133 lines
3.7 KiB
Python
133 lines
3.7 KiB
Python
from math import radians, cos, sin, asin, sqrt, trunc, floor, ceil
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EARTH_RADIUS_KM = 6371
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class Coordinates(object):
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"""
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A helper class for GPS coordinates.
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"""
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def __init__(self, lat=0, lng=0):
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"""
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Get coordinates from decimal degrees.
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:param float lat: Latitude in decimal degrees.
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:param float lng: Longitude in decimal degrees.
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"""
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self.lat = lat
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self.lng = lng
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def __repr__(self):
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return '{}(lat={}, lng={})'.format(
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self.__class__.__name__, self.lat, self.lng)
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def __str__(self):
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return ', '.join(tuple(self))
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def __hash__(self):
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return hash(tuple(self))
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def __len__(self):
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return 2
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def __length_hint__(self):
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return len(self)
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def __iter__(self):
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return (self.lat, self.lng)
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def __dict__(self):
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return {'lat': self.lat, 'lng': self.lng}
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def __eq__(self, other):
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return hasattr(other, 'lat') and hasattr(other, 'lng') and \
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tuple(self) == tuple(other)
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def __add__(self, other):
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if not hasattr(other, 'lat') or hasattr(other, 'lng'):
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return NotImplemented
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return self.__class__(
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lat=self.lat + other.lat,
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lng=self.lng + other.lng,
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)
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def __sub__(self, other):
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if not hasattr(other, 'lat') or hasattr(other, 'lng'):
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return NotImplemented
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return self.__class__(
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lat=self.lat - other.lat,
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lng=self.lng - other.lng,
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)
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def __pos__(self):
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return self
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def __neg__(self):
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return self.__class__(lat=-self.lat, lng=-self.lng)
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def __abs__(self):
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return self.__class__(lat=abs(self.lat), lng=abs(self.lng))
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def __round__(self, ndigits=None):
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return self.__class__(
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lat=round(self.lat, ndigits),
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lng=round(self.lng, ndigits),
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)
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def __trunc__(self):
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return self.__class__(lat=trunc(self.lat), lng=trunc(self.lng))
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def __floor__(self):
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return self.__class__(lat=floor(self.lat), lng=floor(self.lng))
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def __ceil__(self):
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return self.__class__(lat=ceil(self.lat), lng=ceil(self.lng))
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def to_radians(self):
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"""
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Convert to a ``(lat, lng)`` tuple in radians.
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:returns: Coordinates in radians.
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:rtype: tuple(float, float)
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"""
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return tuple(map(radians, self))
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def distance(self, other):
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"""
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Compute Haversine distance between two coordinates in meters.
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:param other: Another pair of coordinates to compute distance against.
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:type other: Coordinates
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:returns: Distance between the two coordinates, in meters.
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:rtype: float
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"""
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if not hasattr(other, 'to_radians'):
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raise NotImplementedError(
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'Distance requires a to_radians() method on both coordinates')
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lat1, lon1 = self.to_radians()
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lat2, lon2 = other.to_radians()
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dlon, dlat = lon2 - lon1, lat2 - lat1
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a = sin(dlat / 2) ** 2 + cos(lat1) * cos(lat2) * sin(dlon / 2) ** 2
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return EARTH_RADIUS_KM * 2000 * asin(sqrt(a))
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def toJSON(self):
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"""
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Convert to UrbanTZ JSON geometry
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:returns: UrbanTZ-compatible JSON geometry data
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:rtype: list(float)
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"""
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return [self.lng, self.lat]
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@staticmethod
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def fromJSON(geometry):
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"""
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Get a Coordinates instance from parsed UrbanTZ JSON geometry data.
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:param geometry: Parsed UrbanTZ geometry data: a list holding
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``[lng, lat]`` in decimal degrees.
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:type geometry: list(float)
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"""
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return Coordinates(lng=geometry[0], lat=geometry[1])
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