@Test
public void testInterpolationAtEndOfValidity() throws OrekitException {
double decimalYear = GeoMagneticField.getDecimalYear(1, 1, 2020);
GeoMagneticField field = GeoMagneticFieldFactory.getIGRF(decimalYear);
GeoMagneticElements e = field.calculateField(0, 0, 0);
Assert.assertEquals(-4.7446, e.getDeclination(), 1.0e-4);
}
@Test
public void testInterpolationYYY5() throws OrekitException {
double decimalYear = GeoMagneticField.getDecimalYear(1, 1, 2005);
GeoMagneticField field = GeoMagneticFieldFactory.getIGRF(decimalYear);
GeoMagneticElements e = field.calculateField(1.2, 0.7, -2.5);
Assert.assertEquals(-6.0032, e.getDeclination(), 1.0e-4);
decimalYear = GeoMagneticField.getDecimalYear(2, 1, 2005);
field = GeoMagneticFieldFactory.getIGRF(decimalYear);
e = field.calculateField(1.2, 0.7, -2.5);
Assert.assertEquals(-6.0029, e.getDeclination(), 1.0e-4);
}
@Test
public void testWMM() throws Exception {
// test values from sample coordinate file
// provided as part of the geomag 7.0 distribution available at
// http://www.ngdc.noaa.gov/IAGA/vmod/igrf.html
// modification: the julian day calculation of geomag is slightly different
// to the one from the WMM code, we use the WMM convention thus the outputs
// have been adapted.
runSampleFile(FieldModel.WMM, "sample_coords.txt", "sample_out_WMM2015.txt");
final double eps = 1e-1;
final double degreeEps = 1e-2;
for (int i = 0; i < wmmTestValues.length; i++) {
final GeoMagneticField model = GeoMagneticFieldFactory.getWMM(wmmTestValues[i][0]);
final GeoMagneticElements result =
model.calculateField(wmmTestValues[i][2], wmmTestValues[i][3], wmmTestValues[i][1]);
// X
Assert.assertEquals(wmmTestValues[i][4], result.getFieldVector().getX(), eps);
// Y
Assert.assertEquals(wmmTestValues[i][5], result.getFieldVector().getY(), eps);
// Z
Assert.assertEquals(wmmTestValues[i][6], result.getFieldVector().getZ(), eps);
// H
Assert.assertEquals(wmmTestValues[i][7], result.getHorizontalIntensity(), eps);
// F
Assert.assertEquals(wmmTestValues[i][8], result.getTotalIntensity(), eps);
// inclination
Assert.assertEquals(wmmTestValues[i][9], result.getInclination(), degreeEps);
// declination
Assert.assertEquals(wmmTestValues[i][10], result.getDeclination(), degreeEps);
}
}
@Test
public void testInterpolationAtEndOfEpoch() throws OrekitException {
double decimalYear = GeoMagneticField.getDecimalYear(31, 12, 2009);
GeoMagneticField field1 = GeoMagneticFieldFactory.getIGRF(decimalYear);
GeoMagneticField field2 = GeoMagneticFieldFactory.getIGRF(2010.0);
Assert.assertNotEquals(field1.getEpoch(), field2.getEpoch());
GeoMagneticElements e1 = field1.calculateField(0, 0, 0);
Assert.assertEquals(-6.1068, e1.getDeclination(), 1.0e-4);
GeoMagneticElements e2 = field2.calculateField(0, 0, 0);
Assert.assertEquals(-6.1064, e2.getDeclination(), 1.0e-4);
}
public void runSampleFile(final FieldModel type, final String inputFile, final String outputFile)
throws Exception {
final BufferedReader inReader =
new BufferedReader(new InputStreamReader(getResource(inputFile)));
final BufferedReader outReader =
new BufferedReader(new InputStreamReader(getResource(outputFile)));
// read header line
outReader.readLine();
String line = null;
while ((line = inReader.readLine()) != null) {
if (line.trim().length() == 0) {
break;
}
final StringTokenizer st = new StringTokenizer(line);
final double year = getYear(st.nextToken());
final String heightType = st.nextToken();
final String heightStr = st.nextToken();
final double lat = getLatLon(st.nextToken());
final double lon = getLatLon(st.nextToken());
final GeoMagneticField field = GeoMagneticFieldFactory.getField(type, year);
double height = Double.valueOf(heightStr.substring(1));
if (heightStr.startsWith("M")) {
// convert from m to km
height /= 1000d;
} else if (heightStr.startsWith("F")) {
// convert from feet to km
height *= 3.048e-4;
}
final GeoMagneticElements ge = field.calculateField(lat, lon, height);
final String validateLine = outReader.readLine();
// geocentric altitude is not yet supported, ignore by now
if (!heightType.startsWith("C")) {
validate(ge, validateLine);
}
String geString = ge.toString();
Assert.assertNotNull(geString);
Assert.assertFalse(geString.isEmpty());
}
}
@SuppressWarnings("unused")
private void validate(final GeoMagneticElements ge, final String outputLine) throws Exception {
