Module org.apache.sis.referencing
Package org.apache.sis.referencing.operation.transform

Class TransferFunction

Object
TransferFunction
All Implemented Interfaces:
Serializable, Cloneable
public class TransferFunction extends Object implements Cloneable, Serializable
The function converting raster sample values to geophysics values. The function is usually linear, but can sometimes be logarithmic or exponential. The latter occur most often when measuring concentration of something.
Supported transfer function types
TypeEquation
LINEAR y = scale⋅x + offset
LOGARITHMIC y = scale⋅logbase(x) + offset
EXPONENTIAL y = scale⋅basex + offset

Missing values

This Transfer­Function class handles only the continuous part of transfer functions. This class does not handle missing values other than Na­N. For a more complete class with support for non-NaN missing values, see org​.apache​.sis​.coverage​.Sample­Dimension.

Serialization

Serialized instances of this class are not guaranteed to be compatible with future SIS versions. Serialization should be used only for short term storage or RMI between applications running the same SIS version.
Since:
0.5
See Also:

  • Constructor Details

    • TransferFunction

      public TransferFunction()
      Creates a transfer function initialized to the identity transform.
      See Also:

  • Method Details

    • isIdentity

      public boolean isIdentity()
      Returns true if this transfer function is identity. The function is identity if its type is linear, its scale is 1 and its offset is 0.
      Returns:
      whether this transfer function is identity.
      Since:
      1.0

    • getType

      public TransferFunctionType getType()
      Returns the transfer function type (linear, logarithmic or exponential).
      Returns:
      the transfer function type.

    • setType

      public void setType(TransferFunctionType type)
      Sets the transfer function type. The default value is Transfer­Function­Type​.LINEAR.
      Parameters:
      type - the transfer function type.

    • getBase

      public double getBase()
      Returns the logarithm or exponent base in the transfer function. This value is always 1 for Transfer­Function­Type​.LINEAR, and usually (but not necessarily) 10 for the logarithmic and exponential types.
      Returns:
      the logarithmic or exponent base.

    • setBase

      public void setBase(double base)
      Sets the logarithm or exponent base in the transfer function. This value is ignored for Transfer­Function­Type​.LINEAR. For other supported types, the default value is 10.
      Parameters:
      base - the new logarithm or exponent base.
      Throws:
      Illegal­Argument­Exception - if the given base is NaN, negative, zero or infinite.

    • getScale

      public double getScale()
      Returns the scale factor of the transfer function.
      Returns:
      the scale factor.

    • setScale

      public void setScale(double scale)
      Sets the scale factor of the transfer function. The default value is 1.
      Parameters:
      scale - the new scale factor.
      Throws:
      Illegal­Argument­Exception - if the given scale is NaN, zero or infinite.

    • getOffset

      public double getOffset()
      Returns the offset of the transfer function.
      Returns:
      the offset.

    • setOffset

      public void setOffset(double offset)
      Sets the offset of the transfer function. The default value is 0.
      Parameters:
      offset - the new offset.
      Throws:
      Illegal­Argument­Exception - if the given scale is NaN or infinite.

    • createTransform

      public MathTransform createTransform(MathTransformFactory factory) throws FactoryException
      Creates a transform from sample values to geophysics values using the given factory. This method constructs a transform mathematically equivalent to the one returned by get­Transform(), but allows to specify another factory than the default one.
      Parameters:
      factory - the factory to use for creating a transform.
      Returns:
      the transform from sample to geophysics values.
      Throws:
      Factory­Exception - if the given factory failed to create a transform.
      Since:
      1.0

    • getTransform

      public MathTransform1D getTransform()
      Returns the transform from sample values to geophysics values, as specified by the current properties of this Transfer­Function.
      Returns:
      the transform from sample to geophysics values.

    • setTransform

      public void setTransform(MathTransform1D function) throws IllegalArgumentException
      Sets the transform from sample values to geophysics values. This method infers the base, scale and offset values from the given transform.
      Parameters:
      function - the transform to set.
      Throws:
      Illegal­Argument­Exception - if this method does not recognize the given transform.

    • clone

      public TransferFunction clone()
      Returns a clone of this transfer function.
      Overrides:
      clone in class Object
      Returns:
      a clone of this transfer function.
      Since:
      0.8

    • toString

      public String toString()
      Returns a string representation of this transfer function for debugging purpose. The string returned by this method may change in any future SIS version.
      Overrides:
      to­String in class Object
      Returns:
      a string representation of this transfer function.