TLcdDTEDModelDecoder (LuciadLightspeed API documentation)

java.lang.Object
- com.luciad.format.raster.TLcdDTEDModelDecoder

All Implemented Interfaces:

ILcdInputStreamFactoryCapable, ILcdModelDecoder
```
@LcdService(service=ILcdModelDecoder.class,
            priority=20000)
public class TLcdDTEDModelDecoder
extends Object
implements ILcdModelDecoder, ILcdInputStreamFactoryCapable
```
This model decoder decodes individual DTED (Digital Terrain Elevation Data) files.
Input files

File Required Entry point Description

*.dt[012] x x DTED file corresponding to a single cell of 1 degree by 1 degree

Supported file transfer protocols
- This model decoder supports all transfer protocols that are supported by the inputStreamFactory of this decoder.
Model structure
- This model decoder creates a model per DTED file.
- All models returned by this model decoder implement ILcd2DBoundsIndexedModel.
Model descriptor
- All models returned by this model decoder have a TLcdDTEDModelDescriptor.
- The type name of the model descriptor is the display name of this decoder.
Model reference
- All models returned by this model decoder have instances of ILcdGeodeticReference as model references.
- The geodetic datum of this reference is an ellipsoidal datum WGS72 or WGS84, or, if supportGeoidDatums is set to true, the more accurate geoid datum EGM96. Alternatively, if applyGeoidDatums is set to true, the geoid height is already added to the elevations of the rasters, and the geodetic datum is WGS84.
Model elements
- Each decoded model contains one object: an ALcdImage (and ILcdRaster) instance.
- The ILcdRaster instance in turn contains a single TLcdDTEDTile instance that corresponds to the DTED cell and that points to additional information about the cell.
- The decoded elevation data is always point-sampled. This is however only exposed via the ALcdImage interface. Legacy rasters are assumed to be area-sampled.
Useful settings
- The property colorModel allows to override the default 16-bits index color that is attached to the decoded rasters, since DTED files don't contain any color information.
- The decoded raster contains the elevation values from the corresponding DTED cell. By default, the rasters contain tiles with piece-wise constant pixel values, without any interpolation (sometimes referred to as "Pixel-is-Area"). However, the original DTED cells contain discrete sample points (sometimes referred to as "Pixel-is-Point"). The way in which a tile value is derived from the DTED can be specified by means of the sampleStrategy property. For instance, a tile value can be a corner value, or the minimum, maximum, or average of the four corner values. Furthermore, the raster values can be derived by means of bilinear interpolation. This yields better-looking results, at a higher computational cost.
Sample code
```
 TLcdDTEDModelDecoder decoder = new TLcdDTEDModelDecoder();

 ILcdModel model = decoder.decode("dted/e011/n45.dt0");
 
```
Performance tips
- It is more efficient to use a single large (multilevel) DMED/DTED raster decoded with TLcdDMEDModelDecoder or TLcdDTEDDirectoryModelDecoder than to use several individual DTED rasters decoded with this decoder.
Thread safety
- The decoding of models is thread-safe, as long as no properties are changed during the decoding.
- The decoded models and elements are thread-safe for read access, on the condition that a thread-safe buffer is used.
Supported versions and specifications
- MIL-D-89020B, Digital Terrain Elevation Data (DTED), NIMA, 23 May 2000
See Also:

TLcdDMEDModelDecoder, TLcdDTEDDirectoryModelDecoder

File	Required	Entry point	Description
*.dt[012]	x	x	DTED file corresponding to a single cell of 1 degree by 1 degree

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`AVERAGE` The sampling strategy that returns the average value of the corners of each DTED sample cell.
`static int`	`BILINEAR` The sampling strategy that returns a bilinear interpolation of the values of the corners of each DTED sample cell.
`static String`	`DEFAULT_DISPLAY_NAME`
`static String[]`	`DEFAULT_EXTENSIONS`
`static int`	`MAXIMUM` The sampling strategy that returns the maximum value of the corners of each DTED sample cell.
`static int`	`MINIMUM` The sampling strategy that returns the minimum value of the corners of each DTED sample cell.
`static int`	`NORTH_EAST_CORNER` The sampling strategy that returns the North-East corner of each DTED sample cell.
`static int`	`NORTH_WEST_CORNER` The sampling strategy that returns the North-West corner of each DTED sample cell.
`static String`	`SHADING_DISPLAY_NAME`
`static int`	`SOUTH_EAST_CORNER` The sampling strategy that returns the South-East corner of each DTED sample cell.
`static int`	`SOUTH_WEST_CORNER` The sampling strategy that returns the South-West corner of each DTED sample cell.

