84 lines
2.5 KiB
Python
84 lines
2.5 KiB
Python
"""
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Misc utilities.
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"""
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from fractions import Fraction
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from typing import Optional, Tuple
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def _degrees_to_decimal(degrees: float, minutes: float, seconds: float) -> float:
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"""
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Converts coordinates from a degrees minutes seconds format to a decimal degrees format.
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Reference: https://en.wikipedia.org/wiki/Geographic_coordinate_conversion
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"""
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return degrees + minutes / 60 + seconds / 3600
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def get_gps_coords(tags: dict) -> Optional[Tuple[float, float]]:
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"""
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Extract tuple of latitude and longitude values in decimal degrees format from EXIF tags.
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Return None if no GPS coordinates are found.
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Handles regular and serialized Exif tags.
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"""
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gps = {
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"lat_coord": "GPS GPSLatitude",
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"lat_ref": "GPS GPSLatitudeRef",
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"lng_coord": "GPS GPSLongitude",
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"lng_ref": "GPS GPSLongitudeRef",
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}
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# Verify if required keys are a subset of provided tags
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if not set(gps.values()) <= tags.keys():
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return None
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# If tags have not been converted to native Python types, do it
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if not isinstance(tags[gps["lat_coord"]], list):
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tags[gps["lat_coord"]] = [c.decimal() for c in tags[gps["lat_coord"]].values]
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tags[gps["lng_coord"]] = [c.decimal() for c in tags[gps["lng_coord"]].values]
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tags[gps["lat_ref"]] = tags[gps["lat_ref"]].values
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tags[gps["lng_ref"]] = tags[gps["lng_ref"]].values
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lat = _degrees_to_decimal(*tags[gps["lat_coord"]])
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if tags[gps["lat_ref"]] == "S":
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lat *= -1
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lng = _degrees_to_decimal(*tags[gps["lng_coord"]])
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if tags[gps["lng_ref"]] == "W":
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lng *= -1
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return lat, lng
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class Ratio(Fraction):
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"""
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Ratio object that eventually will be able to reduce itself to lowest
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common denominator for printing.
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"""
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_numerator: Optional[int]
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_denominator: Optional[int]
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# We're immutable, so use __new__ not __init__
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def __new__(cls, numerator: int = 0, denominator: Optional[int] = None):
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try:
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self = super(Ratio, cls).__new__(cls, numerator, denominator)
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except ZeroDivisionError:
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self = super(Ratio, cls).__new__(cls)
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self._numerator = numerator
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self._denominator = denominator
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return self
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def __repr__(self) -> str:
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return str(self)
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@property
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def num(self) -> int:
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return self.numerator
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@property
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def den(self) -> int:
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return self.denominator
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def decimal(self) -> float:
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return float(self)
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