Object
- PJ

```
public class PJ
extends Object
```
Wraps the PROJ PJ native data structure. Almost every methods defined in this class are native methods delegating the work to the PROJ library. This class is the only place where such native methods are defined.
In the PROJ library, the PJ structure aggregates in a single place information usually splitted in many different ISO 19111 interfaces: org.opengis.referencing.datum.Ellipsoid, org.opengis.referencing.datum.Datum, org.opengis.referencing.datum.PrimeMeridian, org.opengis.referencing.cs.CoordinateSystem, org.opengis.referencing.crs.CoordinateReferenceSystem and their sub-interfaces. The relationship with the GeoAPI methods is indicated in the "See" tags when appropriate.

从以下版本开始:

4.8

版本:

5.1

嵌套类概要

嵌套类
修饰符和类型类说明

static class PJ.Type
The coordinate reference system (CRS) type returned by getType().

字段概要

字段
修饰符和类型字段说明

static int DIMENSION_MAX
The maximal number of dimension accepted by the transform(PJ, int, double[], int, int) method.

构造器概要

构造器
构造器	说明
`PJ(String definition)`	Creates a new `PJ` structure from the given PROJ definition string.
`PJ(PJ crs, PJ.Type type)`	Creates a new `PJ` structure derived from an existing `PJ` object.

方法概要

所有方法静态方法实例方法具体方法
修饰符和类型	方法	说明
`protected void`	`finalize()`	Deallocates the native PJ data structure.
`char[]`	`getAxisDirections()`	Returns an array of character indicating the direction of each axis.
`String`	`getDefinition()`	Returns the PROJ definition string.
`double`	`getEccentricitySquared()`	Returns the square of the ellipsoid eccentricity (ε²).
`double`	`getGreenwichLongitude()`	Longitude of the prime meridian measured from the Greenwich meridian, positive eastward.
`String`	`getLastError()`	Returns a description of the last error that occurred, or `null` if none.
`double`	`getLinearUnitToMetre(boolean vertical)`	Returns the conversion factor from the linear units to metres.
`double`	`getSemiMajorAxis()`	Returns the value stored in the `a_orig` PJ field.
`double`	`getSemiMinorAxis()`	Returns the value computed from PJ fields by `√((a_orig)² × (1 - es_orig))`.
`PJ.Type`	`getType()`	Returns the Coordinate Reference System type.
`static String`	`getVersion()`	Returns the version number of the PROJ library.
`String`	`toString()`	Returns the string representation of the PJ structure.
`void`	`transform(PJ target, int dimension, double[] coordinates, int offset, int numPts)`	Transforms in-place the coordinates in the given array.

从类继承的方法 Object
clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- 字段详细资料
  - DIMENSION_MAX
```
@Native
public static final int DIMENSION_MAX
```
    The maximal number of dimension accepted by the transform(PJ, int, double[], int, int) method. This upper limit is actually somewhat arbitrary. This limit exists mostly as a safety against potential misuse.
    
    另请参阅:
    
    常量字段值
- 构造器详细资料
  - PJ
```
public PJ(String definition)
   throws IllegalArgumentException
```
    Creates a new PJ structure from the given PROJ definition string.
    
    参数:
    
    definition - the PROJ definition string.
    
    抛出:
    
    IllegalArgumentException - if the PJ structure can not be created from the given string.
  - PJ
```
public PJ(PJ crs,
          PJ.Type type)
   throws IllegalArgumentException
```
    Creates a new PJ structure derived from an existing PJ object. This constructor is usually for getting the base geographic CRS from a projected CRS.
    
    参数:
    
    crs - the CRS (usually projected) from which to derive a new CRS.
    
    type - the type of the new CRS. Currently, only PJ.Type.GEOGRAPHIC is supported.
    
    抛出:
    
    IllegalArgumentException - if the PJ structure can not be created.
- 方法详细资料
  - getVersion
```
public static String getVersion()
```
    Returns the version number of the PROJ library.
    
    返回:
    
    the PROJ release string.
  - getDefinition
```
public String getDefinition()
```
    Returns the PROJ definition string. This is the string given to the constructor, expanded with as much information as possible.
    
    返回:
    
    the PROJ definition string.
  - getType
```
public PJ.Type getType()
```
    Returns the Coordinate Reference System type.
    
