783 lines
25 KiB
Java
783 lines
25 KiB
Java
package net.osmand.util;
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/******************************************************************************
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*
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* SunriseSunset.java
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*
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*******************************************************************************
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*
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* Java Class: SunriseSunset
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*
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* This Java class is part of a collection of classes developed for the
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* reading and processing of oceanographic and meterological data collected
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* since 1970 by environmental buoys and stations. This dataset is
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* maintained by the National Oceanographic Data Center and is publicly
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* available. These Java classes were written for the US Environmental
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* Protection Agency's National Exposure Research Laboratory under Contract
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* No. GS-10F-0073K with Neptune and Company of Los Alamos, New Mexico.
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*
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* Purpose:
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*
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* This Java class performs calculations to determine the time of
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* sunrise and sunset given lat, long, and date.
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*
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* Inputs:
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*
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* Latitude, longitude, date/time, and time zone.
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*
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* Outputs:
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*
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* Local time of sunrise and sunset as calculated by the
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* program.
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* If no sunrise or no sunset occurs, or if the sun is up all day
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* or down all day, appropriate boolean values are set.
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* A boolean is provided to identify if the time provided is during the day.
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*
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* The above values are accessed by the following methods:
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*
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* Date getSunrise() returns date/time of sunrise
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* Date getSunset() returns date/time of sunset
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* boolean isSunrise() returns true if there was a sunrise, else false
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* boolean isSunset() returns true if there was a sunset, else false
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* boolean isSunUp() returns true if sun is up all day, else false
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* boolean isSunDown() returns true if sun is down all day, else false
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* boolean isDaytime() returns true if sun is up at the time
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* specified, else false
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*
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* Required classes from the Java library:
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*
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* java.util.Date
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* java.text.SimpleDateFormat
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* java.text.ParseException;
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* java.math.BigDecimal;
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*
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* Package of which this class is a member:
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*
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* default
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*
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* Known limitations:
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*
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* It is assumed that the data provided are within value ranges
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* (i.e. latitude between -90 and +90, longitude between 0 and 360,
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* a valid date, and time zone between -14 and +14.
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*
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* Compatibility:
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*
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* Java 1.1.8
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*
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* References:
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*
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* The mathematical algorithms used in this program are patterned
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* after those debveloped by Roger Sinnott in his BASIC program,
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* SUNUP.BAS, published in Sky & Telescope magazine:
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* Sinnott, Roger W. "Sunrise and Sunset: A Challenge"
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* Sky & Telescope, August, 1994 p.84-85
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*
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* The following is a cross-index of variables used in SUNUP.BAS.
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* A single definition from multiple reuse of variable names in
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* SUNUP.BAS was clarified with various definitions in this program.
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*
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* SUNUP.BAS this class
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*
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* A dfA
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* A(2) dfAA1, dfAA2
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* A0 dfA0
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* A2 dfA2
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* A5 dfA5
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* AZ Not used
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* C dfCosLat
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* C0 dfC0
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* D iDay
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* D(2) dfDD1, dfDD2
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* D0 dfD0
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* D1 dfD1
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* D2 dfD2
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* D5 dfD5
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* D7 Not used
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* DA dfDA
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* DD dfDD
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* G bGregorian, dfGG
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* H dfTimeZone
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* H0 dfH0
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* H1 dfH1
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* H2 dfH2
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* H3 dfHourRise, dfHourSet
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* H7 Not used
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* J dfJ
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* J3 dfJ3
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* K1 dfK1
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* L dfLL
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* L0 dfL0
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* L2 dfL2
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* L5 dfLon
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* M iMonth
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* M3 dfMinRise, dfMinSet
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* N7 Not used
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* P dfP
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* S iSign, dfSinLat, dfSS
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* T dfT
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* T0 dfT0
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* T3 not used
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* TT dfTT
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* U dfUU
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* V dfVV
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* V0 dfV0
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* V1 dfV1
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* V2 dfV2
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* W dfWW
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* Y iYear
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* Z dfZenith
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* Z0 dfTimeZone
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*
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*
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* Author/Company:
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*
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* JDT: John Tauxe, Neptune and Company
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* JMG: Jo Marie Green
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*
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* Change log:
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*
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* date ver by description of change
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* _________ _____ ___ ______________________________________________
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* 5 Jan 01 0.006 JDT Excised from ssapp.java v. 0.005.
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* 11 Jan 01 0.007 JDT Minor modifications to comments based on
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* material from Sinnott, 1994.
