org.geotools.feature.visitor
Class StandardDeviationVisitor

Object
  extended by StandardDeviationVisitor
All Implemented Interfaces:
FeatureCalc, FeatureVisitor

public class StandardDeviationVisitor
extends 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.
Module:
modules/library/main (gt-main.jar)

Constructor Summary
StandardDeviationVisitor(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<SimpleFeatureType,SimpleFeature> collection)
           
 void reset()
           
 void visit(Feature feature)
           
 void visit(SimpleFeature feature)
           
 
Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

StandardDeviationVisitor

public StandardDeviationVisitor(Expression expr,
                                double average)
Method Detail

init

public void init(FeatureCollection<SimpleFeatureType,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(SimpleFeature feature)

visit

public void visit(Feature feature)
Specified by:
visit in interface 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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