/*
* Copyright (C) 2012.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 or
* version 2 as published by the Free Software Foundation.
*
* This program 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
* General Public License for more details.
*/
package uk.me.parabola.mkgmap.osmstyle.function;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.util.Locale;
import java.util.Map.Entry;
import uk.me.parabola.imgfmt.app.Coord;
import uk.me.parabola.log.Logger;
import uk.me.parabola.mkgmap.reader.osm.Element;
import uk.me.parabola.mkgmap.reader.osm.Relation;
import uk.me.parabola.mkgmap.reader.osm.Way;
import uk.me.parabola.mkgmap.scan.SyntaxException;
/**
* Calculates the length of a way or a relation in meter. The length of a
* relation is defined as the sum of its member lengths.
*
* @author WanMil
*/
public class LengthFunction extends CachedFunction {
private static final Logger log = Logger.getLogger(LengthFunction.class);
private final DecimalFormat nf = new DecimalFormat("0.0#####################", DecimalFormatSymbols.getInstance(Locale.US));
public LengthFunction() {
super(null);
}
protected String calcImpl(Element el) {
double length = calcLength(el);
return nf.format(length);
}
private double calcLength(Element el) {
if (el instanceof Way) {
Way w = (Way)el;
double length = 0;
Coord prevC = null;
for (Coord c : w.getPoints()) {
if (prevC != null) {
length += prevC.distance(c);
}
prevC = c;
}
return length;
} else if (el instanceof Relation) {
Relation rel = (Relation)el;
double length = 0;
for (Entry<String,Element> relElem : rel.getElements()) {
if (relElem.getValue() instanceof Way || relElem.getValue() instanceof Relation) {
if (rel == relElem.getValue()) {
// avoid recursive call
log.error("Relation "+rel.getId()+" contains itself as element. This is not supported.");
} else {
length += calcLength(relElem.getValue());
}
}
}
return length;
} else {
throw new SyntaxException("length() cannot calculate elements of type "+el.getClass().getName());
}
}
public String getName() {
return "length";
}
public boolean supportsWay() {
return true;
}
public boolean supportsRelation() {
return true;
}
}