org.envirocar.wps.util.BasicStats.java Source code

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Here is the source code for org.envirocar.wps.util.BasicStats.java

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/**
 * Copyright (C) ${year}
 * by 52 North Initiative for Geospatial Open Source Software GmbH
 *
 * Contact: Andreas Wytzisk
 * 52 North Initiative for Geospatial Open Source Software GmbH
 * Martin-Luther-King-Weg 24
 * 48155 Muenster, Germany
 * info@52north.org
 *
 * This program is free software; you can redistribute and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation.
 *
 * This program is distributed WITHOUT ANY WARRANTY; even without the implied
 * WARRANTY OF MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program (see gnu-gpl v2.txt). If not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA or
 * visit the Free Software Foundation web page, http://www.fsf.org.
 */
package org.envirocar.wps.util;

import java.text.ParseException;
import java.util.Date;

import org.envirocar.wps.util.EnviroCarWpsConstants.FeatureProperties;
import org.opengis.feature.simple.SimpleFeature;

import com.fasterxml.jackson.databind.util.ISO8601DateFormat;

/**
 * contains basic methods for calculating statistics for tracks/features
 * 
 * @author staschc
 * 
 */
public class BasicStats {

    /**
     * calculates acceleration (delta_speed/delta_time in m/s^2) between two single
     * track measurements, represented as Geotools simple features
     * 
     * 
     * @param feat1
     *            first track measurement (must be temporally before second)
     * @param feat2
     *            second track measurement
     * @return acceleration between first and second measurement
     * @throws ParseException 
     */
    public static double calculateAcceleration(SimpleFeature feat1, SimpleFeature feat2) throws ParseException {
        double acceleration = 0;

        //compute delta t in seconds
        ISO8601DateFormat df = new ISO8601DateFormat();
        Date timeStart = df.parse((String) feat1.getAttribute(FeatureProperties.TIME));
        Date timeEnd = df.parse((String) feat2.getAttribute(FeatureProperties.TIME));
        long delta_t = (timeEnd.getTime() - timeStart.getTime()) * 1000;

        //compute delta speed in m/s
        double delta_speed = 0;
        Object spo1 = feat1.getAttribute(FeatureProperties.SPEED);
        Object spo2 = feat2.getAttribute(FeatureProperties.SPEED);

        //compute delta speed in km/h
        if (spo1 != null && spo2 != null) {
            double speed1 = Double.parseDouble((String) spo1);
            double speed2 = Double.parseDouble((String) spo2);
            if (speed2 > speed1) {
                delta_speed = speed2 - speed1;
            }
        }

        //convert to m/s
        delta_speed = delta_speed * 0.278;

        //compute acceleration in m/s^2
        acceleration = delta_speed / delta_t;

        return acceleration;
    }

}