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* 7 Feb 01 0.008 JDT Fixed backwards time zone. The standard is that
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* local time zone is specified in hours EAST of
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* Greenwich, so that EST would be -5, for example.
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* For some reason, SUNUP.BAS does this backwards
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* (probably an americocentric perspective) and
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* SunriseSunset adopted that convention. Oops.
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* So the sign in the math is changed.
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* 7 Feb 01 0.009 JDT Well, that threw off the azimuth calculation...
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* Removed the azimuth calculations.
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* 14 Feb 01 0.010 JDT Added ability to accept a time (HH:mm) in
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* dateInput, and decide if that time is daytime
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* or nighttime.
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* 27 Feb 01 0.011 JDT Added accessor methods in place of having public
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* variables to get results.
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* 28 Feb 01 0.012 JDT Cleaned up list of imported classes.
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* 28 Mar 01 1.10 JDT Final version accompanying deliverable 1b.
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* 4 Apr 01 1.11 JDT Moved logic supporting .isDaytime into method.
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* Moved calculations out of constructor.
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* 01 May 01 1.12 JMG Added 'GMT' designation and testing lines.
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* 16 May 01 1.13 JDT Added setLenient( false ) and setTimeZone( tz )
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* to dfmtDay, dfmtMonth, and dfmtYear in
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* doCalculations.
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* 27 Jun 01 1.14 JDT Removed reliance on StationConstants (GMT).
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* 13 Aug 01 1.20 JDT Final version accompanying deliverable 1c.
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* 6 Sep 01 1.21 JDT Thorough code and comment review.
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* 21 Sep 01 1.30 JDT Final version accompanying deliverable 2.
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* 17 Dec 01 1.40 JDT Version accompanying final deliverable.
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*
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*----------------------------------------------------------------------------*/
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import java.util.Calendar;
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import java.util.Date;
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import java.util.TimeZone;
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/******************************************************************************
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* class: SunriseSunset class
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*******************************************************************************
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*
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* This Java class performs calculations to determine the time of
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* sunrise and sunset given lat, long, and date.
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*
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* It is assumed that the data provided are within value ranges
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* (i.e. latitude between -90 and +90, longitude between 0 and 360,
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* a valid date, and time zone between -14 and +14.
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*
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*----------------------------------------------------------------------------*/
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public class SunriseSunset
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{
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// Declare and initialize variables
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private double dfLat; // latitude from user
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private double dfLon; // latitude from user
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private Date dateInput; // date/time from user
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private double dfTimeZone; // time zone from user
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private Date dateSunrise; // date and time of sunrise
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private Date dateSunset; // date and time of sunset
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private boolean bSunriseToday = false; // flag for sunrise on this date
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private boolean bSunsetToday = false; // flag for sunset on this date
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private boolean bSunUpAllDay = false; // flag for sun up all day
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private boolean bSunDownAllDay = false; // flag for sun down all day
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private boolean bDaytime = false; // flag for daytime, given
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// hour and min in dateInput
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private boolean bSunrise = false; // sunrise during hour checked
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private boolean bSunset = false; // sunset during hour checked
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private boolean bGregorian = false; // flag for Gregorian calendar
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private int iJulian; // Julian day
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private int iYear; // year of date of interest
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private int iMonth; // month of date of interest
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private int iDay; // day of date of interest
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private int iCount; // a simple counter
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private int iSign; // SUNUP.BAS: S
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private int dfHourRise, dfHourSet; // hour of event: SUNUP.BAS H3
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private int dfMinRise, dfMinSet; // minute of event: SUNUP.BAS M3
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private double dfSinLat, dfCosLat; // sin and cos of latitude
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private double dfZenith; // SUNUP.BAS Z: Zenith
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// Many variables in SUNUP.BAS have undocumented meanings,
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// and so are translated rather directly to avoid confusion:
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private double dfAA1 = 0, dfAA2 = 0; // SUNUP.BAS A(2)
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private double dfDD1 = 0, dfDD2 = 0; // SUNUP.BAS D(2)
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private double dfC0; // SUNUP.BAS C0
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private double dfK1; // SUNUP.BAS K1
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private double dfP; // SUNUP.BAS P
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private double dfJ; // SUNUP.BAS J
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private double dfJ3; // SUNUP.BAS J3
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private double dfA; // SUNUP.BAS A
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private double dfA0, dfA2, dfA5; // SUNUP.BAS A0, A2, A5
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private double dfD0, dfD1, dfD2, dfD5; // SUNUP.BAS D0, D1, D2, D5
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private double dfDA, dfDD; // SUNUP.BAS DA, DD
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private double dfH0, dfH1, dfH2; // SUNUP.BAS H0, H1, H2
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private double dfL0, dfL2; // SUNUP.BAS L0, L2
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private double dfT, dfT0, dfTT; // SUNUP.BAS T, T0, TT
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private double dfV0, dfV1, dfV2; // SUNUP.BAS V0, V1, V2
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/******************************************************************************
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* method: SunriseSunset
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*******************************************************************************
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*
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* Constructor for SunriseSunset class.
