javascript - Javascript 或 Python - 我如何判断是白天还是黑夜？

Question

知道如何根据用户的时间和位置确定当前是晚上/白天还是日出/黎明？

我还没有发现可以在客户端或后端使用的任何有用的东西。

让它变得棘手的是小时不一定定义它是白天还是黑夜，这在很大程度上取决于年、月、日、小时和地理坐标。

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为了澄清......模仿这样的事情。

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一种近似这一点的方法也将非常有用。

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希望有人能帮忙！

Answer 1

Python 3 用户注意：我刚刚使用 Python 3.8.6 尝试了以下代码，它也适用于该版本。我必须将print语句转换为print()函数调用，但仅此而已。

我注意到tzinfo类的示例实现与 Python 2 文档中的不同，但是使用最新文档中引用的tzinfo_example.py文件中的示例tzinfo类工作得很好（但旧的 2.x 版本也是如此）。

您可以从此处sunriseset.py下载下面显示的文件的 Python 3 版本。

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你可以像我一样使用这个公共领域的Sun.py模块来计算太阳相对于地球位置的位置。（警告：它包含制表符并假设制表符每 8 个字符。）它已经很老了，但多年来一直对我很好。我对其进行了一些表面上的修改，以使其与 Python 2.7 保持同步，例如将其中的几个类设为新样式，但在大多数情况下它没有改变。

这是我创建的一个模块，称为sunriseset.py，它展示了如何使用它来计算给定地理坐标和时区的特定位置的日出和日落时间。被引用的timezone模块是模块的对象tzinfo文档中描述的抽象基类的实现。datetimetzinfo

# -*- coding: iso-8859-1 -*-
import datetime
import timezone  # concrete tzinfo subclass based on the Python docs
import math
from Sun import Sun

__all__ = ['getsuninfo', 'Place']

class Place(object):
    def __init__(self, name, coords, tz=timezone.Pacific):
        self.name = name        # string
        self.coords = coords    # tuple (E/W long, N/S lat)
        self.tz = tz            # tzinfo constant

def _hoursmins(hours):
    """Convert floating point decimal time in hours to integer hrs,mins"""
    frac,h = math.modf(hours)
    m = round(frac*60, 0)
    if m == 60: # rounded up to next hour
        h += 1; m = 0
    return int(h),int(m)

def _ymd(date):
    """Return y,m,d from datetime object as tuple"""
    return date.timetuple()[:3]

def getsuninfo(location, date=None):
    """Return local datetime of sunrise, sunset, and length of day in hrs,mins)"""
    if date == None:
        querydate = datetime.date.today()
    else: # date given should be datetime instance
        querydate = date

    args = _ymd(querydate) + location.coords
    utcrise, utcset = Sun().sunRiseSet(*args)
    daylength = Sun().dayLength(*args)
    hrs,mins = _hoursmins(daylength)

    risehour, risemin = _hoursmins(utcrise)
    sethour, setmin   = _hoursmins(utcset)

    # convert times to timedelta values (ie from midnight utc of the date)
    midnight = datetime.datetime(tzinfo=timezone.utc, *_ymd(querydate))
    deltarise = datetime.timedelta(hours=risehour, minutes=risemin)
    utcdatetimerise = midnight+deltarise
    deltaset = datetime.timedelta(hours=sethour, minutes=setmin)
    utcdatetimeset  = midnight+deltaset

    # convert results from UTC time to local time of location
    localrise = utcdatetimerise.astimezone(location.tz)
    localset  = utcdatetimeset.astimezone(location.tz)

    return localrise, localset, hrs, mins

if __name__ == "__main__":
    import datetime, timezone

    def unittest(location, testdate):
        risetime, settime, hrs, mins = getsuninfo(location, testdate)

        print "Location:", location.name
        print "Date:", testdate.strftime("%a %x")
        print risetime.strftime("Sunrise %I:%M %p"), settime.strftime("- Sunset %I:%M %p (%Z)")
        print "daylight: %d:%02d" % (hrs,mins)
        print

    place = Place("My House", (-121.990278, 47.204444), timezone.Pacific)

    # test dates just before and after DST transitions
    print "pre 2007"
    print "========="
    unittest(place, datetime.date(2006, 4, 1))
    unittest(place, datetime.date(2006, 4, 2))
    unittest(place, datetime.date(2006, 10, 28))
    unittest(place, datetime.date(2006, 10, 29))

    print "2007"
    print "========="
    unittest(place, datetime.date(2007, 3, 10))
    unittest(place, datetime.date(2007, 3, 11))
    unittest(place, datetime.date(2007, 11, 3))
    unittest(place, datetime.date(2007, 11, 4))

Answer 2

美国海军天文台提供了计算日出和日落的算法的简明描述，可在此处获得：

http://edwilliams.org/sunrise_sunset_algorithm.htm

除了提供日期和位置外，您还需要选择天顶角（太阳将被视为“升起”或“落下”的天顶角）- 链接的页面有多个选项。

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更新

由于链接页面不再可用，我在下面引用其文本。请注意，其中包含的公式采用类似伪代码的形式，而不是 JavaScript。

Source:
    Almanac for Computers, 1990
    published by Nautical Almanac Office
    United States Naval Observatory
    Washington, DC 20392

Inputs:
    day, month, year:      date of sunrise/sunset
    latitude, longitude:   location for sunrise/sunset
    zenith:                Sun's zenith for sunrise/sunset
      offical      = 90 degrees 50'
      civil        = 96 degrees
      nautical     = 102 degrees
      astronomical = 108 degrees

    NOTE: longitude is positive for East and negative for West
        NOTE: the algorithm assumes the use of a calculator with the
        trig functions in "degree" (rather than "radian") mode. Most
        programming languages assume radian arguments, requiring back
        and forth convertions. The factor is 180/pi. So, for instance,
        the equation RA = atan(0.91764 * tan(L)) would be coded as RA
        = (180/pi)*atan(0.91764 * tan((pi/180)*L)) to give a degree
        answer with a degree input for L.


