org.geotools.feature.visitor
Class StandardDeviationVisitor

java.lang.Object
  extended by org.geotools.feature.visitor.StandardDeviationVisitor
All Implemented Interfaces:
FeatureCalc, org.opengis.feature.FeatureVisitor

public class StandardDeviationVisitor
extends java.lang.Object
implements FeatureCalc

Determines the standard deviation.

            ----------------------------
            |  1   ---
 Std dev =  | ___  \   ( x - mean ) ^ 2
           \|  N   /__
 
aka std dev = sqrt((sum((x-mean)^2))/N) where N is the number of samples

Author:
Cory Horner, Refractions Research Inc.

Constructor Summary
StandardDeviationVisitor(org.opengis.filter.expression.Expression expr, double average)
           
 
Method Summary
 int getNaNCount()
           
 int getNullCount()
           
 CalcResult getResult()
          Returns the result of the calculation as a handy object which can be merged and modified.
 void init(FeatureCollection<org.opengis.feature.simple.SimpleFeatureType,org.opengis.feature.simple.SimpleFeature> collection)
           
 void reset()
           
 void visit(org.opengis.feature.Feature feature)
           
 void visit(org.opengis.feature.simple.SimpleFeature feature)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

StandardDeviationVisitor

public StandardDeviationVisitor(org.opengis.filter.expression.Expression expr,
                                double average)
Method Detail

init

public void init(FeatureCollection<org.opengis.feature.simple.SimpleFeatureType,org.opengis.feature.simple.SimpleFeature> collection)

getResult

public CalcResult getResult()
Description copied from interface: FeatureCalc
Returns the result of the calculation as a handy object which can be merged and modified.

Specified by:
getResult in interface FeatureCalc
Returns:
the results of the calculation

visit

public void visit(org.opengis.feature.simple.SimpleFeature feature)

visit

public void visit(org.opengis.feature.Feature feature)
Specified by:
visit in interface org.opengis.feature.FeatureVisitor

reset

public void reset()

getNaNCount

public int getNaNCount()
Returns:
the number of features which returned a NaN

getNullCount

public int getNullCount()
Returns:
the number of features which returned a null


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