Package org.geotools.process.raster

Class MarchingSquaresVectorizer

Object
MarchingSquaresVectorizer
public final class MarchingSquaresVectorizer extends Object
Algorithm computing the image footprint. Some optimizations are made. When running along the image perimeter, whenever a closed polygon is found, the inner area is filled to make sure we won't analyze that.

It can deal with GridCoverage2D instances, returning footprint in real world coordinates, as well as with RenderedImage instances, returning footprint in raster space coordinates

Author:
Daniele Romagnoli, GeoSolutions SAS, Simone Giannecchini, GeoSolutions SAS, Andrea Aime, GeoSolutions SAS

  • Field Details

    • DEFAULT_RANGES

      public static final List<Range<Integer>> DEFAULT_RANGES

    • DEFAULT_SIMPLIFIER_FACTOR

      public static final double DEFAULT_SIMPLIFIER_FACTOR
      See Also:

    • DEFAULT_THRESHOLD_AREA

      public static final double DEFAULT_THRESHOLD_AREA
      See Also:

  • Constructor Details

    • MarchingSquaresVectorizer

      public MarchingSquaresVectorizer(GridCoverage2D inGeodata, RenderingHints hints, double thresholdArea, double simplifierFactor, MarchingSquaresVectorizer.ImageLoadingType imageLoadingType, List<Range<Integer>> exclusionLuminanceRanges)
      Main Constructor using GridCoverage2D as input.
      Parameters:
      inGeodata - the input GridCoverage2D
      hints - hints to be used by inner processing, it usually contains tile caches, schedulers
      thresholdArea - the minimum area required by a polygon to be included in the result
      simplifierFactor - the simplifier factor to be applied to compute the simplified version of the biggest polygon.
      imageLoadingType - the type of imageLoading (DEFERRED vs IMMEDIATE).
      exclusionLuminanceRanges - the ranges of luminance values to be excluded by the computation.

    • MarchingSquaresVectorizer

      public MarchingSquaresVectorizer(RenderedImage ri, RenderingHints hints, double thresholdArea, MarchingSquaresVectorizer.ImageLoadingType imageLoadingType, List<Range<Integer>> exclusionLuminanceRanges)
      Main Constructor using RenderedImage as input. Returned footprint coordinates will be in raster space.
      Parameters:
      ri - the input RenderedImage
      hints - hints to be used by inner processing, it usually contains tile caches, schedulers
      thresholdArea - the minimum area required by a polygon to be included in the result
      imageLoadingType - the type of imageLoading (DEFERRED vs IMMEDIATE).
      exclusionLuminanceRanges - the range of luminance values to be excluded by the computation.

    • MarchingSquaresVectorizer

      public MarchingSquaresVectorizer()

  • Method Details

    • getRoiShape

      public ROIShape getRoiShape()
      Return the ROIShape version of the footprint after computation

    • getPolygonArea

      public double getPolygonArea()
      Return the area of the simplified footprint after computation

    • getSimplifiedFootprint

      public Geometry getSimplifiedFootprint()
      Return the simplified footprint

    • getFootprint

      public Geometry getFootprint()
      Return the precise footprint

    • setRemoveCollinear

      public void setRemoveCollinear(boolean removeCollinear)
      When set to true (the default) will perform collinear vertices removal

    • setForceValid

      public void setForceValid(boolean forceValid)
      When set to true (the default) will perform extra checks on the output polygons to make sure they are valid geometries

    • setComputeSimplifiedFootprint

      public void setComputeSimplifiedFootprint(boolean computeSimplifiedFootprint)
      When set to true, a simplified version of the footprint will be returned too

    • setImageLoadingType

      public void setImageLoadingType(MarchingSquaresVectorizer.ImageLoadingType imageLoadingType)
      Specifies which type of imageLoading (MarchingSquaresVectorizer.ImageLoadingType) to be used, MarchingSquaresVectorizer.ImageLoadingType.DEFERRED vs MarchingSquaresVectorizer.ImageLoadingType.IMMEDIATE

    • getImageLoadingType

      public MarchingSquaresVectorizer.ImageLoadingType getImageLoadingType()

    • process

      public void process() throws Exception
      Executes the MarchingSquares algorithm to find the footprint.
      Throws:
      Exception

    • areEqual

      public static final boolean areEqual(double value, double pValue)
      Simple check returning where two double values are equal

    • dispose

      public void dispose()

    • getPolygonArea

      public static double getPolygonArea(List<Coordinate> coordinateList)
      Calculates the area of a polygon from the coordinates.
      Returns:
      the area of the polygon.

    • getPolygonArea

      public static double getPolygonArea(int[] x, int[] y, int N)
      Calculates the area of a polygon from its vertices.
      Parameters:
      x - the array of x coordinates.
      y - the array of y coordinates.
      N - the number of sides of the polygon.
      Returns:
      the area of the polygon.

    • createSimplePolygon

      public static Polygon createSimplePolygon(Coordinate[] coords)
      Create a simple polygon (no holes).
      Parameters:
      coords - the coords of the polygon.
      Returns:
      the Polygon.