Circularity Class Reference

Calculates a circularity score for a given polygon. More...

Inheritance diagram for Circularity:

Collaboration diagram for Circularity:

Public Member Functions
String	getURI ()
double	attribute (Geometry geom)
Value	evaluate (ValueFactory valueFactory, Value... args) throws ValueExprEvaluationException

Detailed Description

Calculates a circularity score for a given polygon.

Member Function Documentation

attribute()

double attribute

(

Geometry

geom

)

Reimplemented from GeometricDoubleAttributeFunction.

                                               {
        if (geom instanceof Polygon) {
                double areasum=0.,perimetersum=0.;
                for(int i=0;i<geom.getNumGeometries();i++) {
                        areasum+=geom.getArea();
                        perimetersum+=geom.getLength();
                }
                return (4*Math.PI*areasum)/(perimetersum*perimetersum);
        }
        return 0.;
        }

evaluate()

Value evaluate ( ValueFactory  valueFactory, Value...  args  ) throws ValueExprEvaluationException

inherited

                                                                                                            {
                if (args.length != 1) {
                        throw new ValueExprEvaluationException(getURI() + " requires exactly 1 arguments, got " + args.length);
                }
 
                LiteralType l=LiteralRegistry.getLiteral(((Literal)args[0]).getDatatype().toString());
                if(l instanceof VectorLiteral) {
                        Geometry geom=((VectorLiteral)l).read(args[0].stringValue());
                        double result = attribute(geom);
                        return valueFactory.createLiteral(result);
                }
                throw new ValueExprEvaluationException("Argument given is not a geometry literal");
 
        }

References GeometricDoubleAttributeFunction.attribute(), and LiteralRegistry.getLiteral().

Referenced by AreaTest.testArea(), CompactnessRatioTest.testCompactnessRatio(), CompactnessRatioTest.testCompactnessRatioNaN(), CircularityTest.testIsScaleneTriangleFalse(), CircularityTest.testIsScaleneTriangleTrue(), LengthTest.testLineString(), MTest.testM(), MinimumBoundingRadiusTest.testMinimumBoundingRadius(), MinimumClearanceTest.testMinimumClearance(), MinimumDiameterTest.testMinimumDiameter(), MaxMTest.testMMax(), MinMTest.testMMin(), PerimeterTest.testPerimeter(), XTest.testX(), MaxXTest.testXMax(), MinXTest.testXMin(), YTest.testY(), MaxYTest.testYMax(), MinYTest.testYMin(), ZTest.testZ(), MaxZTest.testZMax(), and MinZTest.testZMin().

getURI()

String getURI

(

)

                               {
                return POSTGIS.st_circularity.stringValue();
        }

References POSTGIS.st_circularity.