# Class AbstractCS

Object
FormattableObject
AbstractIdentifiedObject
AbstractCS

All Implemented Interfaces:
  `Serializable, Formattable, Deprecable, LenientComparable, Printable, CoordinateSystem, IdentifiedObject`

Direct Known Subclasses:
  `DefaultAffineCS, DefaultCompoundCS, DefaultCylindricalCS, DefaultEllipsoidalCS, DefaultLinearCS, DefaultParametricCS, DefaultPolarCS, DefaultSphericalCS, DefaultTimeCS, DefaultVerticalCS`

public class AbstractCS extends AbstractIdentifiedObject implements CoordinateSystem
The set of coordinate system axes that spans a given coordinate space. The type of the coordinate system implies the set of mathematical rules for calculating geometric properties like angles, distances and surfaces.

This class is conceptually abstract, even if it is technically possible to instantiate it. Typical applications should create instances of the most specific subclass with `Default` prefix instead. An exception to this rule may occurs when it is not possible to identify the exact type. For example, it is not possible to infer the exact coordinate system from Well Known Text (WKT) version 1 in some cases (e.g. in a `LOCAL_CS` element). In such exceptional situation, a plain `AbstractCS` object may be instantiated.

## Immutability and thread safety

This base class is immutable and thus thread-safe if the property values (not necessarily the map itself) and the `CoordinateSystemAxis` instances given to the constructor are also immutable. Most SIS subclasses and related classes are immutable under similar conditions. This means that unless otherwise noted in the javadoc, `CoordinateSystem` instances created using only SIS factories and static constants can be shared by many objects and passed between threads without synchronization.

Since:
  0.4
See Also:
  - `DefaultCoordinateSystemAxis`
  - `AbstractCRS`
  - Serialized Form

- ## Field Summary

  ### Fields inherited from class AbstractIdentifiedObject

  `DEPRECATED_KEY, DOMAINS_KEY, LOCALE_KEY`

  ### Fields inherited from interface IdentifiedObject

  `ALIAS_KEY, IDENTIFIERS_KEY, NAME_KEY, REMARKS_KEY`

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  ``
  `AbstractCS(Map<String,?> properties, CoordinateSystemAxis... axes)`
  Constructs a coordinate system from a set of properties and a sequence of axes.
  `protected`
  `AbstractCS(CoordinateSystem original)`
  Creates a new coordinate system with the same values as the specified one.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static AbstractCS`
  `castOrCopy(CoordinateSystem object)`
  Returns a SIS coordinate system implementation with the values of the given arbitrary implementation.
  `AbstractCS`
  `forConvention(AxesConvention convention)`
  Returns a coordinate system equivalent to this one but with axes rearranged according the given convention.
  `protected String`
  `formatTo(Formatter formatter)`
  Formats the inner part of the Well Known Text (WKT) representation of this coordinate system.
  `final CoordinateSystemAxis`
  `getAxis(int dimension)`
  Returns the axis for this coordinate system at the specified dimension.
  `final int`
  `getDimension()`
  Returns the number of dimensions of this coordinate system.
  `Class<? extends CoordinateSystem>`
  `getInterface()`
  Returns the GeoAPI interface implemented by this class.
  `final boolean`
  `hasSameAxes(CoordinateSystem other)`
  Returns whether this coordinate system has the same axes as the specified CS, ignoring axis order.

  ### Methods inherited from class AbstractIdentifiedObject

  `castOrCopy, equals, formatTo, getAlias, getDescription, getDomains, getIdentifiers, getName, getRemarks, hashCode, isDeprecated, isHeuristicMatchForName`

  ### Methods inherited from class FormattableObject

  `print, toString, toString, toWKT`

  ### Methods inherited from class Object

  `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

  ### Methods inherited from interface IdentifiedObject

  `getAlias, getIdentifiers, getName, getRemarks, toWKT`

- ## Constructor Details

  - ### AbstractCS

    public AbstractCS(Map<String,?> properties, CoordinateSystemAxis... axes)
    Constructs a coordinate system from a set of properties and a sequence of axes. The properties map is given unchanged to the super-class constructor. The following table is a reminder of main (not all) properties:

    Recognized properties (non exhaustive list)
    Property name | Value type | Returned by
    --- | --- | ---
    "name" | `ReferenceIdentifier` or `String` | `AbstractIdentifiedObject.getName()`
    "alias" | `GenericName` or `CharSequence` (optionally as array) | `AbstractIdentifiedObject.getAlias()`
    "identifiers" | `ReferenceIdentifier` (optionally as array) | `AbstractIdentifiedObject.getIdentifiers()`
    "remarks" | `InternationalString` or `String` | `AbstractIdentifiedObject.getRemarks()`

    Parameters:
      `properties` - the properties to be given to the identified object.
      `axes` - the sequence of axes.
    Throws:
      `IllegalArgumentException` - if an axis has an illegal direction or an illegal unit of measurement.

