Package org.apache.sis.coverage.grid

Class DomainLinearizer

java.lang.Object
org.apache.sis.coverage.grid.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
Version:
1.1
Author:
Martin Desruisseaux (Geomatys)
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 org.opengis.referencing.operation.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:
      org.opengis.referencing.operation.TransformException - if some cell coordinates cannot be computed.

    • apply

      public GridGeometry apply(GridGeometry gg) throws org.opengis.referencing.operation.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:
      org.opengis.referencing.operation.TransformException - if some cell coordinates cannot be computed.