Module org.apache.sis.feature
Package org.apache.sis.coverage.grid

Class DomainLinearizer

Object
DomainLinearizer
public class DomainLinearizer extends Object
Method for replacing a non-linear "grid to CRS" conversion by a linear conversion (affine transform). The Grid­Geometry class allows non-linear "grid to CRS" conversions, but some Grid­Geometry usages are restricted to linear (affine) conversions. The Domain­Linearizer class encapsulates the method used for replacing non-linear conversions by a linear approximation.

The same instance can be reused by invoking apply(…) methods for many Grid­Coverage or Grid­Geometry instances.

Limitations

Current implementation is designed for two-dimensional grid geometries. Support for higher dimensions is not guaranteed.
Since:
1.1
See Also:

  • Constructor Details

    • DomainLinearizer

      public DomainLinearizer()
      Creates a new linearizer.

  • Method Details

    • getGridStartsAtZero

      public boolean getGridStartsAtZero()
      Returns whether Grid­Extent should have their lower grid coordinates set to zero. If true, then Domain­Linearizer will opportunistically apply translation on the "grid to CRS" conversion in such a way that Grid­Extent​.get­Low() is 0 for all dimensions.
      Returns:
      whether to force lower grid coordinates to (0,0,…).
      See Also:

    • setGridStartsAtZero

      public void setGridStartsAtZero(boolean force)
      Sets whether Grid­Extent should have their lower grid coordinates set to zero. The default value is false.
      Parameters:
      force - whether to force lower grid coordinates to (0,0,…).

    • getScaleFactor

      public double getScaleFactor()
      Returns the scale factor applied on coordinates in all dimensions.
      Returns:
      scale factor applied on coordinates in all dimensions, or 1 if none.

    • setScaleFactor

      public void setScaleFactor(double factor)
      Sets the scale factor to apply on coordinates in all dimensions. Must be a value greater than zero. The default value is 1.
      Parameters:
      factor - scale factor applied on coordinates in all dimensions, or 1 if none.

    • apply

      public GridCoverage apply(GridCoverage coverage) throws TransformException
      Returns a grid coverage with a linear approximation of the grid to CRS conversion. The linear approximation is computed by apply(Grid­Geometry). If the grid to CRS conversion of the given coverage is already linear, then this method returns coverage.
      Parameters:
      coverage - the grid coverage in which to make the grid to CRS conversion linear.
      Returns:
      a grid coverage with a linear approximation of the grid to CRS conversion.
      Throws:
      Transform­Exception - if some cell coordinates cannot be computed.

    • apply

      public GridGeometry apply(GridGeometry gg) throws TransformException
      Creates a grid geometry with a linear approximation of the grid to CRS conversion. The approximation is computed by Least Mean Squares method: the affine transform coefficients are chosen in way making the average value of (position − linear approximation of position)² as small as possible for all cells in given grid geometry. If the grid to CRS conversion of the given grid geometry is already linear, then this method returns gg.
      Parameters:
      gg - the grid geometry in which to make the grid to CRS conversion linear.
      Returns:
      a grid geometry with a linear approximation of the grid to CRS conversion.
      Throws:
      Transform­Exception - if some cell coordinates cannot be computed.