ucar.nc2.dataset
Class CoordinateAxis

java.lang.Object
  ucar.nc2.Variable
      ucar.nc2.dataset.VariableDS
          ucar.nc2.dataset.CoordinateAxis

All Implemented Interfaces:

java.lang.Comparable<VariableSimpleIF>, Enhancements, EnhanceScaleMissing, VariableEnhanced, VariableIF, VariableSimpleIF

Direct Known Subclasses:

CoordinateAxis1D, CoordinateAxis2D

public class CoordinateAxis
extends VariableDS

A Coordinate Axis is a Variable that specifies one of the coordinates of a CoordinateSystem. Mathematically it is a scalar function F from index space to S:

  F:D -> S
  where D is a product set of dimensions (aka index space), and S is the set of reals (R) or Strings.
 

If its element type is char, it is considered a string-valued Coordinate Axis and rank is reduced by one, since the outermost dimension is considered the string length: v(i, j, .., strlen). If its element type is String, it is a string-valued Coordinate Axis. Otherwise it is numeric-valued, and isNumeric() is true.

The one-dimensional case F(i) -> R is the common case which affords important optimizations. In that case, use the subtype CoordinateAxis1D. The factory methods will return either a CoordinateAxis1D if the variable is one-dimensional, a CoordinateAxis2D if its 2D, or a CoordinateAxis for the general case.

A CoordinateAxis is optionally marked as georeferencing with an AxisType. It should have a units string and optionally a description string.

A Structure cannot be a CoordinateAxis, although members of Structures can.

Author:

john caron

Nested Class Summary

static class

CoordinateAxis.AxisComparator Standard sort on Coordinate Axes

Field Summary

static java.lang.String	POSITIVE_DOWN
static java.lang.String	POSITIVE_UP

Fields inherited from class ucar.nc2.Variable

defaultSizeToCache

Constructor Summary

CoordinateAxis(NetcdfDataset ds, Group group, java.lang.String shortName, DataType dataType, java.lang.String dims, java.lang.String units, java.lang.String desc)
Constructor when theres no underlying variable.

Method Summary

boolean	equals(java.lang.Object oo) Instances which have same content are equal.
static CoordinateAxis	factory(NetcdfDataset ncd, VariableDS vds) Create a coordinate axis from an existing Variable.
AxisType	getAxisType()
java.lang.String	getBoundaryRef() The name of this coordinate axis' boundary variable
java.lang.String	getInfo()
double	getMaxValue()
double	getMinValue()
java.lang.String	getPositive() Get the direction of increasing values, used only for vertical Axes.
java.lang.String	getUnitsString() Get the Unit String for the Variable.
int	hashCode() Override Object.hashCode() to implement equals.
boolean	isContiguous() If the edges are contiguous or disjoint Caution: many datasets do not explicitly specify this info, this is often a guess; default is true.
boolean	isNumeric()
CoordinateAxis	makeCopy()
void	setAxisType(AxisType axisType) Set type of axis, or null if none.
void	setBoundaryRef(java.lang.String boundaryRef) Set a reference to a boundary variable.
void	setContiguous(boolean isContiguous) Set if the edges are contiguous or disjoint.
void	setPositive(java.lang.String positive) Set the direction of increasing values, used only for vertical Axes.

Methods inherited from class ucar.nc2.dataset.VariableDS

addCoordinateSystem, convertScaleOffsetMissing, convertScaleOffsetMissing, convertScaleOffsetMissing, convertScaleOffsetMissing, convertScaleOffsetMissing, convertScaleOffsetMissing, enhance, getCoordinateSystems, getDescription, getOriginalDataType, getOriginalName, getOriginalVariable, getProxyReader, getUseNaNs, getValidMax, getValidMin, hasFillValue, hasInvalidData, hasMissing, hasMissingValue, hasScaleOffset, isCoordinateVariable, isFillValue, isInvalidData, isMissing, isMissingFast, isMissingValue, removeCoordinateSystem, setFillValueIsMissing, setInvalidDataIsMissing, setMissingDataIsMissing, setName, setOriginalVariable, setProxyReader, setUnitsString, setUseNaNs, toStringDebug

Methods inherited from class ucar.nc2.Variable

addAttribute, compareTo, createNewCache, findAttribute, findAttributeIgnoreCase, findDimensionIndex, getAttributes, getDataType, getDimension, getDimensions, getDimensionsAll, getDimensionsString, getElementSize, getName, getNameAndDimensions, getNameAndDimensions, getNameAndDimensions, getNameAndDimensions, getNameEscaped, getParentGroup, getParentStructure, getRanges, getRank, getShape, getShapeAsSection, getShortName, getSize, getSizeToCache, getSPobject, hasCachedData, invalidateCache, isCaching, isImmutable, isMemberOfStructure, isMetadata, isScalar, isUnknownLength, isUnlimited, isUnsigned, isVariableLength, lookupEnumString, read, read, read, read, read, readScalarByte, readScalarDouble, readScalarFloat, readScalarInt, readScalarLong, readScalarShort, readScalarString, remove, removeAttribute, resetDimensions, resetShape, section, section, setCachedData, setCaching, setDataType, setDimension, setDimensions, setDimensions, setDimensionsAnonymous, setElementSize, setEnumTypedef, setImmutable, setIsScalar, setParentGroup, setParentStructure, setSizeToCache, setSPobject, slice, toString, writeCDL

