Module org.opengis.geoapi

Package org.opengis.referencing.cs

Interface TimeCS

All Superinterfaces:

CoordinateSystem, IdentifiedObject

@UML(identifier="TemporalCS",
     specification=ISO_19111)
public interface TimeCS
extends CoordinateSystem

A 1-dimensional coordinate system containing a single time axis. This coordinate system is used to describe the temporal position of a point in the specified time units from a time origin implied by the temporal datum. ISO 19111 defines three forms of temporal coordinate system:

• Measure of a temporal quantity as real numbers.
• Count of a temporal quantity as integer numbers.
• Numbers related to dates or times expressed in the proleptic Gregorian calendar.

Those forms are specified by getCoordinateType(). GeoAPI does not define specialized sub-interfaces for each form.

This type of CS can be used by coordinate reference systems of type TemporalCRS, potentially in combination with DerivedCRS.

Since:

2.0

See Also:

• CSAuthorityFactory.createTimeCS(String)
• CSFactory.createTimeCS(Map, CoordinateSystemAxis)

Departure from OGC/ISO standard for closer integration with the Java environment

ISO 19111:2019 renamed this interface from TimeCS to TemporalCS. GeoAPI has kept the ISO 19111:2007 interface name for historical reasons, but also to emphasize the relationship with the java.time package.

Field Summary

Fields inherited from interface org.opengis.referencing.IdentifiedObject

ALIAS_KEY, DOMAINS_KEY, IDENTIFIERS_KEY, NAME_KEY, REMARKS_KEY

Method Summary

Modifier and Type	Method	Description
CoordinateDataType	getCoordinateType()	Returns the type (measure, integer or data-time) of coordinate values.
default int	getDimension()	Returns the number of dimensions, which is 1 for this type of coordinate system.
default TemporalUnit	getTemporalUnit()	Returns the unit of measurement of coordinate values.

Methods inherited from interface org.opengis.referencing.cs.CoordinateSystem

getAxis

Methods inherited from interface org.opengis.referencing.IdentifiedObject

getAlias, getDomains, getIdentifiers, getName, getRemarks, toWKT

Method Details

getDimension

default int getDimension()

Returns the number of dimensions, which is 1 for this type of coordinate system.

Specified by:

getDimension in interface CoordinateSystem

Returns:

always 1.

getCoordinateType

@UML(identifier="coordinateType",
     obligation=MANDATORY,
     specification=ISO_19111)
CoordinateDataType getCoordinateType()

Returns the type (measure, integer or data-time) of coordinate values. If the time interval between two integer values is constant and interpolations are allowed, then the returned value will typically be CoordinateDataType.MEASURE. If the time interval is not constant but can be related to some field of the Gregorian calendar (e.g., months or years), then the returned value can be CoordinateDataType.DATE_TIME.

Returns:

the type of coordinate values.

Since:

3.1

getTemporalUnit

default TemporalUnit getTemporalUnit()

Returns the unit of measurement of coordinate values. The returned unit is equivalent to the unit returned by CoordinateSystemAxis.getUnit(), but expressed as a java.time object, preferably an instance from the ChronoUnit enumeration.

Note that contrarily to the usual units of measurement, the duration of java.time units can vary. For example ChronoUnit.DAYS is estimated to be about 24 hours long, because the actual duration can vary due to daylight saving time changes. Implementations can specify whether the temporal unit is estimated or exact with TemporalUnit.isDurationEstimated().

Default implementation

The default implementation returns a ChronoUnit or a multiple of a ChronoUnit with a duration equals to 1 axis unit. If and only if the coordinate type is CoordinateDataType.DATE_TIME, the search for ChronoUnit is relaxed with an arbitrary tolerance of one hour per month for units equal or longer than ChronoUnit.MONTHS. The intend is to accept different definitions of years, for example, 365.2425 days according Java versus 365.24219265 days according the IUGS definition of tropical year.

Returns:

unit measurement of coordinate values, preferably as a ChronoUnit enumeration value.

Since:

3.1

See Also:

• ChronoUnit.SECONDS
• ChronoUnit.DAYS
• ChronoUnit.YEARS