JavaScript - 计算正午太阳高度

Posted 2020-10-09

 1 /*
 2  * 正午太阳高度计算代码
 3  *
 4  * NurtaySolarAltitude(所求纬度, 南北半球(N或S), 月, 日)
 5  *
 6  */
 7 function NurtaySolarAltitude(a, b, c, d) {
 8     function e(a, b, c, d, e, f) {
 9         var g = new Date(a, b - 1, c),
10             h = new Date(d, e - 1, f),
11             i = (g - h) / 864e5;
12         i = Math.abs(i);
13         return i;
14     }
15     function f(a) {
16         var b, c, d;
17         a = Math.abs(a);
18         b = Math.floor(a);
19         c = Math.floor(60 * (a - b));
20         d = Math.round(3600 * (a - b) % 60);
21         return b + "°" + c + "‘" + d + ‘"‘;
22     }
23     function g(a) {
24         return -a;
25     }
26     function h(a, b, c) {
27         var d;
28         if ("N" == c) d = 90 - Math.abs(a - b);
29         if ("S" == c) d = 90 - Math.abs(a + b);
30         return d;
31     }
32     var i;
33     a = Math.abs(a);
34     c = Math.abs(c);
35     d = Math.abs(d);
36     if (3 == c && 21 == d || 9 == c && 23 == d) {
37         i = 0
38     };
39     if (3 == c && d > 21 || c > 3 && c < 6 || 6 == c && d < 22) {
40         i = .25188917 * e(0, c, d, 0, "3", "21")
41     };
42     if (6 == c && 22 == d) {
43         i = 23.43333333
44     };
45     if (6 == c && d > 22 || c > 6 && c < 9 || 9 == c && d < 23) {
46         i = .25188917 * e(0, c, d, 0, "9", "23")
47     };
48     if (9 == c && d > 23 || c > 9 && c < 12 || 12 == c && d < 22) {
49         i = g(.26041667 * e(0, c, d, 0, "9", "23"))
50     };
51     if (12 == c && 22 == d) {
52         i = g(23.43333333)
53     };
54     if (12 == c && d > 22) {
55         i = g(.26315789 * e(0, c, d, 1, "3", "21"))
56     };
57     if (c < 3 || 3 == c && d < 21) {
58         i = g(.26315789 * e(0, c, d, 0, "3", "21"))
59     };
60     return f(h(a, i, b));
61 }