an interval or position scale on which the value occurs. EXAMPLE In an instance the following examples may be found: gml:Quantity uom=m4.32e-4gml:Quantity gml:Quantity xsi:nil=‖true‖ nilReason=‖withheld‖