Package com.luciad.format.asterix

Class ALcdASTERIXTransformationProvider

java.lang.Object

com.luciad.format.asterix.ALcdASTERIXTransformationProvider

public abstract class ALcdASTERIXTransformationProvider
extends Object

Provides the transformations needed to convert ASTERIX coordinates to WGS_84 lon/lat coordinates. Some ASTERIX categories use a local coordinate system, locations are for example specified relative to the radar location, but that radar location is not present in the data. Furthermore the details of how these coordinates need to be interpreted (the exact definition of the grid reference) is radar dependent. This provider allows to implement a transformation specific per radar system and per data category.

Note that this class is not used for ASTERIX category 240 (radar video). To correctly georeference category 240 data, see ALcdASTERIXReferenceProvider.

Constructor Summary

Constructors

Constructor	Description
ALcdASTERIXTransformationProvider()

Method Summary

Modifier and Type	Method	Description
abstract ILcdModelModelTransformation	provideModelModelTransformation(int aSacSic, ILcdModel aModel, Object aObject)	Returns the transformation used to convert ASTERIX coordinates to WGS_84 lon/lat coordinates.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ALcdASTERIXTransformationProvider

public ALcdASTERIXTransformationProvider()

Method Details

provideModelModelTransformation

public abstract ILcdModelModelTransformation provideModelModelTransformation(int aSacSic,
 ILcdModel aModel,
 Object aObject)

Returns the transformation used to convert ASTERIX coordinates to WGS_84 lon/lat coordinates. The source and destination references must be set to the ILcdModelModelTransformation return by the implementation of this method.

The source reference of the returned ILcdModelModelTransformation should be the reference representing the ASTERIX coordinate system. This can be different per category:

Category	Coordinate system
1	Grid coordinates relative to the radar
30	Grid coordinates relative to the radar
48	Grid coordinates relative to the radar
62	Grid coordinates relative to the radar

Please refer to the asterix specifications for details about the used coordinate systems (www.eurocontrol.int/asterix).

Note that in a future version new categories might be added that use a different coordinate system.

The destination reference of the provided ILcdModelModelTransformation should be WGS 84, e.g. new TLcdGeodeticReference( new TLcdGeodeticDatum() ).

This method should perform very fast, as it is invoked frequently.

Parameters:

aSacSic - The System Area Code (SAC) and System Identification Code (SIC) defining which surveillance system (radar) is used. Bits 9 to 16 represent the SAC code, the geographical area. The lower 8 bits represent the SIC code, the identification of a surveillance system within the given SAC. An overview of available SAC codes can be retrieved from www.eurocontrol.int/asterix.

aModel - The model. Can for example be used to retrieve the user application profile, using aModel.getModelDescriptor and casting to ALcdASTERIXModelDescriptor.

aObject - The domain object, e.g. a trajectory, a track, ... Can be used to retrieve specific information needed to provide the transformation.

Returns:

The transformation for the given parameters. The value must not be null: a default value must be returned for unknown parameters.