算法:
怎样用经纬度计算日出日落的时间
下面是一种随经纬度变化的日出日落时间计算方法,我成功运用在一智能路灯控制器中,希望对需要的朋友有帮助。
已知:日出日落时太阳的位置h=-0.833°,要计算地的地理位置,经度Long,纬度G1at,时区zone,UTo为上次计算的日出日落时间,第一次计算时UTo=180°。
(1)先计算出从格林威治时间公元2000年1月1日到计算日天数days;
(2)计算从格林威治时间公元2000年1月1日到计算日的世纪数t, 则t=(days+UTo/360)/36525;
(3)计算太阳的平黄径 : L=280.460+36000.770×t;
(4)计算太阳的平近点角 :G=357.528+35999.050×t
(5)计算太阳的黄道经度 :λ=L+1.915×sinG+0.020xsin(2G);
(6)计算地球的倾角 ε=23.4393-0.0130×t;
(7)计算太阳的偏差 δ=arcsin(sinε×sinλ);
(8)计算格林威治时间的太阳时间角GHA: GHA=UTo-180-1.915×sinG-0.020×sin(2G) +2.466×sin(2λ)-0.053×sin(4λ)
(9)计算修正值e: e=arcos{[ sinh-sin(Glat)sin(δ)]/cos(Glat)cos(δ)}
(10)计算新的日出日落时间 :UT=UTo-(GHA+Long±e); 其中“+”表示计算日出时间,“-”表示计算日落时间;
(11)比较UTo和UT之差的绝对值,如果大于0.1°即0.007小时,把UT作为新的日出日落时间值,重新从第(2)步开始进行迭代计算,如果UTo和UT之差的绝对值小于0.007小时,则UT即为所求的格林威治日出日落时间;
(12)上面的计算以度为单位,即180°=12小时,因此需要转化为以小时表示的时间,再加上所在的时区数Zone,即要计算地的日出日落时间为 :T=UT/15+Zone
上面的计算日出日落时间方法适用于小于北纬60°和南纬60°之间的区域,如果计算位置为西半球时,经度Long为负数。
Java代码:
public class
private static int[] days_of_month_1={31,28,31,30,31,30,31,31,30,31,30,31};
private static int[] days_of_month_2={31,29,31,30,31,30,31,31,30,31,30,31};
private final static double h= -0.833;//日出日落时太阳的位置
private final static double UTo=180.0;//上次计算的日落日出时间,初始迭代值180.0
//输入日期
//输入经纬度
//判断是否为闰年:若为闰年,返回1;若不是闰年,返回0
public static boolean leap_year(int
if(((year%400==0) || (year%100!=0) && (year%4==0))) return true;
else return false;
}
//求从格林威治时间公元2000年1月1日到计算日天数days
public static int days(int year, int month, int date){
int
for(i=2000;i<year;i++){
if(leap_year(i)) a=a+366;
else
if(leap_year(year)){
for(i=0;i<month-1;i++){
a=a+days_of_month_2[i];
}else
for(i=0;i<month-1;i++){
a=a+days_of_month_1[i];
}
}
a=a+date;
return a;
}
//求格林威治时间公元2000年1月1日到计算日的世纪数t
public static double t_century(int days, double UTo){
return ((double)days+UTo/360)/36525;
}
//求太阳的平黄径
public static double L_sun(double t_century){
return (280.460+36000.770*t_century);
}
//求太阳的平近点角
public static double G_sun(double t_century){
return (357.528+35999.050*t_century);
}
//求黄道经度
public static double ecliptic_longitude(double L_sun,double G_sun){
return (L_sun+1.915*Math.sin(G_sun*Math.PI/180)+0.02*Math.sin(2*G_sun*Math.PI/180));
}
//求地球倾角
public static double earth_tilt(double t_century){
return
}
//求太阳偏差
public static double sun_deviation(double earth_tilt,double ecliptic_longitude){
return (180/Math.PI*Math.asin(Math.sin(Math.PI/180*earth_tilt)*Math.sin(Math.PI/180*ecliptic_longitude)));
}
//求格林威治时间的太阳时间角GHA
public static double GHA(double UTo,double G_sun,double ecliptic_longitude){
return (UTo-180-1.915*Math.sin(G_sun*Math.PI/180)-0.02*Math.sin(2*G_sun*Math.PI/180)+2.466*Math.sin(2*ecliptic_longitude*Math.PI/180)-0.053*Math.sin(4*ecliptic_longitude*Math.PI/180));
}
//求修正值e
public static double e(double h,double glat,double
return 180/Math.PI*Math.acos((Math.sin(h*Math.PI/180)-Math.sin(glat*Math.PI/180)*Math.sin(sun_deviation*Math.PI/180))/(Math.cos(glat*Math.PI/180)*Math.cos(sun_deviation*Math.PI/180)));
}
//求日出时间
public static double UT_rise(double UTo,double GHA,double glong,double
return
}
//求日落时间
public static double UT_set(double UTo,double GHA,double glong,double
return
}
//判断并返回结果(日出)
public static double result_rise(double UT,double UTo,double glong, double glat, int year, int month, int date){
double d;
if(UT>=UTo) d=UT-UTo;
else
if(d>=0.1) {
glong,
e(h,glat,sun_deviation(earth_tilt(t_century(days(year,month,date),UTo)),
}
return UT;
}
//判断并返回结果(日落)
public static double result_set(double UT,double UTo,double glong,double glat, int year, int month, int date){
