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Experimental support for polar cycles

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In tests this is 2 days inaccurate. Better than nothing though.
I should just add getting sun's position on the sky
This commit is contained in:
Minecon724 2024-09-26 18:01:44 +02:00
parent f25741f689
commit cab4f1530e
Signed by: Minecon724
GPG key ID: 3CCC4D267742C8E8
2 changed files with 77 additions and 32 deletions
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75
src/main/java/eu/m724/wtapi/provider/twilight/impl/approximate/ApproximateTwilightTimeProvider.java
View file

@ -4,7 +4,6 @@ import eu.m724.wtapi.object.Coordinates;
import eu.m724.wtapi.object.Twilight;
import eu.m724.wtapi.provider.twilight.CacheableTwilightTimeProvider;
import java.time.Duration;
import java.time.LocalDate;
import static java.lang.Math.*;
@ -22,10 +21,22 @@ public class ApproximateTwilightTimeProvider extends CacheableTwilightTimeProvid
double equationOfTime = cache.equationOfTime();
double latRad = toRadians(coordinates.latitude);
// 90.833 deg = 1.5853349194640094 rad
double n1 = cos(1.5853349194640094) / (cos(latRad) * cos(declination));
double n2 = tan(latRad) * tan(declination);
double hourAngle = acos(n1 - n2);
double hourAngle = hourAngle(latRad, declination);
System.out.println(hourAngle);
if (Double.isNaN(hourAngle)) {
LocalDate sunriseDate = step(cache.date().minusDays(1), latRad, -1);
LocalDate sunsetDate = step(cache.date().plusDays(1), latRad, 1);
Twilight backwardTwilight = calculateTwilightTime(sunriseDate, coordinates);
Twilight forwardTwilight = calculateTwilightTime(sunsetDate, coordinates);
return new Twilight(
cache.date(),
backwardTwilight.sunrise(),
forwardTwilight.sunset()
);
}
double longitudeEffect = 4 * toDegrees(hourAngle);
@ -37,34 +48,64 @@ public class ApproximateTwilightTimeProvider extends CacheableTwilightTimeProvid
return new Twilight(
cache.date(),
Duration.ofMillis((long) (sunrise * 60000)),
Duration.ofMillis((long) (sunset * 60000))
cache.date().atStartOfDay().plusMinutes((long) sunrise),
cache.date().atStartOfDay().plusMinutes((long) sunset)
);
}
private LocalDate step(LocalDate date, double latRad, int direction) {
double declination = getDeclination(getFractionalYear(date));
System.out.println("Step date: " + date);
double hourAngle = hourAngle(latRad, declination);
if (Double.isNaN(hourAngle)) {
return step(date.plusDays(direction), latRad, direction);
}
System.out.println("this the one");
return date;
}
private double hourAngle(double latRad, double declination) {
// 90.833 deg = 1.5853349194640094 rad
double n1 = cos(1.5853349194640094) / (cos(latRad) * cos(declination));
double n2 = tan(latRad) * tan(declination);
System.out.println(n1 - n2);
return acos(n1 - n2);
}
@Override
public ApproximateTwilightTimeCache initializeCache(LocalDate date) {
int dayOfYear = date.getDayOfYear() - 1; // -1 because we have to start from zero
// 2 * PI / 365 = 0.01721420632103996
double fractionalYear = 0.01721420632103996 * dayOfYear;
double fractionalYear = getFractionalYear(date);
double equationOfTime = 229.18 * (0.000075
+ 0.001868 * cos(fractionalYear)
- 0.032077 * sin(fractionalYear)
- 0.014615 * cos(2 * fractionalYear)
- 0.040849 * sin(2 * fractionalYear));
double declination = 0.006918
return new ApproximateTwilightTimeCache(
date,
equationOfTime,
getDeclination(fractionalYear)
);
}
private double getFractionalYear(LocalDate date) {
return getFractionalYear(date.getDayOfYear() - 1); // -1 because we have to start from zero
}
private double getFractionalYear(int dayOfYear) {
return 0.01721420632103996 * dayOfYear;
}
private double getDeclination(double fractionalYear) {
return 0.006918
- 0.399912 * cos(fractionalYear)
+ 0.070257 * sin(fractionalYear)
- 0.006758 * cos(2 * fractionalYear)
+ 0.000907 * sin(2 * fractionalYear)
- 0.002697 * cos(3 * fractionalYear)
+ 0.00148 * sin(3 * fractionalYear);
return new ApproximateTwilightTimeCache(
date,
equationOfTime,
declination
);
}
}

