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通过经纬度计算日升日落时间

通过经纬度计算日升日落时间

作者: yang_fy | 来源:发表于2018-07-20 13:31 被阅读73次

    // 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。。。

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