// 通过经纬度获取日出日落时间
// 纬度、精度、时区
computeSunRiseSunSet(Latitude, Longitude, TimeZone) {
function parseTime(aTime) {
var aDateTimeObject = 'none';
if (aTime !== undefined && aTime.length) {
var aDate = new Date();
var aDateAdjustedToGMTInMS = aDate.getTime() + (aDate.getTimezoneOffset() * 60 * 1000);
aDateTimeObject = new Date(aDateAdjustedToGMTInMS);
try {
var theHour = parseInt(aTime.split(':')[0]);
var theMinutes = parseInt(aTime.split(':')[1]);
aDateTimeObject.setHours(theHour);
aDateTimeObject.setMinutes(theMinutes);
} catch (ex) {}
}
return aDateTimeObject;
}
var curTime = new Date();
// Variable names used: B5, C, C2, C3, CD, D, DR, H, HR, HS, L0, L5, M, MR, MS, N, PI, R1, RD, S1, SC, SD, str
var retVal = new Object();
var PI = Math.PI;
var DR = PI / 180;
var RD = 1 / DR;
var B5 = Latitude;
var L5 = Longitude;
var H = -1 * (curTime.getTimezoneOffset() / 60 * -1); // Local timezone
// Overriding TimeZone to standardize on UTC
// H = 0;
var M = curTime.getMonth() + 1;
var D = curTime.getDate();
B5 = DR * B5;
var N = parseInt(275 * M / 9) - 2 * parseInt((M + 9) / 12) + D - 30;
var L0 = 4.8771 + .0172 * (N + .5 - L5 / 360);
var C = .03342 * Math.sin(L0 + 1.345);
var C2 = RD * (Math.atan(Math.tan(L0 + C)) - Math.atan(.9175 * Math.tan(L0 + C)) - C);
var SD = .3978 * Math.sin(L0 + C);
var CD = Math.sqrt(1 - SD * SD);
var SC = (SD * Math.sin(B5) + .0145) / (Math.cos(B5) * CD);
if (Math.abs(SC) <= 1) {
var C3 = RD * Math.atan(SC / Math.sqrt(1 - SC * SC));
var R1 = 6 - H - (L5 + C2 + C3) / 15;
var HR = parseInt(R1);
var MR = parseInt((R1 - HR) * 60);
retVal.SunRise = parseTime(HR + ":" + MR);
var TargetTimezoneOffset = (TimeZone * 60 * 60 * 1000) + (retVal.SunRise.getTimezoneOffset() * 60 * 1000);
var transformedSunRise = new Date(retVal.SunRise.getTime() + TargetTimezoneOffset);
var strSunRise = transformedSunRise.getHours() + ":" + (transformedSunRise.getMinutes() < 10 ? "0" + transformedSunRise.getMinutes() : transformedSunRise.getMinutes());
var S1 = 18 - H - (L5 + C2 - C3) / 15;
var HS = parseInt(S1);
var MS = parseInt((S1 - HS) * 60);
retVal.SunSet = parseTime(HS + ":" + MS);
var transformedSunSet = new Date(retVal.SunSet.getTime() + TargetTimezoneOffset);
var strSunSet = transformedSunSet.getHours() + ":" + (transformedSunSet.getMinutes() < 10 ? "0" + transformedSunSet.getMinutes() : transformedSunSet.getMinutes());
retVal.Noon = new Date((retVal.SunRise.getTime() + retVal.SunSet.getTime()) / 2);
var transformedNoon = new Date(retVal.Noon.getTime() + TargetTimezoneOffset);
var strNoon = transformedNoon.getHours() + ":" + (transformedNoon.getMinutes() < 10 ? "0" + transformedNoon.getMinutes() : transformedNoon.getMinutes());
} else {
if (SC > 1) {
// str="Sun up all day";
strSunRise = ".";
strNoon = ".";
strSunSet = ".";
var tDate = new Date();
// Set Sunset to be in the future ...
retVal.SunSet = new Date(tDate.getFullYear() + 1, tDate.getMonth(), tDate.getDay(), tDate.getHours());
// Set Sunrise to be in the past ...
retVal.SunRise = new Date(tDate.getFullYear() - 1, tDate.getMonth(), tDate.getDay(), tDate.getHours() - 1);
}
if (SC < -1) {
// str="Sun down all day";
strSunRise = ".";
strNoon = ".";
strSunSet = ".";
// Set Sunrise and Sunset to be in the future ...
retVal.SunRise = new Date(tDate.getFullYear() + 1, tDate.getMonth(), tDate.getDay(), tDate.getHours());
retVal.SunSet = new Date(tDate.getFullYear() + 1, tDate.getMonth(), tDate.getDay(), tDate.getHours());
}
}
retVal.strSunRise = strSunRise;
retVal.strNoon = strNoon;
retVal.strSunSet = strSunSet;
retVal.str = "日出" + strSunRise + ' | ' + "正午" + strNoon + ' | ' + "日落" + strSunSet;
return retVal;
}
}
ps：非原创，但忘记原文链接了。。。
