FESCHatEpsilonReader.java
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package org.orekit.forces.gravity.potential;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.hipparchus.util.FastMath;
import org.hipparchus.util.SinCos;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
/** Reader for ocean tides files following the fes2004.dat format.
* @since 6.1
* @author Luc Maisonobe
*/
public class FESCHatEpsilonReader extends OceanTidesReader {
/** Default pattern for fields with unknown type (non-space characters). */
private static final String UNKNOWN_TYPE_PATTERN = "\\S+";
/** Pattern for fields with integer type. */
private static final String INTEGER_TYPE_PATTERN = "[-+]?\\p{Digit}+";
/** Pattern for fields with real type. */
private static final String REAL_TYPE_PATTERN = "[-+]?(?:(?:\\p{Digit}+(?:\\.\\p{Digit}*)?)|(?:\\.\\p{Digit}+))(?:[eE][-+]?\\p{Digit}+)?";
/** Pattern for fields with Doodson number. */
private static final String DOODSON_TYPE_PATTERN = "\\p{Digit}{2,3}[.,]\\p{Digit}{3}";
/** Pattern for regular data. */
private static final Pattern PATTERN = Pattern.compile("[.,]");
/** Sea water fensity. */
private static final double RHO = 1025;
/** Gravitational constant (from IERS 2010, chapter 1). */
private static final double BIG_G = 6.67428e-11;
/** Earth mean gravity AT EQUATOR (from IERS 2010, chapter 1). */
private static final double GE = 9.7803278;
/** Scale of the CHat parameters. */
private final double scaleCHat;
/** Scale of the epsilon parameters. */
private final double scaleEpsilon;
/** Load deformation coefficients for ocean tides. */
private final OceanLoadDeformationCoefficients oldc;
/** Map for astronomical amplitudes. */
private final Map<Integer, Double> astronomicalAmplitudes;
/** Simple constructor.
* @param supportedNames regular expression for supported files names
* @param scaleCHat scale of the CHat parameters
* @param scaleEpsilon scale of the epsilon parameters
* @param oldc load deformation coefficients for ocean tides
* @param astronomicalAmplitudes map for astronomical amplitudes
* @see AstronomicalAmplitudeReader#getAstronomicalAmplitudesMap()
*/
public FESCHatEpsilonReader(final String supportedNames,
final double scaleCHat, final double scaleEpsilon,
final OceanLoadDeformationCoefficients oldc,
final Map<Integer, Double> astronomicalAmplitudes) {
super(supportedNames);
this.scaleCHat = scaleCHat;
this.scaleEpsilon = scaleEpsilon;
this.oldc = oldc;
this.astronomicalAmplitudes = astronomicalAmplitudes;
}
/** {@inheritDoc} */
@Override
public void loadData(final InputStream input, final String name)
throws IOException {
// FES ocean tides models have the following form:
// Ocean tide model: FES2004 normalized model (fev. 2004) up to (100,100) in cm
// (long period from FES2002 up to (50,50) + equilibrium Om1/Om2, atmospheric tide NOT included)
// Doodson Darw n m Csin+ Ccos+ Csin- Ccos- C+ eps+ C- eps-
// 55.565 Om1 2 0 -0.540594 0.000000 0.000000 0.000000 0.5406 270.000 0.0000 0.000
// 55.575 Om2 2 0 -0.005218 0.000000 0.000000 0.000000 0.0052 270.000 0.0000 0.000
// 56.554 Sa 1 0 0.017233 0.000013 0.000000 0.000000 0.0172 89.957 0.0000 0.000
// 56.554 Sa 2 0 -0.046604 -0.000903 0.000000 0.000000 0.0466 268.890 0.0000 0.000
// 56.554 Sa 3 0 -0.000889 0.000049 0.000000 0.000000 0.0009 273.155 0.0000 0.000
