C RUBY-ON-RAILS MYSQL ASP.NET DEVELOPMENT RUBY .NET LINUX SQL-SERVER REGEX WINDOWS ALGORITHM ECLIPSE VISUAL-STUDIO STRING SVN PERFORMANCE APACHE-FLEX UNIT-TESTING SECURITY LINQ UNIX MATH EMAIL OOP LANGUAGE-AGNOSTIC VB6 MSBUILD

# How to convert UTC and longitude to mean solar local time python

By : Gabriel Gamez
Date : November 19 2020, 03:01 PM
I wish this helpful for you Explanatory Supplement to the Astronomical Almanac 3rd ed. page 239 states that the local mean solar time, LMSoT, is related to UT and the observer's east longitude by
LMSoT = UT + ƛ
code :

Share :

## Calculate "Solar Noon" using ephem, translating to local time

By : OxygenSupply
Date : March 29 2020, 07:55 AM
I wish did fix the issue. Solar noon is not the mean of sunrise and sunset (see equation of time for the explanation). The ephem package has methods for getting transit times which you should use instead:
code :
``````>>> import ephem
>>> o = ephem.Observer()
>>> o.lat, o.long = '37.0625', '-95.677068'
>>> sun = ephem.Sun()
>>> sunrise = o.previous_rising(sun, start=ephem.now())
>>> noon = o.next_transit(sun, start=sunrise)
>>> sunset = o.next_setting(sun, start=noon)
>>> noon
2010/11/6 18:06:21
>>> ephem.date((sunrise + sunset) / 2)
2010/11/6 18:06:08
``````

## Local solar time function from UTC and longitude

By : Manasa Pyla
Date : March 29 2020, 07:55 AM
This might help you Or if you want to go even shorter, you could use NOAA's low-accuracy equations:
code :
``````#!/usr/local/bin/python

import sys
from datetime import datetime, time, timedelta
from math import pi, cos, sin

def solar_time(dt, longit):
return ha

def main():
if len(sys.argv) != 4:
print 'Usage: hour_angle.py [YYYY/MM/DD] [HH:MM:SS] [longitude]'
sys.exit()
else:
dt = datetime.strptime(sys.argv[1] + ' ' + sys.argv[2], '%Y/%m/%d %H:%M:%S')
longit = float(sys.argv[3])

gamma = 2 * pi / 365 * (dt.timetuple().tm_yday - 1 + float(dt.hour - 12) / 24)
eqtime = 229.18 * (0.000075 + 0.001868 * cos(gamma) - 0.032077 * sin(gamma) \
- 0.014615 * cos(2 * gamma) - 0.040849 * sin(2 * gamma))
decl = 0.006918 - 0.399912 * cos(gamma) + 0.070257 * sin(gamma) \
- 0.006758 * cos(2 * gamma) + 0.000907 * sin(2 * gamma) \
- 0.002697 * cos(3 * gamma) + 0.00148 * sin(3 * gamma)
time_offset = eqtime + 4 * longit
tst = dt.hour * 60 + dt.minute + dt.second / 60 + time_offset
solar_time = datetime.combine(dt.date(), time(0)) + timedelta(minutes=tst)
print solar_time

if __name__ == '__main__':
main()
``````

## convert to local time zone using latitude and longitude?

By : user7812649
Date : March 29 2020, 07:55 AM
I hope this helps . I have a data set with the following information: latitude, longitude, EST time. For example, for one observation
code :
``````lat = 13
long = -2
time1 <- as.POSIXct("2014-02-12 17:00:00", tz = "EST")
"xml",
lat,
long,
as.numeric(time1),
"false")
library(XML)
as.POSIXct(format(time1, tz=tz))
# [1] "2014-02-12 22:00:00 CET"
``````
``````res <- googleway::google_timezone(c(lat, long), time1, key = NULL)
as.POSIXct(format(time1, tz=res\$timeZoneId))
# [1] "2014-02-12 22:00:00 CET"
``````

