All Known Implementing Classes:

AbstractProj, AlbersEqualArea, AzimuthalEquidistant, CassiniSoldner, DoubleStereographic, EquidistantCylindrical, LambertAzimuthalEqualArea, LambertConformalConic, LonLat, Mercator, ObliqueMercator, PolarStereographic, Sinusoidal, SwissObliqueMercator, TransverseMercator
```
public interface Proj
```
A projection (in the narrow sense). Converts lat/lon the east/north and the other way around. Datum conversion, false easting / northing, origin of longitude and general scale factor is already applied when the projection is invoked. Lat/lon is not in degrees, but in radians (unlike other parts of JOSM). Additional parameters in the constructor arguments are usually still in degrees. So to avoid confusion, you can follow the convention, that coordinates in radians are called lat_rad/lon_rad or phi/lambda. East/north values are not in meters, but in meters divided by the semi major axis of the ellipsoid (earth radius). (Usually this is what you get anyway, unless you multiply by 'a' somehow implicitly or explicitly.)

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`Bounds`	`getAlgorithmBounds()`	Return the bounds where this projection is applicable.
`java.lang.String`	`getName()`	Replies a human readable name of this projection.
`java.lang.String`	`getProj4Id()`	Replies the Proj.4 identifier.
`void`	`initialize(ProjParameters params)`	Initialize the projection using the provided parameters.
`double[]`	`invproject(double east, double north)`	Convert east/north to lat/lon.
`boolean`	`isGeographic()`	Return true, if a geographic coordinate reference system is represented.
`default boolean`	`lonIsLinearToEast()`	Checks whether the result of projecting a lon coordinate only has a linear relation to the east coordinate and is not related to lat/north at all.
`double[]`	`project(double latRad, double lonRad)`	Convert lat/lon to east/north.

- Method Detail
  - getName
```
java.lang.String getName()
```
    Replies a human readable name of this projection.
    
    Returns:
    
    The projection name. must not be null.
  - getProj4Id
```
java.lang.String getProj4Id()
```
    Replies the Proj.4 identifier.
    
    Returns:
    
    The Proj.4 identifier (as reported by cs2cs -lp). If no id exists, return null.
  - initialize
```
void initialize(ProjParameters params)
         throws ProjectionConfigurationException
```
    Initialize the projection using the provided parameters.
    
    Parameters:
    
    params - The projection parameters
    
    Throws:
    
    ProjectionConfigurationException - in case parameters are not suitable
  - project
```
double[] project(double latRad,
                 double lonRad)
```
    Convert lat/lon to east/north.
    
    Parameters:
    
    latRad - the latitude in radians
    
    lonRad - the longitude in radians
    
    Returns:
    
    array of length 2, containing east and north value in meters, divided by the semi major axis of the ellipsoid.
  - invproject
```
double[] invproject(double east,
                    double north)
```
    Convert east/north to lat/lon.
    
    Parameters:
    
    east - east value in meters, divided by the semi major axis of the ellipsoid
    
    north - north value in meters, divided by the semi major axis of the ellipsoid
    
    Returns:
    
    array of length 2, containing lat and lon in radians.
  - getAlgorithmBounds
```
Bounds getAlgorithmBounds()
```
    Return the bounds where this projection is applicable. This is a fallback for when the projection bounds are not specified explicitly. In this area, the round trip lat/lon → east/north → lat/lon should return the starting value with small error. In addition, regions with extreme distortions should be excluded, if possible. It need not be the absolute maximum, but rather an area that is safe to display in JOSM and contain everything that one would expect to use.
    
    Returns:
    
    the bounds where this projection is applicable, null if unknown
  - isGeographic
```
boolean isGeographic()
```
    Return true, if a geographic coordinate reference system is represented. I.e. if it returns latitude/longitude values rather than Cartesian east/north coordinates on a flat surface.
    
    Returns:
    
    true, if it is geographic
  - lonIsLinearToEast
```
default boolean lonIsLinearToEast()
```
    Checks whether the result of projecting a lon coordinate only has a linear relation to the east coordinate and is not related to lat/north at all.
    
    Returns:
    
    true if lon has a linear relationship to east only.
    
    Since:
    
    10805

Interface Proj

Method Summary

Method Detail

getName

getProj4Id

initialize

project

invproject

getAlgorithmBounds

isGeographic

lonIsLinearToEast