The Temporal Reference Systems schema for GML 3.1 provides constructs for handling various styles of temporal reference system.
This schema reflects a partial implementation of the model described in ISO 19108:2002.
GML is an OGC Standard.
Copyright (c) 2001,2005,2010 Open Geospatial Consortium.
To obtain additional rights of use, visit http://www.opengeospatial.org/legal/ .
Properties
attribute form default:
unqualified
element form default:
qualified
version:
3.1.1.2
Element gml:_TimeReferenceSystem
Namespace
http://www.opengis.net/gml
Annotations
Abstract element serves primarily as the head of a substitution group for temporal reference systems.
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<element name="_TimeReferenceSystem" type="gml:AbstractTimeReferenceSystemType" abstract="true" substitutionGroup="gml:Definition"><annotation><documentation>Abstract element serves primarily as the head of a substitution group for temporal reference systems.</documentation></annotation></element>
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
An Era may be composed of several member Eras. The "member" element implements the association to the Era at the next level
down the hierarchy. "member" follows the standard GML property pattern whereby its (complex) value may be either described
fully inline, or may be the target of a link carried on the member element and described fully elsewhere, either in the same
document or from another service.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
<element name="member" type="gml:TimeOrdinalEraPropertyType" minOccurs="0" maxOccurs="unbounded"><annotation><documentation>An Era may be composed of several member Eras. The "member" element implements the association to the Era at the next level down the hierarchy. "member" follows the standard GML property pattern whereby its (complex) value may be either described fully inline, or may be the target of a link carried on the member element and described fully elsewhere, either in the same document or from another service.</documentation></annotation></element>
In a particular Time System, an Era may be a member of a group. The "group" element implements the back-pointer to the Era
at the next level up in the hierarchy.
If the hierarchy is represented by describing the nested components fully in the their nested position inside "member" elements,
then the parent can be easily inferred, so the group property is unnecessary.
However, if the hierarchy is represented by links carried on the "member" property elements, pointing to Eras described fully
elsewhere, then it may be useful for a child (member) era to carry an explicit pointer back to its parent (group) Era.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
<element name="group" type="gml:ReferenceType" minOccurs="0"><annotation><documentation>In a particular Time System, an Era may be a member of a group. The "group" element implements the back-pointer to the Era at the next level up in the hierarchy.
If the hierarchy is represented by describing the nested components fully in the their nested position inside "member" elements, then the parent can be easily inferred, so the group property is unnecessary.
However, if the hierarchy is represented by links carried on the "member" property elements, pointing to Eras described fully elsewhere, then it may be useful for a child (member) era to carry an explicit pointer back to its parent (group) Era.</documentation></annotation></element>
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
<element name="referenceFrame" type="gml:TimeCalendarEraPropertyType" maxOccurs="unbounded"><annotation><documentation>Link to the CalendarEras that it uses as a reference for dating.</documentation></annotation></element>
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
<element name="referenceEvent" type="gml:StringOrRefType"><annotation><documentation>Name or description of a mythical or historic event which fixes the position of the base scale of the calendar era.</documentation></annotation></element>
Date of the referenceEvent expressed as a date in the given calendar.
In most calendars, this date is the origin (i.e., the first day) of the scale, but this is not always true.
Diagram
Type
date
Properties
content:
simple
minOccurs:
0
default:
0001-01-01
Source
<element name="referenceDate" type="date" default="0001-01-01" minOccurs="0"><annotation><documentation>Date of the referenceEvent expressed as a date in the given calendar.
In most calendars, this date is the origin (i.e., the first day) of the scale, but this is not always true.</documentation></annotation></element>
Julian date that corresponds to the reference date.
The Julian day numbering system is a temporal coordinate system that has an
origin earlier than any known calendar,
at noon on 1 January 4713 BC in the Julian proleptic calendar.
The Julian day number is an integer value;
the Julian date is a decimal value that allows greater resolution.
Transforming calendar dates to and from Julian dates provides a
relatively simple basis for transforming dates from one calendar to another.
Diagram
Type
decimal
Properties
content:
simple
Source
<element name="julianReference" type="decimal"><annotation><documentation>Julian date that corresponds to the reference date.
The Julian day numbering system is a temporal coordinate system that has an
origin earlier than any known calendar,
at noon on 1 January 4713 BC in the Julian proleptic calendar.
The Julian day number is an integer value;
the Julian date is a decimal value that allows greater resolution.
