SunTimes : longitude, latitude and altitude

Calculation of sunrise and sunset time for a location (longitude, latitude, altitude) with python. Calculations valid beyond the polar circles ; returns Polar Day or Polar Night if necessary. Sunrise and sunset times also available for an entire year as a json or csv file.

Project description

This module contains functions to determine the time of sunset and the time of sunrise for a given day in a given location (longitude, latitude and altitude).
Times are calculated using data from Wikipedia.
The main functions return the times of sunset and sunrise in UTC or in local time. Additional functions return separately the hour and minute of sunrise and sunset. A function returns the length of the day. It is possible to obtain the timetables for a place in a different timezone, just by specifying this one.
The SunFiles class allows you to create and save a json or csv file with the timetables for a whole year.

Changes from version 0.2.2

• As the precision of the calculations is of the order of one to several minutes, it is useless to give the results to the nearest second.
• The calculations are valid beyond the polar circles. The closer you get to the poles, the lower the accuracy.

Installation

Required modules

suntimes module requires pytz, tzlocal, jdcal

$ pip install pytz

$ pip install tzlocal

$ pip install jdcal

Installation

The module can be installed using pip

$ pip install suntimes

Usage

Class SunTimes

place = SunTimes(longitude, latitude, altitude=0)

A place is characterized by longitude, latitude, altitude

• longitude: float between -180 and 180 ; negative for west longitudes, positive for east longitudes
• latitude: float between -90 and 90 ; positive if north, negative if south
• altitude: float, in meters; greater than or equal to zero. Default = 0.

Methods

Most of mehtods take a date as an argument.
The date will be a datetime.datetime in the format (yyyy, mm, dd), the time not important. Eg : datetime(2020, 12, 22).
Methods risewhere and setwhere take timezone as a second argument.
The timezone list is available on github.

Examples

Main methods

Import modules. Create an instance.

from datetime import datetime
from suntimes import SunTimes  
#date
day = datetime(2021,1,6)
#location Paris Notre-Dame France / Nuussuaq (Avannaata - Groenland)
sun = SunTimes(2.349902, 48.852968, 35)
polar = SunTimes(-57.06666667, 74.11666667)

Returns UTC time

sun.riseutc(day)
datetime.datetime(2021, 1, 6, 7, 43)
polar.riseutc(day)
'PN'

sun.setutc(day)
datetime.datetime(2021, 1, 6, 16, 12)

Returns local computer time

sun.riselocal(day)
datetime.datetime(2021, 1, 6, 8, 43, tzinfo=)

sun.setlocal(day)
datetime.datetime(2021, 1, 6, 17, 12, tzinfo=)
polar.setlocal(day)
'PN'

Separately hour and minute (local computer time)

sun.hrise(day)
8
sun.mrise(day)
43
sun.hset(day)
17
sun.mset(day)
12

Duration of the day

Returns the length of the day in a timedelta seconds, a tuple (hour, minute) or a verbose format. Teturn a string if polar day or polar night

sun.durationdelta(day)
datetime.timedelta(seconds=30540)
sun.durationtuple(day)
(8, 29)
sun.durationverbose(day)
'8h 29mn'

polar.durationdelta(day)
'Not calculable : PN'

Suntimes choosing the timezone

Sunrise and sunset in Sao Paulo (Brazil)

#location Sao Paulo, Brazil
sun = SunTimes(-46.63611, -23.5475, 769)
#sunrise and sunset in Sao Paulo, local computer time (France)
sun.riselocal(day)
datetime.datetime(2021, 1, 6, 9, 23, tzinfo=)
sun.setlocal(day)
datetime.datetime(2021, 1, 6, 23, 4, tzinfo=)
# sunrise and sunset in Sao Paulo, Sao Paulo time
sun.risewhere(day, 'America/Sao_Paulo')
datetime.datetime(2021, 1, 6, 5, 23, tzinfo=)
sun.setwhere(day, 'America/Sao_Paulo')
datetime.datetime(2021, 1, 6, 19, 4, tzinfo=)

Influence of altitude

Altitude can have an influence on the result. For example considering Mount Everst :

# Mount Everest, altitude = default (zero)
sun_0 = SunTimes(86.9246, 27.9891)
# Mount Everest, altitude = 8848
sun_8848 = SunTimes(86.9246, 27.9891, 8848)
# duration of the day, sun_0 and sun_8848
sun_0.durationverbose(day)
'10h 26mn'
sun_8848.durationverbose(day)
'10h 58mn'  

A difference of more than half an hour for the calculation of the length of the day.

Class SunFiles

file = SunFiles(place, year, place_verbose="")

where place is a SunTimes instance, year the year you choose and place_verbose the verbose name of the place.

Instantiation

from suntimes import SunTimes, SunFiles

place = SunTimes(2.349902, 48.852968, 35)
file = SunFiles(place, 2020, "Notre-Dame de Paris")

Methods

Get the data

place = SunTimes(2.349902, 48.852968, 35)
file = SunFiles(place, 2020, "Notre-Dame de Paris")
# Get json data : get_json(self, elsewhere = None)
file.get_json()
# Get csv data : get_csv(self)
file.get_csv()

Returns data with:

• month
• day
• hour, and minute of sunrise and sunset in utc, local computer time and specific timezone. If elswhere not specified, return utc, local computer time, local computer time again.
• schedules in a verbose mode (i.e. 8 h 12 mn)

Create and save the file

The data is calculated and the file created and saved.

register_json(self, path=None, file_name=None, elswhere=None)
register_csv(self, path=None, file_name=None, elswhere=None)

The path must be indicated correctly, otherwise an error is raised : /home/foo/Desktop/ or C:\Documents\Foo\Exercices\ for exemple. If file_name is not specified, it is generated automatically. For example : 2020_Notre-Dame_de_Paris_sun_timetable.csv

file.register_json(path="/home/foo/Desktop/", file_name="2020.json")
file.register_csv(path="/home/foo/Desktop/")

Read the file as a workbook

• CSV file is easy to open on a Excel xlsx or any other workbook.
• JSON file can be converted to xlsx here.

Duration of the days

Returns a list for the full year with day length, date by date. The result is as a list [year, month, day, hour, minute]

file.duration_days_year()
[[2020, 1, 1, 8, 22],
 [2020, 1, 2, 8, 23],
 [2020, 1, 3, 8, 24],
 .......
 [2020, 12, 29, 8, 20],
 [2020, 12, 30, 8, 21],
 [2020, 12, 31, 8, 22]]

Length of PolarDay/PolarNight

Returns the duration of the polar night and the duration of the polar day for a given year as a tuple:

• duration of the polar day in 24-hour daytime,
• duration of the polar night in 24-hour daytime

polarPlace = SunTimes(-57.06666667, 74.11666667)
polarFile = SunFiles(polarPlace, 2020, "Nuussuaq")
polarFile.PDPN_length()
(87, 103)

Start and end date of PolarDay/PolarNight

Returns the start and end date of the polar day and polar night, as a list of 4 tuples, each tuple including the month and day of the date. Returns a string if we are below the polar circles.

polarPlace = SunTimes(-57.06666667, 74.11666667)
polarFile = SunFiles(polarPlace, 2020, "Nuussuaq")
polarFile.PDPN_dates()
[(5, 1), (8, 11), (11, 8), (2, 2)]