Constructor Summary

Constructors
Constructor and Description
`TLcdDTEDModelDecoder()` Creates a model decoder to decode DTED files, with a globally shared buffer for caching tiles.
`TLcdDTEDModelDecoder(ILcdBuffer aBuffer)` Creates a model decoder to decode DTED files.
`TLcdDTEDModelDecoder(ILcdBuffer aBuffer, boolean aShading)` Creates a model decoder to decode DTED files, optionally producing shaded rasters instead of elevation rasters.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`canDecodeSource(String aString)` Checks whether this model decoder can decode the specified data source.
`ILcdModel`	`decode(String aSourceName)` Creates a new model from the given data source.
`TLcdModelMetadata`	`decodeModelMetadata(String aSourceName)` Decodes metadata for the specified DTED file.
`ColorModel`	`getColorModel()` Returns the color model that is attached to decoded rasters.
`String`	`getDisplayName()` Returns a short, displayable name for the format that is decoded by this `ILcdModelDecoder`.
`ILcdInputStreamFactory`	`getInputStreamFactory()` Returns the input stream factory that is used for creating input streams given source names.
`int`	`getSampleStrategy()`
`boolean`	`isApplyGeoidDatums()`
`boolean`	`isSupportGeoidDatums()`
`void`	`setApplyGeoidDatums(boolean aApplyGeoidDatums)` Specifies whether the geoid heights of the geodetic datum (EGM96) should be added to the elevation data right away while decoding.
`void`	`setColorModel(ColorModel aColorModel)` Sets the color model that will be attached to decoded rasters.
`void`	`setInputStreamFactory(ILcdInputStreamFactory aInputStreamFactory)` Sets the input stream factory that will be used for creating input streams given source names.
`void`	`setSampleStrategy(int aSampleStrategy)` Sets the sampling strategy for retrieving elevation values.
`void`	`setSupportGeoidDatums(boolean aSupportGeoidDatums)` Specifies whether the decoded geodetic datum of the geodetic reference should be a geoid datum (EGM96), instead of the default ellipsoid datum (WGS84 or WGS72).

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.luciad.model.ILcdModelDecoder
canDecodeSource, decodeModelMetadata, decodeSource, discoverDataSources

- Field Detail
  - DEFAULT_DISPLAY_NAME
```
public static final String DEFAULT_DISPLAY_NAME
```
    See Also:
    
    Constant Field Values
  - SHADING_DISPLAY_NAME
```
public static final String SHADING_DISPLAY_NAME
```
    See Also:
    
    Constant Field Values
  - DEFAULT_EXTENSIONS
```
public static final String[] DEFAULT_EXTENSIONS
```
  - NORTH_WEST_CORNER
```
public static final int NORTH_WEST_CORNER
```
    The sampling strategy that returns the North-West corner of each DTED sample cell.
    
    See Also:
    
    Constant Field Values
  - SOUTH_WEST_CORNER
```
public static final int SOUTH_WEST_CORNER
```
    The sampling strategy that returns the South-West corner of each DTED sample cell.
    
    See Also:
    
    Constant Field Values
  - NORTH_EAST_CORNER
```
public static final int NORTH_EAST_CORNER
```
    The sampling strategy that returns the North-East corner of each DTED sample cell.
    
    See Also:
    
    Constant Field Values
  - SOUTH_EAST_CORNER
```
public static final int SOUTH_EAST_CORNER
```
    The sampling strategy that returns the South-East corner of each DTED sample cell.
    
    See Also:
    
    Constant Field Values
  - MINIMUM
```
public static final int MINIMUM
```
    The sampling strategy that returns the minimum value of the corners of each DTED sample cell.
    
    See Also:
    
    Constant Field Values
  - MAXIMUM
```
public static final int MAXIMUM
```
    The sampling strategy that returns the maximum value of the corners of each DTED sample cell.
    
    See Also:
    
    Constant Field Values
  - AVERAGE
```
public static final int AVERAGE
```
    The sampling strategy that returns the average value of the corners of each DTED sample cell.
    