Transforming calendar dates to and from Julian dates provides a
relatively simple basis for transforming dates from one calendar to another.</documentation></annotation></element>
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
<element name="epochOfUse" type="gml:TimePeriodPropertyType"><annotation><documentation>Period for which the calendar era was used as a basis for dating.</documentation></annotation></element>
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
<element name="referenceEvent" type="gml:StringOrRefType"><annotation><documentation>Name or description of an event, such as solar noon or sunrise,
which fixes the position of the base scale of the clock.</documentation></annotation></element>
time of day associated with the reference event expressed as
a time of day in the given clock. The reference time is usually the origin of the clock scale.
Diagram
Type
time
Properties
content:
simple
Source
<element name="referenceTime" type="time"><annotation><documentation>time of day associated with the reference event expressed as
a time of day in the given clock. The reference time is usually the origin of the clock scale.</documentation></annotation></element>
24 hour local or UTC time that corresponds to the reference time.
Diagram
Type
time
Properties
content:
simple
Source
<element name="utcReference" type="time"><annotation><documentation>24 hour local or UTC time that corresponds to the reference time.</documentation></annotation></element>
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
A value in the time domain is measured relative to a temporal reference system. Common
types of reference systems include calendars, ordinal temporal reference systems, and
temporal coordinate systems (time elapsed since some epoch, e.g. UNIX time).
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="AbstractTimeReferenceSystemType" abstract="true"><annotation><documentation xml:lang="en">A value in the time domain is measured relative to a temporal reference system. Common
types of reference systems include calendars, ordinal temporal reference systems, and
temporal coordinate systems (time elapsed since some epoch, e.g. UNIX time).</documentation></annotation><complexContent><extension base="gml:DefinitionType"><sequence><element name="domainOfValidity" type="string" minOccurs="0"/></sequence></extension></complexContent></complexType>
Complex Type gml:TimeCoordinateSystemType
Namespace
http://www.opengis.net/gml
Annotations
A temporal coordinate system is based on a continuous interval scale defined in terms of a single time interval.
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="TimeCoordinateSystemType"><annotation><documentation xml:lang="en">A temporal coordinate system is based on a continuous interval scale defined in terms of a single time interval.</documentation></annotation><complexContent><extension base="gml:AbstractTimeReferenceSystemType"><sequence><choice><element name="originPosition" type="gml:TimePositionType"/><element name="origin" type="gml:TimeInstantPropertyType"/></choice><element name="interval" type="gml:TimeIntervalLengthType"/></sequence></extension></complexContent></complexType>
Complex Type gml:TimeOrdinalReferenceSystemType
Namespace
http://www.opengis.net/gml
Annotations
In an ordinal reference system the order of events in time can be well
established, but the magnitude of the intervals between them can not be
accurately determined (e.g. a stratigraphic sequence).
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="TimeOrdinalReferenceSystemType"><annotation><documentation xml:lang="en">In an ordinal reference system the order of events in time can be well
established, but the magnitude of the intervals between them can not be
accurately determined (e.g. a stratigraphic sequence).</documentation></annotation><complexContent><extension base="gml:AbstractTimeReferenceSystemType"><sequence><element name="component" type="gml:TimeOrdinalEraPropertyType" maxOccurs="unbounded"/></sequence></extension></complexContent></complexType>
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
Ordinal temporal reference systems are often hierarchically structured
such that an ordinal era at a given level of the hierarchy includes a
sequence of shorter, coterminous ordinal eras. This captured using the member/group properties.
Note that in this schema, TIme Ordinal Era is patterned on TimeEdge, which is a variation from ISO 19108.
This is in order to fulfill the requirements of ordinal reference systems based on eras delimited by
named points or nodes, which are common in geology, archeology, etc.
This change is subject of a change proposal to ISO
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="TimeOrdinalEraType"><annotation><documentation xml:lang="en">Ordinal temporal reference systems are often hierarchically structured
such that an ordinal era at a given level of the hierarchy includes a
sequence of shorter, coterminous ordinal eras. This captured using the member/group properties.
Note that in this schema, TIme Ordinal Era is patterned on TimeEdge, which is a variation from ISO 19108.
This is in order to fulfill the requirements of ordinal reference systems based on eras delimited by
named points or nodes, which are common in geology, archeology, etc.
