DtcDataLoader.java
/* Copyright 2002-2024 CS GROUP
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* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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package org.orekit.models.earth.atmosphere.data;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Serializable;
import java.nio.charset.StandardCharsets;
import java.text.ParseException;
import java.util.NoSuchElementException;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.regex.Pattern;
import java.util.HashSet;
import java.util.Set;
import org.orekit.data.DataLoader;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.ChronologicalComparator;
import org.orekit.time.TimeScale;
import org.orekit.time.TimeStamped;
import org.orekit.utils.Constants;
/**
* This class reads solar activity data from DTCFILE files for the class
* {@link JB2008SpaceEnvironmentData}. The code in this class is based of the
* CssiSpaceWeatherDataLoader class.
* The DTCFILE file contain pre-computed data from Space Environment using the Dst indices
* as well as Ap indices. This computation can be realised using the Fortran code provided
* by Space Environment Technologies. See <a href="https://sol.spacenvironment.net/JB2008/indices/DTCFILE.TXT">
* this link</a> for more information.
* <p>
* The data is provided by Space Environment Technologies through their website
* <a href="https://sol.spacenvironment.net/JB2008/indices/DTCFILE.TXT">Link</a>.
* </p>
* The work done for this class is based on the CssiSpaceWeatherDataLoader class
* by Clément Jonglez, the JB2008 interface by Pascal Parraud, and corrections for
* DataLoader implementation by Bryan Cazabonne and Evan Ward .
*
* @author Louis Aucouturier
* @since 11.2
*/
public class DtcDataLoader implements DataLoader {
/** Container class for Solar activity indexes. */
public static class LineParameters implements TimeStamped, Serializable {
/** Serializable UID. */
private static final long serialVersionUID = 8239275953453087629L;
/** Entry date. */
private final AbsoluteDate date;
/** dTc temperature correction data. */
private final double dtc;
/**
* Constructor.
* @param date entry date
* @param dtc Temperature correction for geomagnetic storms
*/
public LineParameters(final AbsoluteDate date, final double dtc) {
this.date = date;
this.dtc = dtc;
}
@Override
public AbsoluteDate getDate() {
return date;
}
/**
* Get the DSTDTC parameter.
* <p>
* It represents the temperature correction for geomagnetic storms.
* </p>
* @return dTc Temperature correction for geomagnetic storms
*/
public double getDSTDTC() {
return dtc;
}
}
/** Pattern for regular data. */
private static final Pattern PATTERN_SPACE = Pattern.compile("\\s+");
/** UTC time scale. */
private final TimeScale utc;
/** First available date. */
private AbsoluteDate firstDate;
/** Last available date. */
private AbsoluteDate lastDate;
/** Data set. */
private SortedSet<LineParameters> set;
/**
* Constructor.
* @param utc UTC time scale
*/
public DtcDataLoader(final TimeScale utc) {
this.utc = utc;
firstDate = null;
lastDate = null;
set = new TreeSet<>(new ChronologicalComparator());
}
/**
* Getter for the data set.
* @return the data set
*/
public SortedSet<LineParameters> getDataSet() {
return set;
}
/**
* Gets the available data range minimum date.
* @return the minimum date.
*/
public AbsoluteDate getMinDate() {
return firstDate;
}
/**
* Gets the available data range maximum date.
* @return the maximum date.
*/
public AbsoluteDate getMaxDate() {
return lastDate;
}
/** {@inheritDoc} */
public void loadData(final InputStream input, final String name)
throws IOException, ParseException, OrekitException {
int lineNumber = 0;
String line = null;
final int nHours = 24;
final Set<AbsoluteDate> parsedEpochs = new HashSet<>();
try (BufferedReader br = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8))) {
final CommonLineReader reader = new CommonLineReader(br);
for (line = reader.readLine(); line != null; line = reader.readLine()) {
lineNumber++;
if (!reader.isEmptyLine()) {
/** extract the data from the line
* The data is extracted from substrings as the spacing between
* columns is constant.
*/
/**
* The date is expressed as a year and the day-number in this year.
* Then the dTc is expressed in each column at a different hour, with
* column 4 being the first hour of the day and column 28 the last hour
* of the day.
* Each column is converted to a single LineParameters object.
*/
final String[] splitLine = PATTERN_SPACE.split(line);
final int year = Integer.parseInt(splitLine[1]);
final int dayYear = Integer.parseInt(splitLine[2]);
final AbsoluteDate initDate = new AbsoluteDate(year, 1, 1, utc);
final AbsoluteDate currDate = initDate.shiftedBy((dayYear - 1) * Constants.JULIAN_DAY);
for (int i = 0; i < nHours; i++) {
final AbsoluteDate date = currDate.shiftedBy(3600 * i);
if (parsedEpochs.add(date)) { // Checking if entry doesn't exist yet
final double dtc = Integer.parseInt(splitLine[3 + i]);
set.add(new LineParameters(date, dtc));
}
}
}
}
} catch (NumberFormatException nfe) {
throw new OrekitException(nfe, OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE, lineNumber, name, line);
}
try {
firstDate = set.first().getDate();
lastDate = set.last().getDate();
} catch (NoSuchElementException nse) {
throw new OrekitException(nse, OrekitMessages.NO_DATA_IN_FILE, name);
}
}
/** {@inheritDoc} */
public boolean stillAcceptsData() {
return true;
}
}