    See Also:
    
    Constant Field Values
  - BILINEAR
```
public static final int BILINEAR
```
    The sampling strategy that returns a bilinear interpolation of the values of the corners of each DTED sample cell.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - TLcdDTEDModelDecoder
```
public TLcdDTEDModelDecoder()
```
    Creates a model decoder to decode DTED files, with a globally shared buffer for caching tiles.
    
    See Also:
    
    TLcdSharedBuffer.getBufferInstance()
  - TLcdDTEDModelDecoder
```
public TLcdDTEDModelDecoder(ILcdBuffer aBuffer)
```
    Creates a model decoder to decode DTED files.
    
    Parameters:
    
    aBuffer - the buffer in which decoded raster tiles are cached.
  - TLcdDTEDModelDecoder
```
public TLcdDTEDModelDecoder(ILcdBuffer aBuffer,
                            boolean aShading)
```
    Creates a model decoder to decode DTED files, optionally producing shaded rasters instead of elevation rasters.
    
    Parameters:
    
    aBuffer - the buffer in which decoded raster tiles are cached.
    
    aShading - specifies whether rasters should be shaded.
- Method Detail
  - setInputStreamFactory
```
public void setInputStreamFactory(ILcdInputStreamFactory aInputStreamFactory)
```
    Sets the input stream factory that will be used for creating input streams given source names.
    
    Specified by:
    
    setInputStreamFactory in interface ILcdInputStreamFactoryCapable
    
    Parameters:
    
    aInputStreamFactory - the input stream factory to be used.
  - getInputStreamFactory
```
public ILcdInputStreamFactory getInputStreamFactory()
```
    Returns the input stream factory that is used for creating input streams given source names.
    
    Specified by:
    
    getInputStreamFactory in interface ILcdInputStreamFactoryCapable
    
    Returns:
    
    the input stream factory that is used.
  - setColorModel
```
public void setColorModel(ColorModel aColorModel)
```
    Sets the color model that will be attached to decoded rasters.
    
    Parameters:
    
    aColorModel - a 16-bit IndexColorModel.
  - getColorModel
```
public ColorModel getColorModel()
```
    Returns the color model that is attached to decoded rasters.
  - setSampleStrategy
```
public void setSampleStrategy(int aSampleStrategy)
```
    Sets the sampling strategy for retrieving elevation values. This setting is only relevant when accessing the DTED model via the ILcdRaster API. The ALcdImage API explicitly models DTED data as being point-sampled and will ignore this setting.
    
    Parameters:
    
    aSampleStrategy - one of NORTH_WEST_CORNER, SOUTH_WEST_CORNER, NORTH_EAST_CORNER, SOUTH_EAST_CORNER, MINIMUM, MAXIMUM, AVERAGE, or BILINEAR.
  - getSampleStrategy
```
public int getSampleStrategy()
```
  - setSupportGeoidDatums
```
public void setSupportGeoidDatums(boolean aSupportGeoidDatums)
```
    Specifies whether the decoded geodetic datum of the geodetic reference should be a geoid datum (EGM96), instead of the default ellipsoid datum (WGS84 or WGS72). The geoid varies smoothly between -110m and +90m around the ellipsoid. The geoid datum is more accurate, but it requires more memory and more processing time when it is being used in transformation calculations.
    The default value is false.
  - isSupportGeoidDatums
```
public boolean isSupportGeoidDatums()
```
  - setApplyGeoidDatums
```
public void setApplyGeoidDatums(boolean aApplyGeoidDatums)
```
    Specifies whether the geoid heights of the geodetic datum (EGM96) should be added to the elevation data right away while decoding. The geoid varies smoothly between -110m and +90m around the ellipsoid. The geodetic datum of the geodetic reference will then be an ordinary ellipsoid datum (WGS84 or WGS72). Decoded rasters will be more accurate, but the operation requires more memory and more processing time while decoding the elevation data (which is still done lazily).
    This is an alternative to setSupportGeoidDatums(boolean). It has precedence if both options are set.
    Note that the 0m elevation (sea level) becomes the geoid height, which may be confusing when a raster is displayed with an elevation color model that assigns blue colors to negative elevations.
    The default is false.
  - isApplyGeoidDatums
```
public boolean isApplyGeoidDatums()
```
  - getDisplayName
```
public String getDisplayName()
```
    Description copied from interface: ILcdModelDecoder
    
    Returns a short, displayable name for the format that is decoded by this ILcdModelDecoder.
    