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*
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*----------------------------------------------------------------------------*/
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public SunriseSunset(
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double dfLatIn, // latitude
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double dfLonIn, // longitude
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Date dateInputIn, // date
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TimeZone tzIn // time zone
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)
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{
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// Calculate internal representation of timezone offset as fraction of hours from GMT
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// Our calculations consider offsets to the West as positive, so we must invert
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// the signal of the values provided by the standard library
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double dfTimeZoneIn = 1.0 * tzIn.getOffset(dateInputIn.getTime()) / 3600000;
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// Copy values supplied as agruments to local variables.
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dfLat = dfLatIn;
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dfLon = dfLonIn;
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dateInput = dateInputIn;
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dfTimeZone = dfTimeZoneIn;
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// Call the method to do the calculations.
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doCalculations();
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} // end of class constructor
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/******************************************************************************
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* method: doCalculations
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*******************************************************************************
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*
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* Method for performing the calculations done in SUNUP.BAS.
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*
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*----------------------------------------------------------------------------*/
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private void doCalculations()
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{
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// Break out day, month, and year from date provided using local time zone.
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// (This is necessary for the math algorithms.)
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Calendar cin = Calendar.getInstance();
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cin.setTime(dateInput);
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iYear = cin.get(Calendar.YEAR);
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iMonth = cin.get(Calendar.MONTH) + 1;
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iDay = cin.get(Calendar.DAY_OF_MONTH);
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// Convert time zone hours to decimal days (SUNUP.BAS line 50)
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dfTimeZone = dfTimeZone / 24.0;
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// NOTE: (7 Feb 2001) Here is a non-standard part of SUNUP.BAS:
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// It (and this algorithm) assumes that the time zone is
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// positive west, instead of the standard negative west.
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// Classes calling SunriseSunset will be assuming that
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// times zones are specified in negative west, so here the
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// sign is changed so that the SUNUP algorithm works:
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dfTimeZone = -dfTimeZone;
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// Convert longitude to fraction (SUNUP.BAS line 50)
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dfLon = dfLon / 360.0;
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// Convert calendar date to Julian date:
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// Check to see if it's later than 1583: Gregorian calendar
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// When declared, bGregorian is initialized to false.
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// ** Consider making a separate class of this function. **
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if( iYear >= 1583 ) bGregorian = true;
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// SUNUP.BAS 1210
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dfJ = -Math.floor( 7.0 // SUNUP used INT, not floor
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* ( Math.floor(
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( iMonth + 9.0 )
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/ 12.0
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) + iYear
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) / 4.0
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)
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// add SUNUP.BAS 1240 and 1250 for G = 0
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+ Math.floor( iMonth * 275.0 / 9.0 )
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+ iDay
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+ 1721027.0
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+ iYear * 367.0;
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if ( bGregorian )
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{
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// SUNUP.BAS 1230
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if ( ( iMonth - 9.0 ) < 0.0 ) iSign = -1;
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else iSign = 1;
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dfA = Math.abs( iMonth - 9.0 );
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// SUNUP.BAS 1240 and 1250
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dfJ3 = -Math.floor(
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(
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Math.floor(
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Math.floor( iYear
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+ (double)iSign
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* Math.floor( dfA / 7.0 )
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)
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/ 100.0
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) + 1.0
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) * 0.75
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);
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// correct dfJ as in SUNUP.BAS 1240 and 1250 for G = 1
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dfJ = dfJ + dfJ3 + 2.0;
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}
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// SUNUP.BAS 1290
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iJulian = (int)dfJ - 1;
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// SUNUP.BAS 60 and 70 (see also line 1290)
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dfT = (double)iJulian - 2451545.0 + 0.5;
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dfTT = dfT / 36525.0 + 1.0; // centuries since 1900
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// Calculate local sidereal time at 0h in zone time
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// SUNUP.BAS 410 through 460
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dfT0 = ( dfT * 8640184.813 / 36525.0
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+ 24110.5
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+ dfTimeZone * 86636.6
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+ dfLon * 86400.0
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)
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/ 86400.0;
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dfT0 = dfT0 - Math.floor( dfT0 ); // NOTE: SUNUP.BAS uses INT()
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dfT0 = dfT0 * 2.0 * Math.PI;
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// SUNUP.BAS 90
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dfT = dfT + dfTimeZone;
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// SUNUP.BAS 110: Get Sun's position
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for( iCount=0; iCount<=1; iCount++ ) // Loop thru only twice
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{
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// Calculate Sun's right ascension and declination
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// at the start and end of each day.