## How to take a datetime.time object in UT and convert to local time given a longitude

By : Kduk Reg
Date : March 29 2020, 07:55 AM
it should still fix some issue I need to convert a time in UT combined with a longitude into local time. I am working on analyzing a future Earth observing satellite mission and need to do this conversion to continue. , I figured it out but it is not pretty.
code :
``````localtimes = []
for (i,j) in zip(sattime, satloncor):
td = dt.datetime.combine(dt.datetime.min, i) - dt.datetime.min
seconds = td  // dt.timedelta(seconds=1)
local = (seconds + (j/(360/86400)))/3600
if local>24:
local-=24
strip = [math.modf(local)[1],math.modf(local)[0]*60 ]
if strip[0]==24:
localtimes.append(dt.time(0, int(strip[1]),0))
else:
localtimes.append(dt.time(int(strip[0]), int(strip[1]),0))
``````

## Convert to local time zone from latitude and longitude R

By : user3605375
Date : March 29 2020, 07:55 AM
should help you out I think this is what you want. I first created a date object. Then, I searched time zones with tz_lookup_coords() as you were trying. Then, I used with_tz(), which gets date-time in a different time zone. Note that new_time is a list as str(dt) indicates.
code :
``````library(data.table)
library(lutz)
library(purrr)
library(lubridate)

dt[, date := as.POSIXct(date, format = "%Y-%m-%d %H:%M:%S", tz = "GMT")][,
timezone := tz_lookup_coords(lat = lat, lon = long, method = "accurate")][,
new_time := map2(.x = date, .y = timezone,
.f = function(x, y) {with_tz(time = x, tzone = y)})][]

#                  date      lat     long  timezone            new_time
#1: 2018-01-16 22:02:37 -54.5010 -25.0433 Etc/GMT+2 2018-01-16 20:02:37
#2: 2018-01-16 22:54:00 -54.5246 -25.0929 Etc/GMT+2 2018-01-16 20:54:00
#3: 2018-01-16 23:08:38 -54.5285 -25.0832 Etc/GMT+2 2018-01-16 21:08:38

#str(dt)
#Classes ‘data.table’ and 'data.frame': 3 obs. of  5 variables:
# \$ date    : POSIXct, format: "2018-01-16 22:02:37" "2018-01-16 22:54:00" "2018-01-16 23:08:38"
# \$ lat     : num  -54.5 -54.5 -54.5
# \$ long    : num  -25 -25.1 -25.1
# \$ timezone: chr  "Etc/GMT+2" "Etc/GMT+2" "Etc/GMT+2"
# \$ new_time:List of 3
#  ..\$ : POSIXct, format: "2018-01-16 20:02:37"
#  ..\$ : POSIXct, format: "2018-01-16 20:54:00"
#  ..\$ : POSIXct, format: "2018-01-16 21:08:38"
``````
``````setDF(dt) %>%
mutate(date = as.POSIXct(date, format = "%Y-%m-%d %H:%M:%S", tz = "GMT"),
timezone = tz_lookup_coords(lat = lat, lon = long, method = "accurate"),
new_time = map2(.x = date, .y = timezone,
.f = function(x, y) {with_tz(time = x, tzone = y)})) %>%
unnest(new_time)

date                  lat  long timezone  new_time
<dttm>              <dbl> <dbl> <chr>     <dttm>
1 2018-01-16 22:02:37 -54.5 -25.0 Etc/GMT+2 2018-01-16 20:02:37
2 2018-01-16 22:54:00 -54.5 -25.1 Etc/GMT+2 2018-01-16 20:54:00
3 2018-01-16 23:08:38 -54.5 -25.1 Etc/GMT+2 2018-01-16 21:08:38

> str(foo)
Classes ‘tbl_df’, ‘tbl’ and 'data.frame':   3 obs. of  5 variables:
\$ date    : POSIXct, format: "2018-01-16 22:02:37" "2018-01-16 22:54:00" "2018-01-16 23:08:38"
\$ lat     : num  -54.5 -54.5 -54.5
\$ long    : num  -25 -25.1 -25.1
\$ timezone: chr  "Etc/GMT+2" "Etc/GMT+2" "Etc/GMT+2"
\$ new_time: POSIXct, format: "2018-01-16 20:02:37" "2018-01-16 20:54:00" "2018-01-16 21:08:38"
``````