Package noaa.coastwatch.render

Class ExpressionMaskOverlay

java.lang.Object

noaa.coastwatch.render.EarthDataOverlay

noaa.coastwatch.render.MaskOverlay

noaa.coastwatch.render.ExpressionMaskOverlay

All Implemented Interfaces:

Serializable, Cloneable, Comparable, GridContainerOverlay, TransparentOverlay

public class ExpressionMaskOverlay
extends MaskOverlay
implements GridContainerOverlay

The ExpressionMaskOverlay class uses a mathematical expression to compute a data mask. If the expression evaluates to true or non-zero, then the data is masked, otherwise the data is left visible. An ExpressionMaskOverlay is thus a more general type of BitmaskOverlay.

Since:

3.2.1

Author:

Peter Hollemans

See Also:

• cwmath
• Serialized Form

Field Summary

Fields inherited from class noaa.coastwatch.render.EarthDataOverlay

alpha, lastTrans, prepared

Constructor Summary

Constructors

Constructor	Description
ExpressionMaskOverlay(Color color, EarthDataReader reader, List variableList, String expression)	Constructs a new overlay.

Method Summary

Modifier and Type	Method	Description
String	getExpression()	Gets the current expression.
List<Grid>	getGridList()	Gets the active list of grid variables.
protected boolean	isCompatible(EarthDataView view)	Determines if the data view is compatible with this overlay.
boolean	isMasked(DataLocation loc, boolean isNavigated)	Determines if the data location should be masked.
void	setDataSource(EarthDataReader reader, List variableList)	Sets the data source for grid data.
void	setExpression(String newExpression)	Sets the expression used by the mask.

Methods inherited from class noaa.coastwatch.render.MaskOverlay

createColorModel, draw, getInverse, invalidate, prepare, prepareData, setColor, setInverse, setTransparency

Methods inherited from class noaa.coastwatch.render.EarthDataOverlay

clone, compareTo, getAlphaVersion, getColor, getColors, getColorWithAlpha, getLayer, getMetadataAtPoint, getName, getTransparency, getVisible, hasMetadata, isPrepared, needsPrepare, render, setLayer, setName, setVisible, toString

Methods inherited from class java.lang.Object

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

Constructor Details

ExpressionMaskOverlay

public ExpressionMaskOverlay(Color color,
 EarthDataReader reader,
 List variableList,
 String expression)

Constructs a new overlay. The layer number is initialized to 0.

Parameters:

color - the overlay color.

reader - the reader to use for data variables.

variableList - the list of allowed data variable names.

expression - the mask expression. Variables names in the expression must have corresponding grids in the list.

Method Details

setDataSource

public void setDataSource(EarthDataReader reader,
 List variableList)

Sets the data source for grid data. The reader and variable list must contain data grids with the current set of expression variables.

Specified by:

setDataSource in interface GridContainerOverlay

Parameters:

reader - the reader to use for data variables.

variableList - the list of allowed data variable names.

setExpression

public void setExpression(String newExpression)

Sets the expression used by the mask.

Parameters:

newExpression - the new math expression.

Throws:

IllegalArgumentException - is the expression has a parsing error or contains variables that are not available in the current list of variables.

getExpression

public String getExpression()

Gets the current expression.

isMasked

public boolean isMasked(DataLocation loc,
 boolean isNavigated)

Description copied from class: MaskOverlay

Determines if the data location should be masked.

Specified by:

isMasked in class MaskOverlay

Parameters:

loc - the data location in question.

isNavigated - the navigated flag, true if the data location is pre-navigated

Returns:

true if the data should be masked at the location or false if not.

isCompatible

protected boolean isCompatible(EarthDataView view)

Description copied from class: MaskOverlay

Determines if the data view is compatible with this overlay. If so, then the precomputed view coordinate cache tables will be used to determine data locations for each view point. If not, then each view point is transformed individually using the view's image transform.

Specified by:

isCompatible in class MaskOverlay

Parameters:

view - the data view in question.

Returns:

true if the view has compatible data coordinate caches for the data used to create the mask values in the MaskOverlay.isMasked(noaa.coastwatch.util.DataLocation, boolean) method, or false if not.

getGridList

public List<Grid> getGridList()

Description copied from interface: GridContainerOverlay

Gets the active list of grid variables.

Specified by:

getGridList in interface GridContainerOverlay