Class DefaultPrimeMeridian
- All Implemented Interfaces:
Serializable
,Formattable
,Deprecable
,LenientComparable
,org.opengis.referencing.datum.PrimeMeridian
,org.opengis.referencing.IdentifiedObject
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.
- Create a
PrimeMeridian
from one of the static convenience shortcuts listed inCommonCRS.primeMeridian()
. - Create a
PrimeMeridian
from an identifier in a database by invokingDatumAuthorityFactory.createPrimeMeridian(String)
. - Create a
PrimeMeridian
by invoking theDatumFactory.createPrimeMeridian(…)
method (implemented for example byGeodeticObjectFactory
). - Create a
DefaultPrimeMeridian
by invoking the constructor.
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
- See Also:
-
Field Summary
FieldsModifier and TypeFieldDescriptionprivate javax.measure.Unit<javax.measure.quantity.Angle>
The angular unit of the Greenwich longitude.private double
Longitude of the prime meridian measured from the Greenwich meridian, positive eastward.private static final long
Serial number for inter-operability with different versions.Fields inherited from class org.apache.sis.referencing.AbstractIdentifiedObject
DEPRECATED_KEY, LOCALE_KEY
Fields inherited from interface org.opengis.referencing.IdentifiedObject
ALIAS_KEY, IDENTIFIERS_KEY, NAME_KEY, REMARKS_KEY
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Constructor Summary
ConstructorsModifierConstructorDescriptionprivate
Constructs a new object in which every attributes are set to a null value.DefaultPrimeMeridian
(Map<String, ?> properties, double greenwichLongitude, javax.measure.Unit<javax.measure.quantity.Angle> angularUnit) Creates a prime meridian from the given properties.protected
DefaultPrimeMeridian
(org.opengis.referencing.datum.PrimeMeridian meridian) Creates a new prime meridian with the same values than the specified one. -
Method Summary
Modifier and TypeMethodDescriptionprivate static boolean
beConservative
(Formatter formatter, javax.measure.Unit<javax.measure.quantity.Angle> contextualUnit) Returnstrue
ifformatTo(Formatter)
should conservatively format the angular unit even if it would be legal to omit it.static DefaultPrimeMeridian
castOrCopy
(org.opengis.referencing.datum.PrimeMeridian object) Returns a SIS prime meridian implementation with the same values than the given arbitrary implementation.protected long
Invoked byhashCode()
for computing the hash code when first needed.boolean
equals
(Object object, ComparisonMode mode) Compares this prime meridian with the specified object for equality.protected String
Formats this prime meridian as a Well Known TextPrimeMeridian[…]
element.javax.measure.Unit<javax.measure.quantity.Angle>
Returns the angular unit of the Greenwich longitude.double
Longitude of the prime meridian measured from the Greenwich meridian, positive eastward.double
getGreenwichLongitude
(javax.measure.Unit<javax.measure.quantity.Angle> unit) Returns the longitude value relative to the Greenwich Meridian, expressed in the specified units.private Measure
Invoked by JAXB for obtaining the Greenwich longitude to marshal together with its"uom"
attribute.Class<? extends org.opengis.referencing.datum.PrimeMeridian>
Returns the GeoAPI interface implemented by this class.private static boolean
isElementOfBaseCRS
(Formatter formatter) Returnstrue
if the given formatter is in the process of formatting the prime meridian of a base CRS of anAbstractDerivedCRS
.private void
setGreenwichMeasure
(Measure measure) Invoked by JAXB for setting the Greenwich longitude and its unit of measurement.Methods inherited from class org.apache.sis.referencing.AbstractIdentifiedObject
castOrCopy, equals, formatTo, getAlias, getDescription, getIdentifiers, getName, getRemarks, hashCode, isDeprecated, isHeuristicMatchForName
Methods inherited from class org.apache.sis.io.wkt.FormattableObject
print, toString, toString, toWKT
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.opengis.referencing.IdentifiedObject
getAlias, getIdentifiers, getName, getRemarks, toWKT
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Field Details
-
serialVersionUID
private static final long serialVersionUIDSerial number for inter-operability with different versions.- See Also:
-
greenwichLongitude
private double greenwichLongitudeLongitude of the prime meridian measured from the Greenwich meridian, positive eastward.Consider this field as final! This field is modified only at unmarshalling time by
setGreenwichMeasure(Measure)
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angularUnit
private javax.measure.Unit<javax.measure.quantity.Angle> angularUnitThe angular unit of the Greenwich longitude.Consider this field as final! This field is modified only at unmarshalling time by
setGreenwichMeasure(Measure)
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Constructor Details
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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
orString
AbstractIdentifiedObject.getName()
"alias" GenericName
orCharSequence
(optionally as array)AbstractIdentifiedObject.getAlias()
"identifiers" ReferenceIdentifier
(optionally as array)AbstractIdentifiedObject.getIdentifiers()
"remarks" InternationalString
orString
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:
-
DefaultPrimeMeridian
private DefaultPrimeMeridian()Constructs a new object in which every attributes are set to a null value. This is not a valid object. This constructor is strictly reserved to JAXB, which will assign values to the fields using reflection.