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// SUNUP.BAS 910 - 1160: Fundamental arguments
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// from van Flandern and Pulkkinen, 1979
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// declare local temporary doubles for calculations
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double dfGG; // SUNUP.BAS G
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double dfLL; // SUNUP.BAS L
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double dfSS; // SUNUP.BAS S
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double dfUU; // SUNUP.BAS U
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double dfVV; // SUNUP.BAS V
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double dfWW; // SUNUP.BAS W
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dfLL = 0.779072 + 0.00273790931 * dfT;
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dfLL = dfLL - Math.floor( dfLL );
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dfLL = dfLL * 2.0 * Math.PI;
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dfGG = 0.993126 + 0.0027377785 * dfT;
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dfGG = dfGG - Math.floor( dfGG );
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dfGG = dfGG * 2.0 * Math.PI;
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dfVV = 0.39785 * Math.sin( dfLL )
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- 0.01000 * Math.sin( dfLL - dfGG )
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+ 0.00333 * Math.sin( dfLL + dfGG )
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- 0.00021 * Math.sin( dfLL ) * dfTT;
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dfUU = 1
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- 0.03349 * Math.cos( dfGG )
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- 0.00014 * Math.cos( dfLL * 2.0 )
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+ 0.00008 * Math.cos( dfLL );
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dfWW = - 0.00010
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- 0.04129 * Math.sin( dfLL * 2.0 )
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+ 0.03211 * Math.sin( dfGG )
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- 0.00104 * Math.sin( 2.0 * dfLL - dfGG )
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- 0.00035 * Math.sin( 2.0 * dfLL + dfGG )
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- 0.00008 * Math.sin( dfGG ) * dfTT;
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// Compute Sun's RA and Dec; SUNUP.BAS 1120 - 1140
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dfSS = dfWW / Math.sqrt( dfUU - dfVV * dfVV );
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dfA5 = dfLL
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+ Math.atan( dfSS / Math.sqrt( 1.0 - dfSS * dfSS ));
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dfSS = dfVV / Math.sqrt( dfUU );
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dfD5 = Math.atan( dfSS / Math.sqrt( 1 - dfSS * dfSS ));
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// Set values and increment t
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if ( iCount == 0 ) // SUNUP.BAS 125
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{
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dfAA1 = dfA5;
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dfDD1 = dfD5;
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}
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else // SUNUP.BAS 145
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{
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dfAA2 = dfA5;
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dfDD2 = dfD5;
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}
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dfT = dfT + 1.0; // SUNUP.BAS 130
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} // end of Get Sun's Position for loop
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if ( dfAA2 < dfAA1 ) dfAA2 = dfAA2 + 2.0 * Math.PI;
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// SUNUP.BAS 150
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dfZenith = Math.PI * 90.833 / 180.0; // SUNUP.BAS 160
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dfSinLat = Math.sin( dfLat * Math.PI / 180.0 ); // SUNUP.BAS 170
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dfCosLat = Math.cos( dfLat * Math.PI / 180.0 ); // SUNUP.BAS 170
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dfA0 = dfAA1; // SUNUP.BAS 190
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dfD0 = dfDD1; // SUNUP.BAS 190
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dfDA = dfAA2 - dfAA1; // SUNUP.BAS 200
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dfDD = dfDD2 - dfDD1; // SUNUP.BAS 200
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dfK1 = 15.0 * 1.0027379 * Math.PI / 180.0; // SUNUP.BAS 330
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// Initialize sunrise and sunset times, and other variables
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// hr and min are set to impossible times to make errors obvious
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dfHourRise = 99;
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dfMinRise = 99;
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dfHourSet = 99;
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dfMinSet = 99;
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dfV0 = 0.0; // initialization implied by absence in SUNUP.BAS
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dfV2 = 0.0; // initialization implied by absence in SUNUP.BAS
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// Test each hour to see if the Sun crosses the horizon
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// and which way it is heading.
