Package ucar.nc2.dataset

Class CoordinateAxis

java.lang.Object
ucar.nc2.CDMNode
ucar.nc2.Variable
ucar.nc2.dataset.VariableDS
ucar.nc2.dataset.CoordinateAxis
All Implemented Interfaces:
Comparable<VariableSimpleIF>, Iterable<Attribute>, IsMissingEvaluator, AttributeContainer, ucar.nc2.dataset.Enhancements, ucar.nc2.dataset.EnhanceScaleMissingUnsigned, VariableEnhanced, ProxyReader, 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.

  • Method Details

    • fromVariableDS

      public static CoordinateAxis.Builder fromVariableDS(VariableDS.Builder<?> vdsBuilder)
      Create a coordinate axis from an existing Variable.Builder.
      Parameters:
      vdsBuilder - an existing Variable in dataset.
      Returns:
      CoordinateAxis or one of its subclasses (CoordinateAxis1D, CoordinateAxis2D, or CoordinateAxis1DTime).

    • copyNoCache

      public CoordinateAxis copyNoCache()
      Make a copy, with an independent cache.
      Returns:
      copy of this CoordinateAxis

    • getAxisType

      public AxisType getAxisType()
      Get type of axis
      Returns:
      type of axis, or null if none.

    • getUnitsString

      public String getUnitsString()
      Description copied from class: Variable
      Get the Unit String for the Variable. Looks for the CDM.UNITS attribute value
      Specified by:
      getUnitsString in interface ucar.nc2.dataset.Enhancements
      Specified by:
      getUnitsString in interface VariableSimpleIF
      Overrides:
      getUnitsString in class VariableDS
      Returns:
      unit string, or null if not found.

    • isNumeric

      public boolean isNumeric()
      Does the axis have numeric values.
      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.

    • isInterval

      public boolean isInterval()
      An interval coordinate consists of two numbers, bound1 and bound2. The coordinate value must lie between them, but otherwise is somewhat arbitrary. If not interval, then it has one number, the coordinate value.
      Returns:
      true if its an interval coordinate.

    • isIndependentCoordinate

      public boolean isIndependentCoordinate()

    • getPositive

      public String getPositive()
      Get the direction of increasing values, used only for vertical Axes.
      Returns:
      POSITIVE_UP, POSITIVE_DOWN, or null if unknown.

    • getBoundaryRef

      public String getBoundaryRef()
      The name of this coordinate axis' boundary variable
      Returns:
      the name of this coordinate axis' boundary variable, or null if none.

    • getMinValue

      public double getMinValue()
      The smallest coordinate value. Only call if isNumeric.
      Returns:
      the minimum coordinate value

    • getMaxValue

      public double getMaxValue()
      The largest coordinate value. Only call if isNumeric.
      Returns:
      the maximum coordinate value

    • getInfo

      public void getInfo(Formatter buf)
      Get a string representation
      Parameters:
      buf - place info here

    • equals

      public boolean equals(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

    • getCalendarFromAttribute

      public Calendar getCalendarFromAttribute()

    • toBuilder

      public CoordinateAxis.Builder<?> toBuilder()
      Description copied from class: Variable
      Turn into a mutable Builder. Can use toBuilder().build() to copy.
      Overrides:
      toBuilder in class VariableDS

    • builder

      public static CoordinateAxis.Builder<?> builder()
      Get Builder for this class that allows subclassing.
      See Also:
      • "https://community.oracle.com/blogs/emcmanus/2010/10/24/using-builder-pattern-subclasses"