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Method Details
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castOrCopy
Returns a SIS prime meridian implementation with the same values than the given arbitrary implementation. If the given object isnull
, then this method returnsnull
. 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, ornull
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.
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getInterface
Returns the GeoAPI interface implemented by this class. The SIS implementation returnsPrimeMeridian.class
.Note for implementers: Subclasses usually do not need to override this method since GeoAPI does not definePrimeMeridian
sub-interface. Overriding possibility is left mostly for implementers who wish to extend GeoAPI with their own set of interfaces.- Overrides:
getInterface
in classAbstractIdentifiedObject
- 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 interfaceorg.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.
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getAngularUnit
public javax.measure.Unit<javax.measure.quantity.Angle> getAngularUnit()Returns the angular unit of the Greenwich longitude.- Specified by:
getAngularUnit
in interfaceorg.opengis.referencing.datum.PrimeMeridian
- Returns:
- the angular unit of the Greenwich longitude.
-
equals
Compares this prime meridian with the specified object for equality.- Specified by:
equals
in interfaceLenientComparable
- Overrides:
equals
in classAbstractIdentifiedObject
- Parameters:
object
- the object to compare tothis
.mode
-STRICT
for performing a strict comparison, orIGNORE_METADATA
for comparing only properties relevant to coordinate transformations.- Returns:
true
if both objects are equal.- See Also:
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computeHashCode
protected long computeHashCode()Invoked byhashCode()
for computing the hash code when first needed. SeeAbstractIdentifiedObject.computeHashCode()
for more information.- Overrides:
computeHashCode
in classAbstractIdentifiedObject
- Returns:
- the hash code value. This value may change in any future Apache SIS version.
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isElementOfBaseCRS
Returnstrue
if the given formatter is in the process of formatting the prime meridian of a base CRS of anAbstractDerivedCRS
. In such case, base CRS coordinate system axes shall not be formatted, which has the consequence of bringing theUNIT[…]
element right below thePRIMEM[…]
one. Example: If we were not formatting a base CRS, we would have many lines betweenPrimeMeridian[…]
andAngleUnit[…]
in the above example, which would make less obvious that the angle unit applies also to the prime meridian. It does not bring any ambiguity from an ISO 19162 standard point of view, but historically some other software products interpreted thePRIMEM[…]
units wrongly, which is why we try to find a compromise between keeping the WKT simple and avoiding an historical ambiguity.- See Also:
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beConservative
private static boolean beConservative(Formatter formatter, javax.measure.Unit<javax.measure.quantity.Angle> contextualUnit) Returnstrue
ifformatTo(Formatter)
should conservatively format the angular unit even if it would be legal to omit it.Rational
According the ISO 19162 standard, it is legal to omit thePrimeMeridian
angular unit when that unit is the same than the unit of the axes of the enclosingGeographicCRS
. However, the relationship between the CRS axes and the prime meridian is less obvious in WKT2 than it was in WKT1, because the WKT2UNIT[…]
element is far from thePRIMEM[…]
element while it was just below it in WKT1. Furthermore, thePRIMEM[…]
unit is one source of incompatibility between various WKT1 parsers (i.e. some popular libraries are not conform to OGC 01-009 and ISO 19162). So we are safer to unconditionally format any unit other than degrees, even if we could legally omit them.However, in order to keep the WKT slightly simpler in
Convention.WKT2_SIMPLIFIED
mode, we make an exception to the above-cited safety if theUNIT[…]
element is formatted right below thePRIMEM[…]
one, which happen if we are inside a base CRS. SeeisElementOfBaseCRS(Formatter)
for more discussion. -
formatTo
Formats this prime meridian as a Well Known TextPrimeMeridian[…]
element.- Overrides:
formatTo
in classAbstractIdentifiedObject
- Parameters:
formatter
- the formatter where to format the inner content of this WKT element.- Returns:
"PrimeMeridian"
(WKT 2) or"PrimeM"
(WKT 1).- See Also:
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getGreenwichMeasure
Invoked by JAXB for obtaining the Greenwich longitude to marshal together with its"uom"
attribute. -
setGreenwichMeasure
Invoked by JAXB for setting the Greenwich longitude and its unit of measurement.
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