Module org.opengis.geoapi

Package org.opengis.referencing.cs

Interface CoordinateSystemAxis

All Superinterfaces:

IdentifiedObject

@UML(identifier="CoordinateSystemAxis",
     specification=ISO_19111)
public interface CoordinateSystemAxis
extends IdentifiedObject

Definition of a coordinate system axis. Each axis is characterized by a unique combination of name, abbreviation, direction and unit.

Axis name

Usage of coordinate system axis names is constrained by geodetic custom in a number of cases, depending mainly on the coordinate reference system type. These constraints are shown in the table below. This constraint works in two directions; for example the names geodetic latitude and geodetic longitude shall be used to designate the coordinate axis names associated with a geographic coordinate reference system. Conversely, these names shall not be used in any other context.

Context of coordinate system axis names usage

CS	CRS	Permitted coordinate system axis names
Cartesian	Geodetic	“geocentric X”, “geocentric Y”, “geocentric Z”
Cartesian	Projected	“easting” or “westing”, “northing” or “southing”, “ellipsoidal height” (if 3D)
Ellipsoidal	Geographic	“geodetic latitude”, “geodetic longitude”, “ellipsoidal height” (if 3D)
Spherical	Geodetic	“spherical latitude”, “spherical longitude”, “geocentric radius” (if 3D)
″	″	“geocentric latitude”, “geodetic longitude”, “geocentric radius” (if 3D)
″	″	“geocentric co-latitude”, “geodetic longitude”, “geocentric radius” (if 3D)
Vertical	Vertical	“depth” or “gravity-related height”

Parametric, temporal and engineering coordinate reference systems may make use of names specific to the local context or custom and are therefore not included as constraints in the above list.

Axis direction

The direction of the coordinate axes is often only approximate. Two geographic coordinate reference systems will make use of the same ellipsoidal coordinate system. These coordinate systems are associated with the planet through two different geodetic reference frames, which may lead to the two systems being slightly rotated with respect to each other.

Since:

1.0

See Also:

• CoordinateSystem
• CSAuthorityFactory.createCoordinateSystemAxis(String)
• CSFactory.createCoordinateSystemAxis(Map, String, AxisDirection, Unit)

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
String	getAbbreviation()	Returns the abbreviation used for this coordinate system axes.
AxisDirection	getDirection()	Returns the direction of this coordinate system axis.
default double	getMaximumValue()	Returns the maximum value normally allowed for this axis.
default double	getMinimumValue()	Returns the minimum value normally allowed for this axis.
default RangeMeaning	getRangeMeaning()	Returns the meaning of axis value range specified by the minimum and maximum values.
javax.measure.Unit<?>	getUnit()	Returns the unit of measure used for this coordinate system axis.

Methods inherited from interface org.opengis.referencing.IdentifiedObject

getAlias, getDomains, getIdentifiers, getName, getRemarks, toWKT

Method Details

getAbbreviation

@UML(identifier="axisAbbrev",
     obligation=MANDATORY,
     specification=ISO_19111)
String getAbbreviation()

Returns the abbreviation used for this coordinate system axes. This abbreviation is also used to identify the coordinates in coordinate tuple. Examples are “X” and “Y”.

Returns:

the coordinate system axis abbreviation.

getDirection

@UML(identifier="axisDirection",
     obligation=MANDATORY,
     specification=ISO_19111)
AxisDirection getDirection()

Returns the direction of this coordinate system axis. In the case of Cartesian projected coordinates, this is the direction of this coordinate system axis locally. Examples: north or south, east or west, up or down.

Within any set of coordinate system axes, only one of each pair of terms can be used. For planet-fixed coordinate reference systems, this direction is often approximate and intended to provide a human interpretable meaning to the axis. When a geodetic reference frame is used, the precise directions of the axes may therefore vary slightly from this approximate direction.

Note that an EngineeringCRS often requires specific descriptions of the directions of its coordinate system axes.

Returns:

the coordinate system axis direction.

getUnit

@UML(identifier="axisUnitID",
     obligation=CONDITIONAL,
     specification=ISO_19111)
javax.measure.Unit<?> getUnit()

Returns the unit of measure used for this coordinate system axis. The value of a coordinate in a coordinate tuple shall be recorded using this unit of measure, whenever those coordinates use a coordinate reference system that uses a coordinate system that uses this axis.

Obligation

This element may be null if this axis is part of an ordinal CS (a coordinate system in which axes use integer values) and in the case of a TimeCS using date-time. This property is mandatory for all other cases.

Returns:

the coordinate system axis unit.

getMinimumValue

@UML(identifier="minimumValue",
     obligation=OPTIONAL,
     specification=ISO_19111)
default double getMinimumValue()

Returns the minimum value normally allowed for this axis. The value shall be in the unit of measure for the axis. If there is no minimum value, then this method returns negative infinity.

Returns:

the minimum value, or Double.NEGATIVE_INFINITY if none.

getMaximumValue

@UML(identifier="maximumValue",
     obligation=OPTIONAL,
     specification=ISO_19111)
default double getMaximumValue()

Returns the maximum value normally allowed for this axis. The value shall be in the unit of measure for the axis. If there is no maximum value, then this method returns positive infinity.

Returns:

the maximum value, or Double.POSITIVE_INFINITY if none.

getRangeMeaning

@UML(identifier="rangeMeaning",
     obligation=CONDITIONAL,
     specification=ISO_19111)
default RangeMeaning getRangeMeaning()

Returns the meaning of axis value range specified by the minimum and maximum values. This element shall be omitted when both minimum and maximum values are omitted. It may be included when minimum and/or maximum values are included. If this element is omitted when minimum or maximum values are included, the meaning is unspecified.

Returns:

the range meaning, or null in none.

See Also:

• RangeMeaning.EXACT
• RangeMeaning.WRAPAROUND