from astropy import units as u
from astropy.coordinates import EarthLocation
from datetime import datetime
import pytz
import tzlocal
def validate_coordinates(lat: float, lon: float) -> bool:
"""Validate latitude and longitude values."""
return -90 <= lat <= 90 and -180 <= lon <= 180
def create_earth_location(lat: float, lon: float, elevation: float = 0.0) -> EarthLocation:
"""Create an EarthLocation object from coordinates."""
if not validate_coordinates(lat, lon):
raise ValueError(f"Invalid coordinates: lat={lat}, lon={lon}")
return EarthLocation(lat=lat * u.deg, lon=lon * u.deg, height=elevation * u.m)
def parse_datetime(date_str: str, time_str: str, timezone: str = "UTC") -> datetime:
"""
Parse a date string into a timezone-aware datetime object.
Note: Uses `pytz.timezone` for compatibility, but avoids direct comparison of tzinfo objects.
"""
try:
tz = pytz.timezone(timezone)
naive_dt = datetime.strptime(date_str, "%Y-%m-%d")
return tz.localize(naive_dt)
except (ValueError, pytz.exceptions.UnknownTimeZoneError) as e:
raise ValueError(f"Invalid input: {e}")
def localtime_to_utc(local_dt: datetime) -> datetime:
"""
Convert a timezone-aware local datetime to UTC.
Args:
local_dt: Timezone-aware datetime object (e.g., from `parse_datetime`).
Returns:
datetime: UTC datetime (timezone-aware).
Raises:
ValueError: If input datetime is naive (not timezone-aware).
"""
if local_dt.tzinfo is None:
raise ValueError("Input datetime must be timezone-aware.")
return local_dt.astimezone(pytz.UTC)