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for( iCount=0; iCount<24; iCount++ ) // SUNUP.BAS 210
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{
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double tempA; // SUNUP.BAS A
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double tempB; // SUNUP.BAS B
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double tempD; // SUNUP.BAS D
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double tempE; // SUNUP.BAS E
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dfC0 = (double)iCount;
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dfP = ( dfC0 + 1.0 ) / 24.0; // SUNUP.BAS 220
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dfA2 = dfAA1 + dfP * dfDA; // SUNUP.BAS 230
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dfD2 = dfDD1 + dfP * dfDD; // SUNUP.BAS 230
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dfL0 = dfT0 + dfC0 * dfK1; // SUNUP.BAS 500
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dfL2 = dfL0 + dfK1; // SUNUP.BAS 500
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dfH0 = dfL0 - dfA0; // SUNUP.BAS 510
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dfH2 = dfL2 - dfA2; // SUNUP.BAS 510
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// hour angle at half hour
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dfH1 = ( dfH2 + dfH0 ) / 2.0; // SUNUP.BAS 520
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// declination at half hour
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dfD1 = ( dfD2 + dfD0 ) / 2.0; // SUNUP.BAS 530
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// Set value of dfV0 only if this is the first hour,
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// otherwise, it will get set to the last dfV2 (SUNUP.BAS 250)
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if ( iCount == 0 ) // SUNUP.BAS 550
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{
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dfV0 = dfSinLat * Math.sin( dfD0 )
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+ dfCosLat * Math.cos( dfD0 ) * Math.cos( dfH0 )
|
|
- Math.cos( dfZenith ); // SUNUP.BAS 560
|
|
}
|
|
else
|
|
dfV0 = dfV2; // That is, dfV2 from the previous hour.
|
|
|
|
dfV2 = dfSinLat * Math.sin( dfD2 )
|
|
+ dfCosLat * Math.cos( dfD2 ) * Math.cos( dfH2 )
|
|
- Math.cos( dfZenith ); // SUNUP.BAS 570
|
|
|
|
// if dfV0 and dfV2 have the same sign, then proceed to next hr
|
|
if (
|
|
( dfV0 >= 0.0 && dfV2 >= 0.0 ) // both are positive
|
|
|| // or
|
|
( dfV0 < 0.0 && dfV2 < 0.0 ) // both are negative
|
|
)
|
|
{
|
|
// Break iteration and proceed to test next hour
|
|
dfA0 = dfA2; // SUNUP.BAS 250
|
|
dfD0 = dfD2; // SUNUP.BAS 250
|
|
continue; // SUNUP.BAS 610
|
|
}
|
|
|
|
dfV1 = dfSinLat * Math.sin( dfD1 )
|
|
+ dfCosLat * Math.cos( dfD1 ) * Math.cos( dfH1 )
|
|
- Math.cos( dfZenith ); // SUNUP.BAS 590
|
|
|
|
tempA = 2.0 * dfV2 - 4.0 * dfV1 + 2.0 * dfV0;
|
|
// SUNUP.BAS 600
|
|
tempB = 4.0 * dfV1 - 3.0 * dfV0 - dfV2; // SUNUP.BAS 600
|
|
tempD = tempB * tempB - 4.0 * tempA * dfV0; // SUNUP.BAS 610
|
|
|
|
if ( tempD < 0.0 )
|
|
{
|
|
// Break iteration and proceed to test next hour
|
|
dfA0 = dfA2; // SUNUP.BAS 250
|
|
dfD0 = dfD2; // SUNUP.BAS 250
|
|
continue; // SUNUP.BAS 610
|
|
}
|
|
|
|
tempD = Math.sqrt( tempD ); // SUNUP.BAS 620
|
|
|
|
// Determine occurence of sunrise or sunset.
|
|
|
|
// Flags to identify occurrence during this day are
|
|
// bSunriseToday and bSunsetToday, and are initialized false.
|
|
// These are set true only if sunrise or sunset occurs
|
|
// at any point in the hourly loop. Never set to false.