1. first calculate the day of the year

    N1 = floor(275 * month / 9)
    N2 = floor((month + 9) / 12)
    N3 = (1 + floor((year - 4 * floor(year / 4) + 2) / 3))
    N = N1 - (N2 * N3) + day - 30

2. convert the longitude to hour value and calculate an approximate time

    lngHour = longitude / 15

    if rising time is desired:
      t = N + ((6 - lngHour) / 24)
    if setting time is desired:
      t = N + ((18 - lngHour) / 24)

3. calculate the Sun's mean anomaly

    M = (0.9856 * t) - 3.289

4. calculate the Sun's true longitude

    L = M + (1.916 * sin(M)) + (0.020 * sin(2 * M)) + 282.634
    NOTE: L potentially needs to be adjusted into the range [0,360) by adding/subtracting 360

5a. calculate the Sun's right ascension

    RA = atan(0.91764 * tan(L))
    NOTE: RA potentially needs to be adjusted into the range [0,360) by adding/subtracting 360

5b. right ascension value needs to be in the same quadrant as L

    Lquadrant  = (floor( L/90)) * 90
    RAquadrant = (floor(RA/90)) * 90
    RA = RA + (Lquadrant - RAquadrant)

5c. right ascension value needs to be converted into hours

    RA = RA / 15

6. calculate the Sun's declination

    sinDec = 0.39782 * sin(L)
    cosDec = cos(asin(sinDec))

7a. calculate the Sun's local hour angle

    cosH = (cos(zenith) - (sinDec * sin(latitude))) / (cosDec * cos(latitude))

    if (cosH >  1) 
      the sun never rises on this location (on the specified date)
    if (cosH < -1)
      the sun never sets on this location (on the specified date)

7b. finish calculating H and convert into hours

    if if rising time is desired:
      H = 360 - acos(cosH)
    if setting time is desired:
      H = acos(cosH)

    H = H / 15

8. calculate local mean time of rising/setting

    T = H + RA - (0.06571 * t) - 6.622

9. adjust back to UTC

    UT = T - lngHour
    NOTE: UT potentially needs to be adjusted into the range [0,24) by adding/subtracting 24

10. convert UT value to local time zone of latitude/longitude

    localT = UT + localOffset

Answer 3

PyEphem可用于计算下一次日出和日落的时间。基于我发现的一篇博客文章和rise-set 的文档，您的问题可以通过以下方式解决。假设我是您的用户，我的位置是德国奥尔登堡 (Oldb)。

import ephem

user = ephem.Observer()
user.lat = '53.143889'    # See wikipedia.org/Oldenburg
user.lon = '8.213889'     # See wikipedia.org/Oldenburg
user.elevation = 4        # See wikipedia.org/Oldenburg
user.temp = 20            # current air temperature gathered manually
user.pressure = 1019.5    # current air pressure gathered manually

next_sunrise_datetime = user.next_rising(ephem.Sun()).datetime()
next_sunset_datetime = user.next_setting(ephem.Sun()).datetime()

# If it is daytime, we will see a sunset sooner than a sunrise.
it_is_day = next_sunset_datetime < next_sunrise_datetime
print("It's day." if it_is_day else "It's night.")

# If it is nighttime, we will see a sunrise sooner than a sunset.
it_is_night = next_sunrise_datetime < next_sunset_datetime
print("It's night." if it_is_night else "It's day.")

笔记

• 出于某种原因lat，lon需要是字符串，但如果它们是浮点数，ephem 不会抱怨。
• 为获得最佳结果，您可能需要获取当前气温和气压。

先决条件

这应该至少适用于 Python 2.7 (with pip-2.7 install pyephem) 和 Python 3.2 (with pip-3.2 install ephem)。

确保在系统上运行网络时间协议客户端。例如在 Debian Linux 上：

$ sudo apt-get install ntp
$ sudo /etc/init.d/ntp start

确保在您的系统上设置了正确的时区。例如在 Debian Linux 上：

$ sudo dpkg-reconfigure tzdata

Answer 4

您可以使用包含所有关于日落和日出的精确数据的祈祷 api，然后通过用户本地化将它们与实际时间进行比较，Api Link

您可以使用此功能仅通过经度和纬度来确定是白天还是黑夜

代码

from timezonefinder import TimezoneFinder
import requests
from datetime import datetime, timezone
import pytz

def TimeEstimation(lat,lng):
    '''function to check DAY/NIGHT for a particular localisation'''
    obj = TimezoneFinder()
    result = obj.timezone_at(lng=lng, lat=lat)
    timezone =  pytz.timezone(result)
    hour = str(datetime.now(timezone).hour)
    minute = str(datetime.now(timezone).minute)
    
    actual_time = datetime.strptime(hour+":"+minute,'%H:%M')
    
    #asking salat api to get sunset and sunrise time based on longitude and latitude
    
    response = requests.get("https://api.pray.zone/v2/times/today.json?longitude="+str(lng)+"&latitude="+str(lat)+"&elevation=0")
    api_data = response.json()
    sunset = api_data.get("results").get("datetime")[0].get("times").get("Sunset")
    sunset=datetime.strptime(sunset,'%H:%M')
    
    sunrise = api_data.get("results").get("datetime")[0].get("times").get("Imsak")
    sunrise=datetime.strptime(sunrise,'%H:%M')

    if actual_time >= sunset or actual_time <= sunrise:
        print("is night")
        return(False)

    else:
        print("is day")
        return(True)