  - ### AbstractCS

    protected AbstractCS(CoordinateSystem original)
    Creates a new coordinate system with the same values as the specified one. This copy constructor provides a way to convert an arbitrary implementation into a SIS one or a user-defined one (as a subclass), usually in order to leverage some implementation-specific API.

    This constructor performs a shallow copy, i.e. the properties are not cloned.

    Parameters:
      `original` - the coordinate system to copy.
    See Also:
      - `castOrCopy(CoordinateSystem)`

- ## Method Details

  - ### castOrCopy

    public static AbstractCS castOrCopy(CoordinateSystem object)
    Returns a SIS coordinate system implementation with the values of the given arbitrary implementation. This method performs the first applicable action in the following choices:
    - If the given object is `null`, then this method returns `null`.
    - Otherwise if the given object is an instance of `AffineCS`, `CartesianCS`, `SphericalCS`, `EllipsoidalCS`, `CylindricalCS`, `PolarCS`, `LinearCS`, `VerticalCS`, `TimeCS` or `UserDefinedCS`, then this method delegates to the `castOrCopy(…)` method of the corresponding SIS subclass. Note that if the given object implements more than one of the above-cited interfaces, then the `castOrCopy(…)` method to be used is unspecified.
    - Otherwise if the given object is already an instance of `AbstractCS`, then it is returned unchanged.
    - Otherwise a new `AbstractCS` instance is created using the copy constructor and returned. Note that this is a shallow copy operation, because the other properties contained in the given object are not recursively copied.
    Parameters:
      `object` - the object to get as a SIS implementation, or `null` if none.
    Returns:
      a SIS implementation containing the values of the given object (may be the given object itself), or `null` if the argument was null.

  - ### getInterface

    public Class<? extends CoordinateSystem> getInterface()
    Returns the GeoAPI interface implemented by this class. The default implementation returns `CoordinateSystem​.class`. Subclasses implementing a more specific GeoAPI interface shall override this method.
    Overrides:
      `getInterface` in class `AbstractIdentifiedObject`
    Returns:
      the coordinate system interface implemented by this class.

  - ### getDimension

    public final int getDimension()
    Returns the number of dimensions of this coordinate system. This is the number of axes given at construction time.
    Specified by:
      `getDimension` in interface `CoordinateSystem`
    Returns:
      the number of dimensions of this coordinate system.

  - ### getAxis

    public final CoordinateSystemAxis getAxis(int dimension) throws IndexOutOfBoundsException
    Returns the axis for this coordinate system at the specified dimension.
    Specified by:
      `getAxis` in interface `CoordinateSystem`
    Parameters:
      `dimension` - the zero based index of axis.
    Returns:
      the axis at the specified dimension.
    Throws:
      `IndexOutOfBoundsException` - if `dimension` is out of bounds.

  - ### hasSameAxes

    public final boolean hasSameAxes(CoordinateSystem other)
    Returns whether this coordinate system has the same axes as the specified CS, ignoring axis order. If true, then the two coordinate systems have the same number of dimensions and the same set of axes. Axis instances are compared by the identity operator (`==`), not by `equals(Object)`.

    #### Purpose

    This method can be invoked after a call to `forConvention(AxesConvention)` for checking if that method changed only the axis order, with no change to axis directions, axis ranges or units of measurement.
    Parameters:
      `other` - the other coordinate system to compare with this CS.
    Returns:
      whether this coordinate system has the same axes as the specified CS.
    Since:
      1.5

  - ### forConvention

    public AbstractCS forConvention(AxesConvention convention)
    Returns a coordinate system equivalent to this one but with axes rearranged according the given convention. If this coordinate system is already compatible with the given convention, then this method returns `this`.
    Parameters:
      `convention` - the axes convention for which a coordinate system is desired.
    Returns:
      a coordinate system compatible with the given convention (may be `this`).
    See Also:
      - `AbstractCRS​.forConvention(AxesConvention)`

  - ### formatTo

    protected String formatTo(Formatter formatter)
    Formats the inner part of the Well Known Text (WKT) representation of this coordinate system. This method does not format the axes, because they shall appear outside the `CS[…]` element for historical reasons. Axes shall be formatted by the enclosing element (usually an `AbstractCRS`).

    #### Example

    Well-Known Text of a two-dimensional `EllipsoidalCS` having (φ,λ) axes in a unit defined by the enclosing CRS (usually degrees).

          CS[ellipsoidal, 2],
          Axis["latitude", north],
          Axis["longitude", east]

    #### Compatibility note

    `CS` is defined in the WKT 2 specification only.
    Overrides:
      `formatTo` in class `AbstractIdentifiedObject`
    Parameters:
      `formatter` - the formatter where to format the inner content of this WKT element.
    Returns:
      `"CS"`.
    See Also:
      - `FormattableObject​.toWKT()`
      - `FormattableObject​.toString()`