|
|
|
|
// Flags to identify occurrence during this hour:
|
|
bSunrise = false; // reset before test
|
|
bSunset = false; // reset before test
|
|
|
|
if ( dfV0 < 0.0 && dfV2 > 0.0 ) // sunrise occurs this hour
|
|
{
|
|
bSunrise = true; // SUNUP.BAS 640
|
|
bSunriseToday = true; // sunrise occurred today
|
|
}
|
|
|
|
if ( dfV0 > 0.0 && dfV2 < 0.0 ) // sunset occurs this hour
|
|
{
|
|
bSunset = true; // SUNUP.BAS 660
|
|
bSunsetToday = true; // sunset occurred today
|
|
}
|
|
|
|
tempE = ( tempD - tempB ) / ( 2.0 * tempA );
|
|
if ( tempE > 1.0 || tempE < 0.0 ) // SUNUP.BAS 670, 680
|
|
tempE = ( -tempD - tempB ) / ( 2.0 * tempA );
|
|
|
|
// Set values of hour and minute of sunset or sunrise
|
|
// only if sunrise/set occurred this hour.
|
|
if ( bSunrise )
|
|
{
|
|
dfHourRise = (int)( dfC0 + tempE + 1.0/120.0 );
|
|
dfMinRise = (int) (
|
|
( dfC0 + tempE + 1.0/120.0
|
|
- dfHourRise
|
|
)
|
|
* 60.0
|
|
);
|
|
}
|
|
|
|
if ( bSunset )
|
|
{
|
|
dfHourSet = (int) ( dfC0 + tempE + 1.0/120.0 );
|
|
dfMinSet = (int)(
|
|
( dfC0 + tempE + 1.0/120.0
|
|
- dfHourSet
|
|
)
|
|
* 60.0
|
|
);
|
|
}
|
|
|
|
// Change settings of variables for next loop
|
|
dfA0 = dfA2; // SUNUP.BAS 250
|
|
dfD0 = dfD2; // SUNUP.BAS 250
|
|
|
|
} // end of loop testing each hour for an event
|
|
|
|
// After having checked all hours, set flags if no rise or set
|
|
// bSunUpAllDay and bSundownAllDay are initialized as false
|
|
if ( !bSunriseToday && !bSunsetToday )
|
|
{
|
|
if ( dfV2 < 0.0 )
|
|
bSunDownAllDay = true;
|
|
else
|
|
bSunUpAllDay = true;
|
|
}
|
|
|
|
// Load dateSunrise with data
|
|
|
|
if( bSunriseToday )
|
|
{
|
|
Calendar c = Calendar.getInstance();
|
|
c.set(Calendar.YEAR, iYear);
|
|
c.set(Calendar.MONTH, iMonth-1);
|
|
c.set(Calendar.DAY_OF_MONTH, iDay);
|
|
c.set(Calendar.HOUR_OF_DAY, dfHourRise);
|
|
c.set(Calendar.MINUTE, dfMinRise);
|
|
dateSunrise = c.getTime();
|
|
}
|
|
|
|
// Load dateSunset with data
|
|
if( bSunsetToday )
|
|
{
|
|
Calendar c = Calendar.getInstance();
|
|
c.set(Calendar.YEAR, iYear);
|
|
c.set(Calendar.MONTH, iMonth-1);
|
|
c.set(Calendar.DAY_OF_MONTH, iDay);
|
|
c.set(Calendar.HOUR_OF_DAY, dfHourSet);
|
|
c.set(Calendar.MINUTE, dfMinSet);
|
|
dateSunset = c.getTime();
|
|
}
|
|
}
|
|
|
|
|
|
/******************************************************************************
|
|
* method: getSunrise()
|
|
*******************************************************************************
|
|
*
|
|
* Gets the date and time of sunrise. If there is no sunrise, returns null.
|
|
*
|
|
* Member of SunriseSunset class
|
|
*
|
|
* -------------------------------------------------------------------------- */
|
|
public Date getSunrise()
|
|
{
|
|
if ( bSunriseToday )
|
|
return( dateSunrise );
|
|
else
|
|
return( null );
|
|
}
|
|
|
|
|
|
/******************************************************************************
|
|
* method: getSunset()
|
|
*******************************************************************************
|
|
*
|
|
* Gets the date and time of sunset. If there is no sunset, returns null.