    Specified by:
    
    getDisplayName in interface ILcdModelDecoder
    
    Returns:
    
    the displayable name of this ILcdModelDecoder.
  - canDecodeSource
```
public boolean canDecodeSource(String aString)
```
    Description copied from interface: ILcdModelDecoder
    
    Checks whether this model decoder can decode the specified data source. It is acceptable for this method to return true for a source name while decode throws an exception for that same source name.
    For performance reasons, we strongly recommend that this will only be a simple test. For example: check the file extension of a file, but not that the file exists or contains expected content.
    
    Specified by:
    
    canDecodeSource in interface ILcdModelDecoder
    
    Parameters:
    
    aString - the data source to be verified; typically a file name or a URL.
    
    Returns:
    
    true if file name aString has extension "dt0", "dt1", "dt2", "dted", "avg", "min", or "max".
    
    See Also:
    
    ILcdModelDecoder.decode(String), ILcdModelDecoder.decodeModelMetadata(String)
  - decode
```
public ILcdModel decode(String aSourceName)
                 throws IOException
```
    Description copied from interface: ILcdModelDecoder
    
    Creates a new model from the given data source.
    Specified by:
    
    decode in interface ILcdModelDecoder
    
    Parameters:
    
    aSourceName - the data source to be decoded; typically a file name or a URL.
    
    Returns:
    
    A model containing the decoded data. While null is allowed, implementors are advised to throw an error instead.
    
    Throws:
    IOException - for any exceptions caused by IO problems or invalid data. Since decoding invalid data almost always results in RunTimeExceptions (NullPointerException, IndexOutOfBoundsException, IllegalArgumentException, ...) on unexpected places, implementations are advised to catch RuntimeExceptions in their decode() method, and wrap them into an IOException, as illustrated in the code snippet below.
    public ILcdModel decode( String aSourceName ) throws IOException { try (InputStream input = fInputStreamFactory.createInputStream(aSourceName)) { // Perform decoding ... } catch (RuntimeException e) { throw new IOException(e); } }
    InterruptedIOException - When the thread on which this method is called is interrupted: it is recommended to stop the decoding and throw an InterruptedIOException. This same exception can also be used if the decoder shows UI to the user, and the user cancels the decoding through the UI.
    
    See Also:
    
    ILcdModelDecoder.canDecodeSource(String)
  - decodeModelMetadata
```
public TLcdModelMetadata decodeModelMetadata(String aSourceName)
                                      throws IOException
```
    Decodes metadata for the specified DTED file. If the DTED file follows the standard DTED naming conventions, this method does not do any I/O, as all metadata can be extracted from the file's source name alone. If that is not the case, this method will attempt to read the file header in order to retrieve its metadata.
    
    Specified by:
    
    decodeModelMetadata in interface ILcdModelDecoder
    
    Parameters:
    
    aSourceName - the DTED file for which metadata will be decoded.
    
    Returns:
    
    the model metadata for the given DTED file.
    
    Throws:
    
    IOException - if the metadata cannot be decoded for some reason.
    
    See Also:
    
    ILcdModelDecoder.canDecodeSource(String)

LuciadLightspeedClass TLcdDTEDModelDecoder

Input files

Supported file transfer protocols

Model structure

Model descriptor

Model reference

Model elements

Useful settings

Sample code

Performance tips

Thread safety

Supported versions and specifications

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface com.luciad.model.ILcdModelDecoder

Field Detail

DEFAULT_DISPLAY_NAME

SHADING_DISPLAY_NAME

DEFAULT_EXTENSIONS

NORTH_WEST_CORNER

SOUTH_WEST_CORNER

NORTH_EAST_CORNER

SOUTH_EAST_CORNER

MINIMUM

MAXIMUM

AVERAGE

BILINEAR

Constructor Detail

TLcdDTEDModelDecoder

TLcdDTEDModelDecoder

TLcdDTEDModelDecoder

Method Detail

setInputStreamFactory

getInputStreamFactory

setColorModel

getColorModel

setSampleStrategy

getSampleStrategy

setSupportGeoidDatums

isSupportGeoidDatums

setApplyGeoidDatums

isApplyGeoidDatums

getDisplayName

canDecodeSource

decode

decodeModelMetadata