This change is subject of a change proposal to ISO</documentation></annotation><complexContent><extension base="gml:DefinitionType"><sequence><element name="relatedTime" type="gml:RelatedTimeType" minOccurs="0" maxOccurs="unbounded"/><element name="start" type="gml:TimeNodePropertyType"/><element name="end" type="gml:TimeNodePropertyType"/><element name="extent" type="gml:TimePeriodPropertyType" minOccurs="0"/><element name="member" type="gml:TimeOrdinalEraPropertyType" minOccurs="0" maxOccurs="unbounded"><annotation><documentation>An Era may be composed of several member Eras. The "member" element implements the association to the Era at the next level down the hierarchy. "member" follows the standard GML property pattern whereby its (complex) value may be either described fully inline, or may be the target of a link carried on the member element and described fully elsewhere, either in the same document or from another service.</documentation></annotation></element><element name="group" type="gml:ReferenceType" minOccurs="0"><annotation><documentation>In a particular Time System, an Era may be a member of a group. The "group" element implements the back-pointer to the Era at the next level up in the hierarchy.
If the hierarchy is represented by describing the nested components fully in the their nested position inside "member" elements, then the parent can be easily inferred, so the group property is unnecessary.
However, if the hierarchy is represented by links carried on the "member" property elements, pointing to Eras described fully elsewhere, then it may be useful for a child (member) era to carry an explicit pointer back to its parent (group) Era.</documentation></annotation></element></sequence></extension></complexContent></complexType>
Complex Type gml:TimeCalendarType
Namespace
http://www.opengis.net/gml
Annotations
A calendar is a discrete temporal reference system
that provides a basis for defining temporal position to a resolution of one day.
A single calendar may reference more than one calendar era.
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="TimeCalendarType"><annotation><documentation xml:lang="en">A calendar is a discrete temporal reference system
that provides a basis for defining temporal position to a resolution of one day.
A single calendar may reference more than one calendar era.</documentation></annotation><complexContent><extension base="gml:AbstractTimeReferenceSystemType"><sequence><element name="referenceFrame" type="gml:TimeCalendarEraPropertyType" maxOccurs="unbounded"><annotation><documentation>Link to the CalendarEras that it uses as a reference for dating.</documentation></annotation></element></sequence></extension></complexContent></complexType>
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
In every calendar, years are numbered relative to the date of a
reference event that defines a calendar era.
In this implementation, we omit the back-pointer "datingSystem".
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="TimeCalendarEraType"><annotation><documentation xml:lang="en">In every calendar, years are numbered relative to the date of a
reference event that defines a calendar era.
In this implementation, we omit the back-pointer "datingSystem".</documentation></annotation><complexContent><extension base="gml:DefinitionType"><sequence><element name="referenceEvent" type="gml:StringOrRefType"><annotation><documentation>Name or description of a mythical or historic event which fixes the position of the base scale of the calendar era.</documentation></annotation></element><element name="referenceDate" type="date" default="0001-01-01" minOccurs="0"><annotation><documentation>Date of the referenceEvent expressed as a date in the given calendar.
In most calendars, this date is the origin (i.e., the first day) of the scale, but this is not always true.</documentation></annotation></element><element name="julianReference" type="decimal"><annotation><documentation>Julian date that corresponds to the reference date.
The Julian day numbering system is a temporal coordinate system that has an
origin earlier than any known calendar,
at noon on 1 January 4713 BC in the Julian proleptic calendar.
The Julian day number is an integer value;
the Julian date is a decimal value that allows greater resolution.
Transforming calendar dates to and from Julian dates provides a
relatively simple basis for transforming dates from one calendar to another.</documentation></annotation></element><element name="epochOfUse" type="gml:TimePeriodPropertyType"><annotation><documentation>Period for which the calendar era was used as a basis for dating.</documentation></annotation></element></sequence></extension></complexContent></complexType>
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
A clock provides a basis for defining temporal position within a day.
A clock must be used with a calendar in order to provide a complete description of a temporal position
within a specific day.
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it
occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods.
This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="TimeClockType" final="#all"><annotation><documentation xml:lang="en">A clock provides a basis for defining temporal position within a day.
A clock must be used with a calendar in order to provide a complete description of a temporal position
within a specific day.</documentation></annotation><complexContent><extension base="gml:AbstractTimeReferenceSystemType"><sequence><element name="referenceEvent" type="gml:StringOrRefType"><annotation><documentation>Name or description of an event, such as solar noon or sunrise,
which fixes the position of the base scale of the clock.</documentation></annotation></element><element name="referenceTime" type="time"><annotation><documentation>time of day associated with the reference event expressed as
a time of day in the given clock. The reference time is usually the origin of the clock scale.</documentation></annotation></element><element name="utcReference" type="time"><annotation><documentation>24 hour local or UTC time that corresponds to the reference time.</documentation></annotation></element><element name="dateBasis" type="gml:TimeCalendarPropertyType" minOccurs="0" maxOccurs="unbounded"/></sequence></extension></complexContent></complexType>
Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the
XML Schema Section 4.14 Referencing Schemas from Elsewhere.
