/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2005-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.filter.function;
import static org.geotools.filter.capability.FunctionNameImpl.*;
import java.io.IOException;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.logging.Level;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.feature.FeatureCollection;
import org.geotools.feature.visitor.CalcResult;
import org.geotools.feature.visitor.QuantileListVisitor;
import org.geotools.filter.capability.FunctionNameImpl;
import org.geotools.util.NullProgressListener;
import org.opengis.filter.capability.FunctionName;
/**
* Breaks a SimpleFeatureCollection into classes with an equal number of items in each.
*
* @author Cory Horner, Refractions Research Inc.
*
*
* @source $URL$
*/
public class QuantileFunction extends ClassificationFunction {
public static FunctionName NAME = new FunctionNameImpl("Quantile",
RangedClassifier.class,
parameter("value", Double.class),
parameter("classes", Integer.class));
public QuantileFunction() {
super(NAME);
}
private Object calculate(SimpleFeatureCollection featureCollection) {
// use a visitor to find the values in each bin
QuantileListVisitor quantileVisit = new QuantileListVisitor(getParameters().get(0), getClasses());
if (progress == null) progress = new NullProgressListener();
try {
featureCollection.accepts(quantileVisit, progress);
} catch (IOException e) {
LOGGER.log(Level.SEVERE, "QuantileFunction calculate(SimpleFeatureCollection) failed" , e);
return null;
}
if (progress.isCanceled()) return null;
CalcResult calcResult = quantileVisit.getResult();
if (calcResult == null) return null;
List[] bin = (List[]) calcResult.getValue();
//generate the min and max values, and round off if applicable/necessary
Comparable globalMin = (Comparable) bin[0].toArray()[0];
Object lastBin[] = bin[bin.length-1].toArray();
if (lastBin.length == 0) {
return null;
}
Comparable globalMax = (Comparable) lastBin[lastBin.length-1];
if ((globalMin instanceof Number) && (globalMax instanceof Number)) {
return calculateNumerical(bin, globalMin, globalMax);
} else {
return calculateNonNumerical(bin);
}
}
private Object calculateNumerical(List[] bin, Comparable globalMin, Comparable globalMax) {
int classNum = bin.length;
//size arrays
Comparable[] localMin = new Comparable[classNum];
Comparable[] localMax = new Comparable[classNum];
//globally consistent
//double slotWidth = (((Number) globalMax).doubleValue() - ((Number) globalMin).doubleValue()) / classNum;
for (int i = 0; i < classNum; i++) {
//copy the min + max values
List thisBin = bin[i];
localMin[i] = (Comparable) thisBin.get(0);
localMax[i] = (Comparable) thisBin.get(thisBin.size()-1);
//locally accurate
double slotWidth = ((Number) localMax[i]).doubleValue() - ((Number) localMin[i]).doubleValue();
if (slotWidth == 0.0) { //use global value, as there is only 1 value in this set
slotWidth = (((Number) globalMax).doubleValue() - ((Number) globalMin).doubleValue()) / classNum;
}
//determine number of decimal places to allow
int decPlaces = decimalPlaces(slotWidth);
decPlaces = Math.max(decPlaces, decimalPlaces(((Number) localMin[i]).doubleValue()));
decPlaces = Math.max(decPlaces, decimalPlaces(((Number) localMax[i]).doubleValue()));
//clean up truncation error
if (decPlaces > -1) {
localMin[i] = new Double(round(((Number) localMin[i]).doubleValue(), decPlaces));
localMax[i] = new Double(round(((Number) localMax[i]).doubleValue(), decPlaces));
}
if (i == 0) {
//ensure first min is less than or equal to globalMin
if (localMin[i].compareTo(new Double(((Number) globalMin).doubleValue())) > 0)
localMin[i] = new Double(fixRound(((Number) localMin[i]).doubleValue(), decPlaces, false));
} else if (i == classNum - 1) {
//ensure last max is greater than or equal to globalMax
if (localMax[i].compareTo(new Double(((Number) globalMax).doubleValue())) < 0)
localMax[i] = new Double(fixRound(((Number) localMax[i]).doubleValue(), decPlaces, true));
}
//synchronize previous max with current min; the ranged classifier is min <= x < y;
if (i != 0){
localMax[i-1] = localMin[i];
}
}
//TODO: disallow having 2 identical bins (ie 0..0, 0..0, 0..0, 0..100)
return new RangedClassifier(localMin, localMax);
}
private Object calculateNonNumerical(List[] bin) {
int classNum = bin.length;
//it's a string.. leave it be (just copy the values)
Set[] values = new Set[classNum];
for (int i = 0; i < classNum; i++) {
values[i] = new HashSet();
Iterator iterator = bin[i].iterator();
while (iterator.hasNext()) {
values[i].add(iterator.next());
}
}
return new ExplicitClassifier(values);
// alternative for ranged classifier
// localMin[i] = (Comparable) thisBin.get(0);
// localMax[i] = (Comparable) thisBin.get(thisBin.size()-1);
}
public Object evaluate(Object feature) {
if (!(feature instanceof FeatureCollection)) {
return null;
}
return calculate((SimpleFeatureCollection) feature);
}
}