double d;
if(UT>=UTo) d=UT-UTo;
else
if(d>=0.1){
UTo=UT;
e(h,glat,sun_deviation(earth_tilt(t_century(days(year,month,date),UTo)),
G_sun(t_century(days(year,month,date),UTo))))));
result_set(UT,UTo,glong,glat,year,month,date);
}
return UT;
}
//求时区
public static int Zone(double glong){
if(glong>=0) return (int)((int)(glong/15.0)+1);
else return (int)((int)(glong/15.0)-1);
}
//打印结果
public static void output(double rise, double set, double glong){
if((int)(60*(rise/15+Zone(glong)-(int)(rise/15+Zone(glong))))<10)
System.out.println("The time at which the sunrise is: "+(int)(rise/15+Zone(glong))+":"+(int)(60*(rise/15+Zone(glong)-(int)(rise/15+Zone(glong))))+" .\n");
else System.out.println("The time at which the sunrise is: "+(int)(rise/15+Zone(glong))+":"+(int)(60*(rise/15+Zone(glong)-(int)(rise/15+Zone(glong))))+" .\n");
if((int)(60*(set/15+Zone(glong)-(int)(set/15+Zone(glong))))<10)
System.out.println("The time at which the sunset is: "+(int)(set/15+Zone(glong))+": "+(int)(60*(set/15+Zone(glong)-(int)(set/15+Zone(glong))))+" .\n");
else System.out.println("The time at which the sunset is: "+(int)(set/15+Zone(glong))+":"+(int)(60*(set/15+Zone(glong)-(int)(set/15+Zone(glong))))+" .\n");
}
public static
double
int
year=sunTime.year;
month=sunTime.month;
date=sunTime.monthDay;
glong=geoPoint.getLongitude();
glat=geoPoint.getLatitude();
sunrise=result_rise(UT_rise(UTo,
UTo,G_sun(t_century(days(year,month,date),UTo)),
UTo)),
G_sun(t_century(days(year,month,date),UTo)))),
e(h,glat,sun_deviation(earth_tilt(t_century(days(year,month,date),UTo)),
ecliptic_longitude(L_sun(t_century(days(year,month,date),UTo)),
G_sun(t_century(days(year,month,date),UTo)))))),UTo,glong,glat,year,month,date);
//System.out.println("Sunrise is: "+(int)(sunrise/15+Zone(glong))+":"+(int)(60*(sunrise/15+Zone(glong)-(int)(sunrise/15+Zone(glong))))+" .\n");
Log.d("Sunrise", "Sunrise is: "+(int)(sunrise/15+8)+":"+(int)(60*(sunrise/15+8-(int)(sunrise/15+8)))+" .\n");
//return "Sunrise is: "+(int)(sunrise/15+Zone(glong))+":"+(int)(60*(sunrise/15+Zone(glong)-(int)(sunrise/15+Zone(glong))))+" .\n";
return "Sunrise is: "+(int)(sunrise/15+8)+":"+(int)(60*(sunrise/15+8-(int)(sunrise/15+8)))+" .\n";
}
public static
double
int
year=sunTime.year;
month=sunTime.month;
date=sunTime.monthDay;
glong=geoPoint.getLongitude();
glat=geoPoint.getLatitude();
sunset=result_set(UT_set(UTo,
UTo,G_sun(t_century(days(year,month,date),UTo)),
ecliptic_longitude(L_sun(t_century(days(year,month,date),UTo)),
G_sun(t_century(days(year,month,date),UTo)))),
glong,
h,glat,sun_deviation(earth_tilt(t_century(days(year,month,date),UTo)),
ecliptic_longitude(L_sun(t_century(days(year,month,date),UTo)),
G_sun(t_century(days(year,month,date),UTo)))))),UTo,glong,glat,year,month,date);
//System.out.println("The time at which the sunset is: "+(int)(sunset/15+Zone(glong))+":"+(int)(60*(sunset/15+Zone(glong)-(int)(sunset/15+Zone(glong))))+" .\n");
Log.d("Sunset", "Sunset is: "+(int)(sunset/15+8)+":"+(int)(60*(sunset/15+8-(int)(sunset/15+8)))+" .\n");
//return "Sunset is: "+(int)(sunset/15+Zone(glong))+":"+(int)(60*(sunset/15+Zone(glong)-(int)(sunset/15+Zone(glong))))+" .\n";
return "Sunset is: "+(int)(sunset/15+8)+":"+(int)(60*(sunset/15+8-(int)(sunset/15+8)))+" .\n";
}
}
//SunRiseSet.getSunRise(
GeoPoint geoPoint,Time sunTime
),
SunRiseSet.getSunSet(
GeoPoint geoPoint,Time sunTime
)
算出的是北京时间下各地区日出日落时间表,计算当地时间的话,把时区8改为Zone(glong)即可。GeoPoint类是地理位置坐标点类,构造器输入是经纬度。