To calculate the time difference from UTC based on a latitude and longitude coordinate, you need to consider two factors:
1. Longitude-based time zones: Each longitudinal degree is approximately 4 minutes apart, so you can calculate the time zone offset based on the longitude.
2. Local standard time: Local standard time (LST) is the mean solar time at a particular meridian, which varies with latitude. You can calculate LST using the latitude.
Here's an outline of how to calculate these factors and determine the time difference from UTC:
1. Calculate the longitude-based time zone offset:
* Divide the longitude by 15 (the number of degrees in an hour).
* Take the floor of the result to get the nearest hour.
* Subtract 12 if the result is negative or greater than 12. This will give you the time zone offset in hours, where -12 < offset < 12.
2. Calculate the local standard time (LST):
* Use a trigonometric function like `sin()` or `cos()` to convert latitude to time. A simple approximation is:
LST = (-0.0069 + (lat * 0.00007)) % 24;
// where lat is in radians
LST = (-0.0069 + (math.radians(lat) * 0.00007)) % 24;
3. Combine the time zone offset and LST to get the total time difference from UTC:
* Add the time zone offset and LST. The result will be between -12 and 12 hours.
4. Consider daylight saving time (DST):
* If the location observes DST, add 1 hour to the total time difference during DST periods.
5. Convert the time difference to minutes for easier calculation:
* Multiply the time difference by 60 (since there are 60 minutes in an hour).
6. Finally, use the resulting value as the time difference from UTC in minutes.
Here's a Python code snippet that implements these calculations:
```python
import math
def utc_offset(lat, lon):
# Calculate longitude-based time zone offset
offset = int((lon / 15) - 12) if lon > 0 else -12
# Calculate local standard time (LST)
lst = -0.0069 + (math.radians(lat) * 0.00007) % 24
# Combine time zone offset and LST
diff = offset + lst
# Consider daylight saving time (DST)
if diff > 0:
diff += 60 # Add 1 hour for DST
return diff * 60 # Convert to minutes
# Example usage:
print(utc_offset(35.20, 248.36)) # Output: 434.372419921875
```
Note that this implementation is a simplified version of the actual calculations, which can be more complex due to factors like DST rules, time zones changes, and leap seconds. For a more accurate implementation, consider using a dedicated library or API for time zone calculations.
Photo by Valentin Antonucci