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface ucar.nc2.VariableIF

findAttribute, findAttributeIgnoreCase, findDimensionIndex, getAttributes, getDataType, getDimension, getDimensions, getDimensionsAll, getElementSize, getName, getNameAndDimensions, getNameEscaped, getParentGroup, getParentStructure, getRanges, getRank, getShape, getShapeAsSection, getShortName, getSize, isMemberOfStructure, isMetadata, isScalar, isUnlimited, isUnsigned, isVariableLength, read, read, read, read, readScalarByte, readScalarDouble, readScalarFloat, readScalarInt, readScalarLong, readScalarShort, readScalarString, section

Methods inherited from interface java.lang.Comparable

compareTo

Field Detail

POSITIVE_UP

public static final java.lang.String POSITIVE_UP

See Also:

Constant Field Values

POSITIVE_DOWN

public static final java.lang.String POSITIVE_DOWN

See Also:

Constant Field Values

Constructor Detail

CoordinateAxis

public CoordinateAxis(NetcdfDataset ds,
                      Group group,
                      java.lang.String shortName,
                      DataType dataType,
                      java.lang.String dims,
                      java.lang.String units,
                      java.lang.String desc)

Constructor when theres no underlying variable. You better set the values too!

Parameters:

ds - the containing dataset.

group - the containing group; if null, use rootGroup

shortName - axis name.

dataType - data type

dims - list of dimension names

units - units of coordinates, preferably udunit compatible.

desc - long name.

Method Detail

factory

public static CoordinateAxis factory(NetcdfDataset ncd,
                                     VariableDS vds)

Create a coordinate axis from an existing Variable.

Parameters:

ncd - the containing dataset

vds - an existing Variable in dataset.

Returns:

CoordinateAxis or one of its subclasses (CoordinateAxis1D, CoordinateAxis2D, or CoordinateAxis1DTime).

makeCopy

public CoordinateAxis makeCopy()

getAxisType

public AxisType getAxisType()

Returns:

type of axis, or null if none.

setAxisType

public void setAxisType(AxisType axisType)

Set type of axis, or null if none. Default is none.

Parameters:

axisType - set to this value

getUnitsString

public java.lang.String getUnitsString()

Description copied from class: Variable

Get the Unit String for the Variable. Looks for the "units" attribute value

Specified by:

getUnitsString in interface Enhancements

Specified by:

getUnitsString in interface VariableIF

Specified by:

getUnitsString in interface VariableSimpleIF

Overrides:

getUnitsString in class VariableDS

Returns:

unit string, or null if not found.

isNumeric

public boolean isNumeric()

Returns:

true if the CoordAxis is numeric, false if its string valued ("nominal").

isContiguous

public boolean isContiguous()

If the edges are contiguous or disjoint Caution: many datasets do not explicitly specify this info, this is often a guess; default is true.

Returns:

true if the edges are contiguous or false if disjoint. Assumed true unless set otherwise.

setContiguous

public void setContiguous(boolean isContiguous)

Set if the edges are contiguous or disjoint.

Parameters:

isContiguous - true if the adjacent edges touch

getPositive

public java.lang.String getPositive()

Get the direction of increasing values, used only for vertical Axes.

Returns:

POSITIVE_UP, POSITIVE_DOWN, or null if unknown.

setPositive

public void setPositive(java.lang.String positive)

Set the direction of increasing values, used only for vertical Axes.

Parameters:

positive - POSITIVE_UP, POSITIVE_DOWN, or null if you dont know..

getBoundaryRef

public java.lang.String getBoundaryRef()

The name of this coordinate axis' boundary variable

Returns:

the name of this coordinate axis' boundary variable, or null if none.

setBoundaryRef

public void setBoundaryRef(java.lang.String boundaryRef)

Set a reference to a boundary variable.

Parameters:

boundaryRef - the name of a boundary coordinate variable in the same dataset.

getMinValue

public double getMinValue()

Returns:

the minimum coordinate value

getMaxValue

public double getMaxValue()

Returns:

the maximum coordinate value

getInfo

public java.lang.String getInfo()

Returns:

formatted string representation

equals

public boolean equals(java.lang.Object oo)

Instances which have same content are equal.

Overrides:

equals in class Variable

hashCode

public int hashCode()

Override Object.hashCode() to implement equals.

Overrides:

hashCode in class Variable