final StringTokenizer st = new StringTokenizer(outputLine);
final double year = getYear(st.nextToken());
final String coord = st.nextToken();
final String heightStr = st.nextToken();
final String latStr = st.nextToken();
final String lonStr = st.nextToken();
final double dec = getDegree(st.nextToken(), st.nextToken());
final double inc = getDegree(st.nextToken(), st.nextToken());
final double h = Double.valueOf(st.nextToken());
final double x = Double.valueOf(st.nextToken());
final double y = Double.valueOf(st.nextToken());
final double z = Double.valueOf(st.nextToken());
final double f = Double.valueOf(st.nextToken());
final double eps = 1e-1;
Assert.assertEquals(h, ge.getHorizontalIntensity(), eps);
Assert.assertEquals(f, ge.getTotalIntensity(), eps);
Assert.assertEquals(x, ge.getFieldVector().getX(), eps);
Assert.assertEquals(y, ge.getFieldVector().getY(), eps);
Assert.assertEquals(z, ge.getFieldVector().getZ(), eps);
Assert.assertEquals(dec, ge.getDeclination(), eps);
Assert.assertEquals(inc, ge.getInclination(), eps);
}
@Test
public void testWMMWithHeightAboveMSL() throws Exception {
// test results for test values provided as part of the WMM2015 Report
// using height above MSL instead of height above ellipsoid
// the results have been obtained from the NOAA online calculator:
// http://www.ngdc.noaa.gov/geomag-web/#igrfwmm
final double[][] testValues = {
// Date Alt Lat Lon X Y Z H F I D
// km deg deg nT nT nT nT nT deg deg
{2015.0, 100, 80, 0, 6314.2, -471.6, 52269.1, 6331.8, 52651.2, 83.093, -4.271},
{2015.0, 100, 0, 120, 37534.4, 364.3, -10773.1, 37536.2, 39051.6, -16.013, 0.556},
{2015.0, 100, -80, 240, 5613.2, 14791.9, -50379.6, 15821.1, 52805.4, -72.565, 69.219}
};
final Geoid geoid = new Geoid(potential, WGS84);
final double eps = 1e-1;
final double degreeEps = 1e-2;
for (int i = 0; i < testValues.length; i++) {
final AbsoluteDate date = new AbsoluteDate(2015, 1, 1, TimeScalesFactory.getUTC());
final GeoMagneticField model = GeoMagneticFieldFactory.getWMM(testValues[i][0]);
final double undulation =
geoid.getUndulation(
FastMath.toRadians(testValues[i][2]), FastMath.toRadians(testValues[i][3]), date);
final GeoMagneticElements result =
model.calculateField(
testValues[i][2], testValues[i][3], testValues[i][1] + undulation / 1000d);
// X
Assert.assertEquals(testValues[i][4], result.getFieldVector().getX(), eps);
// Y
Assert.assertEquals(testValues[i][5], result.getFieldVector().getY(), eps);
// Z
Assert.assertEquals(testValues[i][6], result.getFieldVector().getZ(), eps);
// H
Assert.assertEquals(testValues[i][7], result.getHorizontalIntensity(), eps);
// F
Assert.assertEquals(testValues[i][8], result.getTotalIntensity(), eps);
// inclination
Assert.assertEquals(testValues[i][9], result.getInclination(), degreeEps);
// declination
Assert.assertEquals(testValues[i][10], result.getDeclination(), degreeEps);
}
}
@Test
public void testLoadOriginalWMMModel() throws Exception {
GeoMagneticModelLoader loader = new GeoMagneticModelLoader();
InputStream input = getResource("WMM2015.COF");
loader.loadData(input, "WMM2015.COF");
Collection<GeoMagneticField> models = loader.getModels();
Assert.assertNotNull(models);
Assert.assertEquals(1, models.size());
GeoMagneticField wmmModel = models.iterator().next();
Assert.assertEquals("WMM-2015", wmmModel.getModelName());
Assert.assertEquals(2015, wmmModel.getEpoch(), 1e-9);
final double eps = 1e-1;
final double degreeEps = 1e-2;
for (int i = 0; i < wmmTestValues.length; i++) {
if (wmmTestValues[i][0] != wmmModel.getEpoch()) {
continue;
}
final GeoMagneticElements result =
wmmModel.calculateField(wmmTestValues[i][2], wmmTestValues[i][3], wmmTestValues[i][1]);
// X
Assert.assertEquals(wmmTestValues[i][4], result.getFieldVector().getX(), eps);
// Y
Assert.assertEquals(wmmTestValues[i][5], result.getFieldVector().getY(), eps);
// Z
Assert.assertEquals(wmmTestValues[i][6], result.getFieldVector().getZ(), eps);
// H
Assert.assertEquals(wmmTestValues[i][7], result.getHorizontalIntensity(), eps);
// F
Assert.assertEquals(wmmTestValues[i][8], result.getTotalIntensity(), eps);
// inclination
Assert.assertEquals(wmmTestValues[i][9], result.getInclination(), degreeEps);
// declination
Assert.assertEquals(wmmTestValues[i][10], result.getDeclination(), degreeEps);
}
}
