Package noaa.coastwatch.io

Class OpendapGrid

java.lang.Object

noaa.coastwatch.util.MetadataContainer

noaa.coastwatch.util.DataVariable

noaa.coastwatch.util.Grid

noaa.coastwatch.io.OpendapGrid

All Implemented Interfaces:

Cloneable, ValueSource

public class OpendapGrid
extends Grid

The OpendapGrid is an intelligent OPeNDAP client that delivers data by listening for DataVariable.setAccessHint(int[], int[], int[]) calls and only downloads the data which is specified within that call.

Since:

3.2.1

Author:

Peter Hollemans

Nested Class Summary

Nested classes/interfaces inherited from class noaa.coastwatch.util.DataVariable

DataVariable.AccessType

Field Summary

Fields inherited from class noaa.coastwatch.util.Grid

COL, COLS, ROW, ROWS

Fields inherited from class noaa.coastwatch.util.DataVariable

data, dims, isUnsigned, lookup, unsignedType

Constructor Summary

Constructors

Constructor	Description
OpendapGrid(Grid grid, String url)	Creates a new grid.

Method Summary

Modifier and Type	Method	Description
Object	getData()	Gets the variable data array.
Object	getData(int[] start, int[] count)	Gets a subset of grid data values.
double	getValue(int index)	Reads a scaled data value.
double	getValue(int row, int col)	Reads a scaled data value with no navigation.
double	interpolate(DataLocation loc)	Reads an interpolated data value.
void	setAccessHint(int[] start, int[] end, int[] stride)	Sets a hint to the variable that subsequent data access will only read/write values within the specified data extents.
void	setValue(int index, double val)	Writes a scaled data value.
void	setValue(int row, int col, double val)	Writes a scaled data value with no navigation.
void	setValue(DataLocation loc, double val)	Writes a scaled data value with navigation.

Methods inherited from class noaa.coastwatch.util.Grid

arraycopy, checkSubset, getNavigation, getSubset, getTilingScheme, getValue, main, navigate, setData, setNavigation

Methods inherited from class noaa.coastwatch.util.DataVariable

convertUnits, dispose, format, format, format, getClassBits, getDataClass, getDecimals, getDimensions, getFormat, getLongName, getMissing, getName, getOptimalStride, getRank, getScaling, getStatistics, getStatistics, getStatistics, getStatistics, getUnits, getUnsigned, getValue, getValues, setAccessType, setData, setFormat, setLongName, setLookup, setMissing, setName, setUnits, setUnsigned, setValue, toString

Methods inherited from class noaa.coastwatch.util.MetadataContainer

clone, getMetadataMap

Methods inherited from class java.lang.Object

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

Constructor Details

OpendapGrid

public OpendapGrid(Grid grid,
 String url)
            throws IOException

Creates a new grid.

Parameters:

grid - the prototype grid upon which to base this one.

url - the OPeNDAP dataset URL to use for data.

Throws:

IOException

Method Details

setAccessHint

public void setAccessHint(int[] start,
 int[] end,
 int[] stride)

Description copied from class: DataVariable

Sets a hint to the variable that subsequent data access will only read/write values within the specified data extents. This method performs no action in the abstract class, but may be used by subclasses that wish to setup internal structures prior to some sort of intensive data access. For example, if data rendering is to occur, it might be useful to read in only the data that will be rendered and make it availalble.

Overrides:

setAccessHint in class DataVariable

Parameters:

start - the starting data coordinates.

end - the ending data coordinates.

stride - the data stride along each dimension.

setValue

public void setValue(int row,
 int col,
 double val)

Description copied from class: Grid

Writes a scaled data value with no navigation. The data value is scaled according to the scaling factor and offset and written to the data array. No navigation transform is applied to correct the data location.

Overrides:

setValue in class Grid

Parameters:

row - the data location row.

col - the data location column.

val - the data value as a double. If the data value is Double.NaN and the missing value is non-null, the missing value is written to the array.

See Also:

• Grid.setValue(DataLocation,double)

setValue

public void setValue(DataLocation loc,
 double val)

Description copied from class: Grid

Writes a scaled data value with navigation. The data value is scaled according to the scaling factor and offset and written to the data array. The navigation transform is applied to correct the data location prior to writing the data value.

Overrides:

setValue in class Grid

Parameters:

loc - the data location. If the location does not navigate to a valid data coordinate, no value is written.

val - the data value as a double. If the data value is Double.NaN and the missing value is non-null, the missing value is written to the array.

See Also:

• Grid.setValue(int,int,double)

setValue

public void setValue(int index,
 double val)

Description copied from class: DataVariable

Writes a scaled data value. The data value is scaled according to the scaling factor and offset and written to the data array.

Overrides:

setValue in class DataVariable

Parameters:

index - the index into the data array.

val - the data value as a double. If the data value is Double.NaN and the missing value is non-null, the missing value is written to the array.

See Also:

• DataVariable.setValue(DataLocation,double)

interpolate

public double interpolate(DataLocation loc)

Description copied from class: DataVariable

Reads an interpolated data value.

Overrides:

interpolate in class Grid

Parameters:

loc - the data value location.

Returns:

the scaled data value as a double. The Double.NaN value is used if the data value is missing.

See Also:

• DataVariable.getValue(int)
• DataVariable.getValue(DataLocation)

getData

public Object getData()

Description copied from class: DataVariable

Gets the variable data array. The returned data is read-only -- the result of attempting to set values in the data is undefined.

Overrides:

getData in class DataVariable

getData

public Object getData(int[] start,
 int[] count)

Description copied from class: Grid

Gets a subset of grid data values. This method is similar to Grid.getData(int[], int[]), but retrieves only a subset of data values in the raw, unscaled form.

Overrides:

getData in class Grid

Parameters:

start - the subset starting [row, column].

count - the subset dimension [rows, columns].

Returns:

an array containing the unscaled data values.

See Also:

• DataVariable.getData()

getValue

public double getValue(int row,
 int col)

Description copied from class: Grid

Reads a scaled data value with no navigation. The data value is read from the data array and scaled according to the scaling factor and offset. No navigation transform is applied to correct the data location.

Overrides:

getValue in class Grid

Parameters:

row - the data location row.

col - the data location column.

Returns:

the scaled data value as a double. The Double.NaN value is used if the data value is missing or data coordinate is not valid.

See Also:

• Grid.getValue(DataLocation)

getValue

public double getValue(int index)

Description copied from class: DataVariable

Reads a scaled data value. The data value is read from the data array and scaled according to the scaling factor and offset.

Overrides:

getValue in class DataVariable

Parameters:

index - the index into the data array.

Returns:

the scaled data value as a double. The Double.NaN value is used if the data value is missing.

See Also:

• DataVariable.getValue(DataLocation)