Package noaa.coastwatch.io

Class TSHDFReader

java.lang.Object

noaa.coastwatch.io.EarthDataReader

noaa.coastwatch.io.HDFReader

noaa.coastwatch.io.TSHDFReader

All Implemented Interfaces:

HDFSD

public class TSHDFReader
extends HDFReader

A TSHDFReader reads SeaSpace TeraScan HDF format files using the HDF library class. TeraScan HDF files are created using the TeraScan command 'tdftohdf'. This class has been tested using TeraScan versions 3.1 and 3.2 -- see the SeaSpace web site for information on TeraScan and current versions.

Currently only a subset of TeraScan datasets are supported. In particular:

• Sensor scan data with pre-computed double precision latitude and longitude variables in degrees.
• Mapped projection data in 'mercator', 'emercator', 'polarstereo', and 'rectangular' projections. The spheroid used is detected automatically from the TeraScan spheroid parameters.

When a TeraScan HDF dataset is accessed, only attributes that are required by the reader class are actually read -- for example the date and time information, the projection, the variable scaling factors, and so on. Other TeraScan user-defined attributes are ignored. To make up for this problem, there is a mechanism that forces the user-defined attributes to be read into the attribute maps held by the reader (accessed via EarthDataReader.getInfo().getMetadataMap()) and by the variables (accessed by DataVariable.getMetadataMap()). If the user defines a string attribute named import_atts (using setattr for example) which contains a slash-separated list of attribute names, then those attributes listed will be imported into the metadata maps. The import_atts attribute can be defined for a dataset, or for a variable and it will be handled accordingly. This mechanism allows tools like cwimport to import attributes from TeraScan-produced datasets and preserve the user-defined attributes that are of value to the user.

Since:

3.1.0

Author:

Peter Hollemans

Field Summary

Fields

Modifier and Type	Field	Description
static final double	SWATH_POLY_SIZE	Swath polynomial size in kilometers.

Fields inherited from class noaa.coastwatch.io.HDFReader

sdid

Fields inherited from class noaa.coastwatch.io.EarthDataReader

dataProjection, info, rawMetadataMap, variables

Constructor Summary

Constructors

Constructor	Description
TSHDFReader(String file)	Constructs a TSHDF reader from the specified file.

Method Summary

Modifier and Type	Method	Description
String	getDataFormat()	Gets the data format description.
protected EarthDataInfo	getGlobalInfo()	Reads the earth data info metadata.
DataVariable	getPreview(int index)	Creates a data variable preview.

Methods inherited from class noaa.coastwatch.io.HDFReader

close, getAttribute, getAttribute, getAttributeAsArray, getAttributeAsArray, getAttributes, getAttributes, getChunkLengths, getChunkProducer, getClass, getFilename, getPreviewImpl, getSDID, getUnsigned, getVariable, getVariableDimensions, getVariableNames, readAllMetadata

Methods inherited from class noaa.coastwatch.io.EarthDataReader

canUpdateNavigation, containsVariable, finalize, findVariable, getAllGrids, getAllVariables, getCoordinateSystems, getIndex, getInfo, getName, getPreview, getRawMetadata, getRawMetadata, getSceneTime, getSource, getStatistics, getStatisticsVariables, getVariable, getVariables, getVariablesForSystem, putStatistics, setDataProjection, setUnitsMap, updateNavigation

Methods inherited from class java.lang.Object

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

Field Details

SWATH_POLY_SIZE

public static final double SWATH_POLY_SIZE

Swath polynomial size in kilometers.

See Also:

• Constant Field Values

Constructor Details

TSHDFReader

public TSHDFReader(String file)
            throws IOException

Constructs a TSHDF reader from the specified file.

Parameters:

file - the file name to read.

Throws:

IOException - if an error opening or reading the file metadata.

Method Details

getDataFormat

public String getDataFormat()

Gets the data format description.

Specified by:

getDataFormat in class EarthDataReader

getGlobalInfo

protected EarthDataInfo getGlobalInfo()
                               throws hdf.hdflib.HDFException,
IOException,
NoninvertibleTransformException,
ClassNotFoundException

Description copied from class: HDFReader

Reads the earth data info metadata.

Specified by:

getGlobalInfo in class HDFReader

Returns:

the earth data info object.

Throws:

hdf.hdflib.HDFException - if an error occurred in an HDF routine.

IOException - if an error occurred reading the file metadata.

NoninvertibleTransformException - if the earth transform object could not be initialized.

ClassNotFoundException - if the HDF attribute type is unknown.

getPreview

public DataVariable getPreview(int index)
                        throws IOException

Description copied from class: EarthDataReader

Creates a data variable preview. A preview contains all metadata but no data value array. The preview can be used in a filtering loop to determine if the reading of the variable data is desired, as I/O can be a time-intensive operation.

Overrides:

getPreview in class EarthDataReader

Parameters:

index - the index of the variable to preview. Indexing starts at 0.

Returns:

a data variable object with data value array of length 1.

Throws:

IOException - if the data source had I/O errors.

See Also:

• EarthDataReader.getVariable(int)