Package noaa.coastwatch.io

Class CommonDataModelNCReader

java.lang.Object

noaa.coastwatch.io.EarthDataReader

noaa.coastwatch.io.NCReader

noaa.coastwatch.io.CommonDataModelNCReader

All Implemented Interfaces:

GridSubsetReader, NCSD

public class CommonDataModelNCReader
extends NCReader

The CommonDataModelNCReader class reads Java NetCDF API accessible datasets and attempts to use any metadata and geographic referencing information that the NetCDF layer provides. If a data variable is found that has two geographic axes but also time and/or level axes, the variable data is expanded to a series of 2D variables by extending the variable name for each non-geographic axis. Datasets must:

• have the same earth transform for all grids, and
• use either a geographic map projection with equally spaced lat/lon intervals, or a swath-style map projection with lat/lon data variables provided (since 3.3.1).

Since:

3.2.0

Author:

Peter Hollemans

Field Summary

Fields inherited from class noaa.coastwatch.io.NCReader

dataset

Fields inherited from class noaa.coastwatch.io.EarthDataReader

dataProjection, info, rawMetadataMap, variables

Constructor Summary

Constructors

Constructor	Description
CommonDataModelNCReader(String name)	Creates a new reader from the specified file.

Method Summary

Modifier and Type	Method	Description
protected DataVariable	getActualVariable(int index)	Gets the actual variable with data.
ChunkProducer	getChunkProducer(String name)	Creates a chunk producer for the specified variable.
String	getDataFormat()	Gets the data format description.
Grid	getGridSubset(String varName, int[] start, int[] stride, int[] length)	Reads a subset of a data grid.
protected DataVariable	getPreviewImpl(int index)	Implementation for the subclass.
Map<String,Object>	getRawMetadata(int index)	Gets the detailed raw metadata for a variable.
protected void	initializeReader()	Performs reader initialization after the dataset has been opened.

Methods inherited from class noaa.coastwatch.io.NCReader

close, convertAttributeValue, getAttribute, getAttribute, getAttribute, getAttributeAsArray, getAttributeAsArray, getAttributeAsArray, getCoordinateSystems, getDataset, getFilename, getReferencedFile, getVariable, getVariablesForSystem, isNetwork

Methods inherited from class noaa.coastwatch.io.EarthDataReader

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

Methods inherited from class java.lang.Object

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

Constructor Details

CommonDataModelNCReader

public CommonDataModelNCReader(String name)
                        throws IOException

Creates a new reader from the specified file.

Parameters:

name - the file name or URL to read.

Throws:

IOException - if an error occurred reading the metadata.

Method Details

getDataFormat

public String getDataFormat()

Gets the data format description.

Specified by:

getDataFormat in class EarthDataReader

initializeReader

protected void initializeReader()
                         throws IOException

Description copied from class: NCReader

Performs reader initialization after the dataset has been opened.

Overrides:

initializeReader in class NCReader

Throws:

IOException - if an error occurred on initialization.

getRawMetadata

public Map<String,Object> getRawMetadata(int index)
                                  throws IOException

Description copied from class: EarthDataReader

Gets the detailed raw metadata for a variable.

Overrides:

getRawMetadata in class NCReader

Parameters:

index - the index of the variable for raw metadata.

Returns:

the map of attribute name to attribute value.

Throws:

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

See Also:

• EarthDataReader.getRawMetadata()

getPreviewImpl

protected DataVariable getPreviewImpl(int index)
                               throws IOException

Description copied from class: EarthDataReader

Implementation for the subclass.

Specified by:

getPreviewImpl in class EarthDataReader

Throws:

IOException

See Also:

• EarthDataReader.getPreview(int)

getChunkProducer

public ChunkProducer getChunkProducer(String name)
                               throws IOException

Description copied from class: EarthDataReader

Creates a chunk producer for the specified variable.

Overrides:

getChunkProducer in class EarthDataReader

Parameters:

name - the variable name.

Returns:

a chunk producer for the specified variable.

Throws:

IOException

getActualVariable

protected DataVariable getActualVariable(int index)
                                  throws IOException

Description copied from class: NCReader

Gets the actual variable with data. This method should be implemented in the child class and is only called if the variable is not already in the cache. See NCReader.getVariable(int) for the required behaviour.

Specified by:

getActualVariable in class NCReader

Throws:

IOException

getGridSubset

public Grid getGridSubset(String varName,
 int[] start,
 int[] stride,
 int[] length)
                   throws IOException

Description copied from interface: GridSubsetReader

Reads a subset of a data grid. This is similar to the EarthDataReader.getVariable(String) method except that it reads only grid variables and is capable of returning just a subset of the data values. In some cases, such as across a network connection, it may be more efficient to access only a subset or subsampling of data in a variable.

Specified by:

getGridSubset in interface GridSubsetReader

Overrides:

getGridSubset in class NCReader

Parameters:

varName - the variable name to access.

start - the 2D starting data coordinates.

stride - the 2D data stride.

length - the total number of values to read in each dimension.

Returns:

the subset and/or subsampled grid variable.

Throws:

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