Array, ArrayType, Bag, BagType

Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. 395 element name=Array type=gml:ArrayType substitutionGroup=gml:AbstractGML complexType name=ArrayType complexContent extension base=gml:AbstractGMLType sequence element ref=gml:members minOccurs=0 sequence extension complexContent complexType

I.2.8 metaDataProperty, MetaDataPropertyType, AbstractMetaData, AbstractMetaDataType

The schema components specified in this subclause are superseded by the schema components specified in 7.2.6. This property contains or refers to a metadata package that contains metadata properties in an encoding used in a previous version of GML. This element has been deprecated and is superseded by elements whose content model is derived from gml:AbstractMetadataPropertyType. More detail is provided in 7.2.6. element name=metaDataProperty type=gml:MetaDataPropertyType complexType name=MetaDataPropertyType sequence minOccurs=0 element ref=gml:AbstractMetaData sequence attributeGroup ref=gml:AssociationAttributeGroup attribute name=about type=anyURI complexType The optional “about” attribute carries a URI which points to an element or range of elements, or other resource to which this metadata refers. The value of the metaDataProperty is an abstract element gml:AbstractMetaData that acts as a placeholder for “any package of metadata properties”, defined as follows: element name=AbstractMetaData type=gml:AbstractMetaDataType abstract=true substitutionGroup=gml:AbstractObject complexType name=AbstractMetaDataType abstract=true mixed=true sequence attribute ref=gml:id complexType

I.2.9 GenericMetaData, GenericMetaDataType

For convenience, a generic concrete MetaData element was provided in a previous version of GML. This element has been deprecated and is superseded by the schema components specified in 7.2.6. element name=GenericMetaData type=gml:GenericMetaDataType substitutionGroup=gml:AbstractMetaData complexType name=GenericMetaDataType mixed=true complexContent mixed=true extension base=gml:AbstractMetaDataType sequence any processContents=lax minOccurs=0 maxOccurs=unbounded sequence extension complexContent 396 Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. complexType

I.3 Basic types, Null

gml:Null is superseded by nillable and nilReason attributes as specified in 8.2.3.2. The gml:Null element was declared as follows: element name=Null type=gml:NilReasonType EXAMPLE This element might appear in data instance documents as follows: gml:Nullwithheldgml:Null gml:Nullhttp:my.big.orgexplanationstheDogAteItgml:Null The first example uses one of the built-in values for Null. The second example contains a reference to an explanation available elsewhere, identified by a URI. The purpose in providing the gml:Null element was as follows: In order to construct a content model where a value may be omitted, the cardinality constraint expressed in XML Schema using the construction minOccurs=”0” might be used. However, this approach carries the risk that the reason for the value not being present may be misinterpreted. As an alternative the element gml:Null may be included as a member of a choice group, alongside an element of the data type of a “normal” value. EXAMPLE The content model described by the schema fragment element name=footprint complexType choice element ref=gml:Envelope element ref=gml:Null choice complexType element allows either of the following data instances to be valid: footprint gml:Envelope … gml:Envelope footprint footprint gml:Nullinapplicablegml:Null footprint This allows the hypothetical element “footprint” to appear in an instance document, optionally containing an explicit marker indicate why it has no value, instead of having semantics inferred from the absence of a value.

I.4 Features

I.4.1 location, LocationPropertyType, LocationKeyWord, LocationString

The gml:location element was a convenience property that described the generalized location of the feature. It was defined as follows: