# Class Latitude

Object
Angle
Latitude

All Implemented Interfaces:
  `Serializable, Comparable<Angle>, Formattable`

public final class Latitude extends Angle
A latitude angle in decimal degrees. Positive latitudes are North, while negative latitudes are South. The latitude symbol is the Greek lower-case letter phi (φ).

Because the Earth is not a perfect sphere, there is small differences in the latitude values of a point depending on how the latitude is defined:

- Geodetic latitude is the angle between the equatorial plane and a line perpendicular to the ellipsoid surface.
- Geocentric latitude is the angle between the equatorial plane and a line going from the Earth center. It differs from geodetic latitude by less than 11 angular minutes.
- Astronomical latitude is the angle between the equatorial plane and a line given by the direction of a plumb line (the "true vertical").
- Above list is not exhaustive. There is also geomagnetic latitude, etc.

The kind of latitude is unspecified by this `Latitude` class, and rather depends on the context: the latitude is geodetic if the coordinate reference system is geographic, or geocentric if the coordinate reference system is geocentric. If the context is unknown, then geodetic latitude can usually be assumed.

## Immutability and thread safety

This final class is immutable and thus inherently thread-safe.

Since:
  0.3
See Also:
  - `Longitude`
  - `AngleFormat`
  - `CoordinateFormat`
  - Serialized Form

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final double`
  `MAX_VALUE`
  Maximum usual value for latitude (+90.0°).
  `static final double`
  `MIN_VALUE`
  Minimum usual value for latitude (-90.0°).

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Latitude(double φ)`
  Construct a new latitude with the specified angular value.
  `Latitude(String string)`
  Constructs a newly allocated `Latitude` object that contain the angular value represented by the string.
  `Latitude(DirectPosition position)`
  Constructs a newly allocated object containing the latitude value of the given position.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static double`
  `clamp(double φ)`
  Returns the given latitude value clamped to the [-90 … 90]° range.

  ### Methods inherited from class Angle

  `compareTo, degrees, equals, formatTo, hashCode, radians, toString`

  ### Methods inherited from class Object

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

- ## Field Details

  - ### MIN_VALUE

    public static final double MIN_VALUE
    Minimum usual value for latitude (-90.0°).
    See Also:
      - `DefaultCoordinateSystemAxis​.getMinimumValue()`
      - Constant Field Values

  - ### MAX_VALUE

    public static final double MAX_VALUE
    Maximum usual value for latitude (+90.0°).
    See Also:
      - `DefaultCoordinateSystemAxis​.getMaximumValue()`
      - Constant Field Values

- ## Constructor Details

  - ### Latitude

    public Latitude(double φ)
    Construct a new latitude with the specified angular value.
    Parameters:
      `φ` - latitude value in decimal degrees.

  - ### Latitude

    public Latitude(String string) throws NumberFormatException
    Constructs a newly allocated `Latitude` object that contain the angular value represented by the string. The string should represent an angle in either fractional degrees (e.g. 45.5°) or degrees with minutes and seconds (e.g. 45°30'). The hemisphere (N or S) is optional (default to North).

    This is a convenience constructor mostly for testing purpose, since it uses a fixed locale. Developers should consider using `AngleFormat` for end-user applications instead of this constructor.

    Parameters:
      `string` - a string to be converted to a `Latitude`.
    Throws:
      `NumberFormatException` - if the string does not contain a parsable angle, or represents a longitude angle.
    See Also:
      - `AngleFormat​.parse(String)`

  - ### Latitude

    public Latitude(DirectPosition position) throws IllegalArgumentException
    Constructs a newly allocated object containing the latitude value of the given position. For this method, the latitude value is defined as the angular value associated to the first axis oriented toward North or South. Note that this is not necessarily the geodetic latitudes used in geographic CRS; it may also be geocentric latitudes.

    If the axis direction is South, then the sign of the coordinate value is inverted. If the coordinate value uses another angular units than degrees, then a unit conversion is applied.

    Parameters:
      `position` - the coordinate from which to extract the latitude value in degrees.
    Throws:
      `IllegalArgumentException` - if the given coordinate it not associated to a CRS, or if no axis oriented toward North or South is found, or if that axis does not use angular units.
    Since:
      0.8

- ## Method Details

  - ### clamp

    public static double clamp(double φ)
    Returns the given latitude value clamped to the [-90 … 90]° range. If the given value is outside the latitude range, then this method replaces it by ±90° with the same sign as the given φ value.

    Special cases:

    - NaN values are returned unchanged
    - ±∞ are mapped to ±90° (with the same sign)
    - ±0 are returned unchanged (i.e. the sign of negative and positive zero is preserved)
    Parameters:
      `φ` - the latitude value in decimal degrees.
    Returns:
      the given value clamped to the [-90 … 90]° range, or NaN if the given value was NaN.
    Since:
      0.4
    See Also:
      - `Longitude​.normalize(double)`