final String[] fieldsPatterns = new String[] {
DOODSON_TYPE_PATTERN,
UNKNOWN_TYPE_PATTERN,
INTEGER_TYPE_PATTERN,
INTEGER_TYPE_PATTERN,
REAL_TYPE_PATTERN,
REAL_TYPE_PATTERN,
REAL_TYPE_PATTERN,
REAL_TYPE_PATTERN,
REAL_TYPE_PATTERN,
REAL_TYPE_PATTERN,
REAL_TYPE_PATTERN,
REAL_TYPE_PATTERN
};
final StringBuilder builder = new StringBuilder("^\\p{Space}*");
for (int i = 0; i < fieldsPatterns.length; ++i) {
builder.append("(");
builder.append(fieldsPatterns[i]);
builder.append(")");
builder.append((i < fieldsPatterns.length - 1) ? "\\p{Space}+" : "\\p{Space}*$");
}
final Pattern regularLinePattern = Pattern.compile(builder.toString());
final double commonFactor = 4 * FastMath.PI * BIG_G * RHO / GE;
final double[] kPrime = oldc.getCoefficients();
// parse the file
startParse(name);
try (BufferedReader r = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8))) {
int lineNumber = 0;
for (String line = r.readLine(); line != null; line = r.readLine()) {
++lineNumber;
final Matcher regularMatcher = regularLinePattern.matcher(line);
if (regularMatcher.matches()) {
// we have found a regular data line
// parse fields
final int doodson = Integer.parseInt(PATTERN.matcher(regularMatcher.group(1)).replaceAll(""));
final int n = Integer.parseInt(regularMatcher.group(3));
final int m = Integer.parseInt(regularMatcher.group(4));
if (canAdd(n, m)) {
final double cHatPlus = scaleCHat * Double.parseDouble(regularMatcher.group(9));
final double ePlus = scaleEpsilon * Double.parseDouble(regularMatcher.group(10));
final double cHatMinus = scaleCHat * Double.parseDouble(regularMatcher.group(11));
final double eMinus = scaleEpsilon * Double.parseDouble(regularMatcher.group(12));
// compute bias from table 6.6
final double hf = astronomicalAmplitudes.getOrDefault(doodson, 0.0);
final int cGamma = doodson / 100000;
final double chiF;
if (cGamma == 0) {
chiF = hf > 0 ? FastMath.PI : 0.0;
} else if (cGamma == 1) {
chiF = hf > 0 ? 0.5 * FastMath.PI : -0.5 * FastMath.PI;
} else if (cGamma == 2) {
chiF = hf > 0 ? 0.0 : FastMath.PI;
} else {
chiF = 0;
}
// compute reference gravity coefficients by converting height coefficients
// IERS conventions 2010, equation 6.21
if (n >= kPrime.length) {
throw new OrekitException(OrekitMessages.OCEAN_TIDE_LOAD_DEFORMATION_LIMITS,
kPrime.length - 1, n, name);
}
final double termFactor = (1 + kPrime[n]) / (2 * n + 1);
// an update on IERS conventions from 2012-08-10 states that for FES model:
// Note that, for zonal terms, FES2004 takes the approach to set
// the retrograde coefficients C-f,nO and S-f,n0 to zero and to double
// the prograde coefficients C+f,nO and S+f,n0. Therefore, after
// applying Equation (6.15), the ΔCn0 have the expected value but the
// ΔSn0 must be set to zero.
// (see ftp://tai.bipm.org/iers/convupdt/chapter6/icc6.pdf)
final SinCos scP = FastMath.sinCos(ePlus + chiF);
final SinCos scM = FastMath.sinCos(eMinus + chiF);
final double cPlus = commonFactor * termFactor * cHatPlus * scP.sin();
final double sPlus = commonFactor * termFactor * cHatPlus * scP.cos();
final double cMinus = (m == 0) ? 0.0 : commonFactor * termFactor * cHatMinus * scM.sin();
final double sMinus = (m == 0) ? 0.0 : commonFactor * termFactor * cHatMinus * scM.cos();
// store parsed fields
addWaveCoefficients(doodson, n, m, cPlus, sPlus, cMinus, sMinus, lineNumber, line);
}
}
}
}
endParse();
}
}