    返回:
    
    the CRS type.
  - getSemiMajorAxis
```
public double getSemiMajorAxis()
```
    Returns the value stored in the a_orig PJ field.
    
    返回:
    
    the axis length stored in a_orig.
    
    另请参阅:
    
    org.opengis.referencing.datum.Ellipsoid#getSemiMajorAxis()
  - getSemiMinorAxis
```
public double getSemiMinorAxis()
```
    Returns the value computed from PJ fields by √((a_orig)² × (1 - es_orig)).
    
    返回:
    
    the axis length computed by √((a_orig)² × (1 - es_orig)).
    
    另请参阅:
    
    org.opengis.referencing.datum.Ellipsoid#getSemiMinorAxis()
  - getEccentricitySquared
```
public double getEccentricitySquared()
```
    Returns the square of the ellipsoid eccentricity (ε²). The eccentricity is related to axis length by ε=√(1-(b/a)²). The eccentricity of a sphere is zero.
    
    返回:
    
    the eccentricity.
    
    另请参阅:
    
    org.opengis.referencing.datum.Ellipsoid#isSphere(), org.opengis.referencing.datum.Ellipsoid#getInverseFlattening()
  - getAxisDirections
```
public char[] getAxisDirections()
```
    Returns an array of character indicating the direction of each axis. Directions are characters like 'e' for East, 'n' for North and 'u' for Up.
    
    返回:
    
    the axis directions.
    
    另请参阅:
    
    org.opengis.referencing.cs.CoordinateSystemAxis#getDirection()
  - getGreenwichLongitude
```
public double getGreenwichLongitude()
```
    Longitude of the prime meridian measured from the Greenwich meridian, positive eastward.
    
    返回:
    
    the prime meridian longitude, in degrees.
    
    另请参阅:
    
    org.opengis.referencing.datum.PrimeMeridian#getGreenwichLongitude()
  - getLinearUnitToMetre
```
public double getLinearUnitToMetre(boolean vertical)
```
    Returns the conversion factor from the linear units to metres.
    
    参数:
    
    vertical - false for the conversion factor of horizontal axes, or true for the conversion factor of the vertical axis.
    
    返回:
    
    the conversion factor to metres for the given axis.
  - transform
```
public void transform(PJ target,
                      int dimension,
                      double[] coordinates,
                      int offset,
                      int numPts)
               throws PJException
```
    Transforms in-place the coordinates in the given array. The coordinates array shall contain (x,y,z,…) tuples, where the z and any additional dimensions are optional. Note that any dimension after the z value are ignored.
    Input and output units:
    
    Angular units (as in longitude and latitudes) are decimal degrees.
    
    Linear units are usually metres, but this is actually projection-dependent.
    参数:
    
    target - the target CRS.
    
    dimension - the dimension of each coordinate value. Must be in the [2-100] range.
    
    coordinates - the coordinates to transform, as a sequence of (x,y,<z>,…) tuples.
    
    offset - offset of the first coordinate in the given array.
    
    numPts - number of points to transform.
    
    抛出:
    
    NullPointerException - if the target or coordinates argument is null.
    
    IndexOutOfBoundsException - if the offset or numPts arguments are invalid.
    
    PJException - if the operation failed for another reason (provided by PROJ).
    
    另请参阅:
    
    org.opengis.referencing.operation.MathTransform#transform(double[], int, double[], int, int)
  - getLastError
```
public String getLastError()
```
    Returns a description of the last error that occurred, or null if none.
    
    返回:
    
    the last error that occurred, or null.
  - toString
```
public String toString()
```
    Returns the string representation of the PJ structure.
    
    覆盖:
    
    toString 在类中 Object
    
    返回:
    
    the string representation.
  - finalize
```
protected final void finalize()
```
    Deallocates the native PJ data structure. This method should be invoked exactly once, only by the garbage collector,
    
    覆盖:
    
    finalize 在类中 Object

类 PJ

嵌套类概要

字段概要

构造器概要

方法概要

从类继承的方法 Object

字段详细资料

DIMENSION_MAX

构造器详细资料

PJ

PJ

方法详细资料

getVersion

getDefinition

getType

getSemiMajorAxis

getSemiMinorAxis

getEccentricitySquared

getAxisDirections

getGreenwichLongitude

getLinearUnitToMetre

transform

getLastError

toString

finalize