
GISHullActorJ |
org.ecoinformatics.seek.gis.java_gis.GISHullActorJ |
The purpose of this actor is to take a set of (x, y) points and return the points that define
the convex hull around the input. The convex hull can be thought of as the region defined by
a 'rubber band' placed around the original data set. It is a sort of smallest polygon surrounding
the input. The ConvexHull routine is implemented in Java and is thus portable to any java-enabled
system. This actor is designed to have the same functionality as the JNI basedGISHullActor
'pointFileName' is a tab delimited text file with x,y input points
'hullFileName' is the name to be given to the hull point list file
'numHullPoint' is the number of x,y pairs in the hull file
'hullFileResult' is the output hull file name (same value as the 'hullFileName' but
used as a trigger for output
There is also a 'scaleFactorParameter'. This is the scale factor for an AffineTransformation
of the shape created by the ConvexHull. The convexHull shape is scaled by this factor (linearly),
centered on the center of the convexhull bounding rectangle. The scale by area, set the
scalefactor to the square root of the area scaling factor (i.e. to make a shape with twice the
area, set the scale factor to SQRT(2) )
Note: if the scaleFactorParameter is empty or not a number, no scaling will be done.
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pointFileName
'pointFileName' is a tab delimited text file with x,y input points
hullFileName
'hullFileName' is the name to be given to the hull point list file
numHullPoint
'numHullPoint' is the number of x,y pairs in the hull file
hullFileResult
'hullFileResult' is the output hull file name (same value as the 'hullFileName' but
used as a trigger for output
scaleFactorParameter
This is the scale factor for an AffineTransformation
of the shape created by the ConvexHull. The convexHull shape is scaled by this factor (linearly),
centered on the center of the convexhull bounding rectangle. The scale by area, set the
scalefactor to the square root of the area scaling factor (i.e. to make a shape with twice the
area, set the scale factor to SQRT(2) )