|
|
*
|
|
* Member of SunriseSunset class
|
|
*
|
|
* -------------------------------------------------------------------------- */
|
|
public Date getSunset()
|
|
{
|
|
if ( bSunsetToday )
|
|
return( dateSunset );
|
|
else
|
|
return( null );
|
|
}
|
|
|
|
|
|
/******************************************************************************
|
|
* method: isSunrise()
|
|
*******************************************************************************
|
|
*
|
|
* Returns a boolean identifying if there was a sunrise.
|
|
*
|
|
* Member of SunriseSunset class
|
|
*
|
|
* -------------------------------------------------------------------------- */
|
|
public boolean isSunrise()
|
|
{
|
|
return( bSunriseToday );
|
|
}
|
|
|
|
|
|
/******************************************************************************
|
|
* method: isSunset()
|
|
*******************************************************************************
|
|
*
|
|
* Returns a boolean identifying if there was a sunset.
|
|
*
|
|
* Member of SunriseSunset class
|
|
*
|
|
* -------------------------------------------------------------------------- */
|
|
public boolean isSunset()
|
|
{
|
|
return( bSunsetToday );
|
|
}
|
|
|
|
|
|
/******************************************************************************
|
|
* method: isSunUp()
|
|
*******************************************************************************
|
|
*
|
|
* Returns a boolean identifying if the sun is up all day.
|
|
*
|
|
* Member of SunriseSunset class
|
|
*
|
|
* -------------------------------------------------------------------------- */
|
|
public boolean isSunUp()
|
|
{
|
|
return( bSunUpAllDay );
|
|
}
|
|
|
|
|
|
/******************************************************************************
|
|
* method: isSunDown()
|
|
*******************************************************************************
|
|
*
|
|
* Returns a boolean identifying if the sun is down all day.
|
|
*
|
|
* Member of SunriseSunset class
|
|
*
|
|
* -------------------------------------------------------------------------- */
|
|
public boolean isSunDown()
|
|
{
|
|
return( bSunDownAllDay );
|
|
}
|
|
|
|
|
|
/******************************************************************************
|
|
* method: isDaytime()
|
|
*******************************************************************************
|
|
*
|
|
* Returns a boolean identifying if it is daytime at the hour contained in
|
|
* the Date object passed to SunriseSunset on construction.
|
|
*
|
|
* Member of SunriseSunset class
|
|
*
|
|
* -------------------------------------------------------------------------- */
|
|
public boolean isDaytime()
|
|
{
|
|
// Determine if it is daytime (at sunrise or later)
|
|
// or nighttime (at sunset or later) at the location of interest
|
|
// but expressed in the time zone requested.
|
|
if ( bSunriseToday && bSunsetToday ) // sunrise and sunset
|
|
{
|
|
if ( dateSunrise.before( dateSunset ) ) // sunrise < sunset
|
|
{
|
|
if (
|
|
(
|
|
dateInput.after( dateSunrise )
|
|
||
|
|
dateInput.equals( dateSunrise )
|
|
)
|
|
&&
|
|
dateInput.before( dateSunset )
|
|
)
|
|
bDaytime = true;
|
|
else
|
|
bDaytime = false;
|
|
}
|
|
else // sunrise comes after sunset (in opposite time zones)
|
|
{
|
|
if (
|
|
(
|
|
dateInput.after( dateSunrise )
|
|
||
|
|
dateInput.equals( dateSunrise )
|
|
)
|
|
|| // use OR rather than AND
|
|
dateInput.before( dateSunset )
|
|
)
|
|
bDaytime = true;
|
|
else
|
|
bDaytime = false;
|
|
}
|
|
}
|
|
else if ( bSunUpAllDay ) // sun is up all day
|
|
bDaytime = true;
|
|
else if ( bSunDownAllDay ) // sun is down all day
|
|
bDaytime = false;
|
|
else if ( bSunriseToday ) // sunrise but no sunset
|
|
{
|
|
if ( dateInput.before( dateSunrise ) )
|
|
bDaytime = false;
|
|
else
|
|
bDaytime = true;
|
|
}
|
|
else if ( bSunsetToday ) // sunset but no sunrise
|
|
{
|
|
if ( dateInput.before( dateSunset ) )
|
|
bDaytime = true;
|
|
else
|
|
bDaytime = false;
|
|
}
|
|
else bDaytime = false; // this should never execute
|
|
|
|
return( bDaytime );
|
|
}
|
|
} // end of class
|
|
|
|
/*-----------------------------------------------------------------------------
|
|
* end of class
|
|
*----------------------------------------------------------------------------*/
|
|
|