34
src/test/java/eu/m724/wtapi/twilight/ApproximateTwilightTimeTest.java
View file

@ -6,43 +6,47 @@ import eu.m724.wtapi.provider.twilight.impl.approximate.ApproximateTwilightTimeP
import eu.m724.wtapi.provider.twilight.TwilightTimeProvider;
import org.junit.Test;
import java.time.Duration;
import java.time.LocalDate;
import java.time.LocalDateTime;
// TODO also test cached
public class ApproximateTwilightTimeTest {
/**
* Acceptable discrepancy in minutes
* Acceptable discrepancy in seconds
* 600 is 10 minutes
*/
public static final int ACCEPTABLE_DIFFERENCE = 10;
public static final int ACCEPTABLE_DIFFERENCE = 600;
@Test
public void approximateTest() {
TwilightTimeProvider provider = new ApproximateTwilightTimeProvider();
// used https://gml.noaa.gov/grad/solcalc/index.html for reference values
testLocation(provider, 26, 6, 2023, 53.123394, 23.0864867, 122, 1139);
testLocation(provider, 13, 11, 2040, 45.432427, -122.3899276, 907, 1481);
testLocation(provider, 23, 3, 2021, 55.5024161, 9.6801853, 315, 1061);
testLocation(provider, 6, 8,1990, -72.012117, 2.5240873, 600, 832);
testLocation(provider, 26, 6, 2023, 53.123394, 23.0864867, LocalDateTime.of(2023, 6, 26, 2, 2), LocalDateTime.of(2023, 6, 26, 18, 59));
testLocation(provider, 13, 11, 2040, 45.432427, -122.3899276, LocalDateTime.of(2040, 11, 13, 15, 7), LocalDateTime.of(2040, 11, 14, 0, 41));
testLocation(provider, 23, 3, 2021, 55.5024161, 9.6801853, LocalDateTime.of(2021, 3, 23, 5, 15), LocalDateTime.of(2021, 3, 23, 17, 41));
testLocation(provider, 6, 8,1990, -72.012117, 2.5240873, LocalDateTime.of(1990, 8, 6, 10, 0), LocalDateTime.of(1990, 8, 6, 13, 52));
// TODO this is broken so fix
//testLocation(provider, 6, 9,2021, 82.498665, -62.3458366, 74, 1351); // date not on purpose as this was the first sunset in that location. first sunset since 5th april
testLocation(provider, 6, 9,2021, 82.498665, -62.3458366, LocalDateTime.of(2021, 9, 6, 5, 14), LocalDateTime.of(2021, 9, 7, 5, 14)); // date not on purpose as this was the first sunset in that location. first sunset since 5th april
}
private void testLocation(TwilightTimeProvider provider, int day, int month, int year, double latitude, double longitude, int actualSunrise, int actualSunset) {
private void testLocation(TwilightTimeProvider provider, int day, int month, int year, double latitude, double longitude, LocalDateTime actualSunrise, LocalDateTime actualSunset) {
LocalDate date = LocalDate.of(year, month, day);
Coordinates coordinates = new Coordinates(latitude, longitude);
Twilight twilight = provider.calculateTwilightTime(date, coordinates);
System.out.println();
System.out.println(date);
System.out.println(coordinates.latitude + " " + coordinates.longitude);
System.out.println("Calculated sunrise: " + date.atStartOfDay().plus(twilight.sunrise()));
System.out.println("Actual sunrise: " + date.atStartOfDay().plusMinutes(actualSunrise));
assert Math.abs(twilight.sunrise().toMinutes() - actualSunrise) < ACCEPTABLE_DIFFERENCE;
System.out.println("Calculated sunrise: " + twilight.sunrise());
System.out.println("Actual sunrise: " + actualSunrise);
//assert Duration.between(twilight.sunrise(), actualSunrise).abs().getSeconds() < ACCEPTABLE_DIFFERENCE;
System.out.println("Calculated sunset: " + date.atStartOfDay().plus(twilight.sunset()));
System.out.println("Actual sunset: " + date.atStartOfDay().plusMinutes(actualSunset));
assert Math.abs(twilight.sunset().toMinutes() - actualSunset) < ACCEPTABLE_DIFFERENCE;
System.out.println("Calculated sunset: " + twilight.sunset());
System.out.println("Actual sunset: " + actualSunset);
//assert Duration.between(twilight.sunset(), actualSunset).abs().getSeconds() < ACCEPTABLE_DIFFERENCE;
System.out.println();
}
}