Package org.apache.sis.referencing.datum

Class DefaultPrimeMeridian

java.lang.Object
org.apache.sis.io.wkt.FormattableObject
org.apache.sis.referencing.AbstractIdentifiedObject
org.apache.sis.referencing.datum.DefaultPrimeMeridian
All Implemented Interfaces:
Serializable, Formattable, Deprecable, LenientComparable, org.opengis.referencing.datum.PrimeMeridian, org.opengis.referencing.IdentifiedObject
public class DefaultPrimeMeridian extends AbstractIdentifiedObject implements org.opengis.referencing.datum.PrimeMeridian
Defines the origin from which longitude values are determined.

Creating new prime meridian instances

New instances can be created either directly by specifying all information to a factory method (choices 3 and 4 below), or indirectly by specifying the identifier of an entry in a database (choices 1 and 2 below). In particular, the EPSG repository provides definitions for many prime meridians, and Apache SIS provides convenience shortcuts for some of them.

Choice 1 in the following list is the easiest but most restrictive way to get a prime meridian. The other choices provide more freedom. Each choice delegates its work to the subsequent items (in the default configuration), so this list can be seen as top to bottom API.

  1. Create a PrimeMeridian from one of the static convenience shortcuts listed in CommonCRS.primeMeridian().
  2. Create a PrimeMeridian from an identifier in a database by invoking DatumAuthorityFactory.createPrimeMeridian(String).
  3. Create a PrimeMeridian by invoking the DatumFactory.createPrimeMeridian(…) method (implemented for example by GeodeticObjectFactory).
  4. Create a DefaultPrimeMeridian by invoking the constructor.
Example: the following code gets the Greenwich prime meridian:

Immutability and thread safety

This class is immutable and thus thread-safe if the property values (not necessarily the map itself) given to the constructor are also immutable. Unless otherwise noted in the javadoc, this condition holds if all components were created using only SIS factories and static constants.
Since:
0.4
Version:
0.7
Author:
Martin Desruisseaux (IRD, Geomatys), Cédric Briançon (Geomatys)
See Also:

  • Constructor Details

    • DefaultPrimeMeridian

      public DefaultPrimeMeridian(Map<String,?> properties, double greenwichLongitude, javax.measure.Unit<javax.measure.quantity.Angle> angularUnit)
      Creates a prime meridian from the given properties. 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.
      greenwichLongitude - the longitude value relative to the Greenwich Meridian.
      angularUnit - the angular unit of the longitude.
      See Also:

    • DefaultPrimeMeridian

      protected DefaultPrimeMeridian(org.opengis.referencing.datum.PrimeMeridian meridian)
      Creates a new prime meridian with the same values than 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:
      meridian - the prime meridian to copy.
      See Also:

  • Method Details

    • castOrCopy

      public static DefaultPrimeMeridian castOrCopy(org.opengis.referencing.datum.PrimeMeridian object)
      Returns a SIS prime meridian implementation with the same values than the given arbitrary implementation. If the given object is null, then this method returns null. Otherwise if the given object is already a SIS implementation, then the given object is returned unchanged. Otherwise a new SIS implementation is created and initialized to the attribute values of the given object.
      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 org.opengis.referencing.datum.PrimeMeridian> getInterface()
      Returns the GeoAPI interface implemented by this class. The SIS implementation returns PrimeMeridian.class.
      Note for implementers: Subclasses usually do not need to override this method since GeoAPI does not define PrimeMeridian sub-interface. Overriding possibility is left mostly for implementers who wish to extend GeoAPI with their own set of interfaces.
      Overrides:
      getInterface in class AbstractIdentifiedObject
      Returns:
      PrimeMeridian.class or a user-defined sub-interface.

    • getGreenwichLongitude

      public double getGreenwichLongitude()
      Longitude of the prime meridian measured from the Greenwich meridian, positive eastward.
      Specified by:
      getGreenwichLongitude in interface org.opengis.referencing.datum.PrimeMeridian
      Returns:
      the prime meridian Greenwich longitude, in angular unit.

    • getGreenwichLongitude

      public double getGreenwichLongitude(javax.measure.Unit<javax.measure.quantity.Angle> unit)
      Returns the longitude value relative to the Greenwich Meridian, expressed in the specified units. This convenience method makes it easier to obtain longitude in decimal degrees using the following code, regardless of the underlying angular units of this prime meridian:
      Parameters:
      unit - the unit in which to express longitude.
      Returns:
      the Greenwich longitude in the given units.

    • getAngularUnit

      public javax.measure.Unit<javax.measure.quantity.Angle> getAngularUnit()
      Returns the angular unit of the Greenwich longitude.
      Specified by:
      getAngularUnit in interface org.opengis.referencing.datum.PrimeMeridian
      Returns:
      the angular unit of the Greenwich longitude.

    • equals

      public boolean equals(Object object, ComparisonMode mode)
      Compares this prime meridian with the specified object for equality.
      Specified by:
      equals in interface LenientComparable
      Overrides:
      equals in class AbstractIdentifiedObject
      Parameters:
      object - the object to compare to this.
      mode - STRICT for performing a strict comparison, or IGNORE_METADATA for comparing only properties relevant to coordinate transformations.
      Returns:
      true if both objects are equal.
      See Also:

    • computeHashCode

      protected long computeHashCode()
      Invoked by hashCode() for computing the hash code when first needed. See AbstractIdentifiedObject.computeHashCode() for more information.
      Overrides:
      computeHashCode in class AbstractIdentifiedObject
      Returns:
      the hash code value. This value may change in any future Apache SIS version.

    • formatTo

      protected String formatTo(Formatter formatter)
      Formats this prime meridian as a Well Known Text PrimeMeridian[…] element.
      Overrides:
      formatTo in class AbstractIdentifiedObject
      Parameters:
      formatter - the formatter where to format the inner content of this WKT element.
      Returns:
      "PrimeMeridian" (WKT 2) or "PrimeM" (WKT 1).
      See Also: