77 lines
2.3 KiB
Python
77 lines
2.3 KiB
Python
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import unittest
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from cartodb_services.mapzen import MapzenIsolines
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from math import radians, cos, sin, asin, sqrt
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"""
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This file is basically a sanity test on the algorithm.
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It uses a mocked client, which returns the cost based on a very simple model:
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just proportional to the distance from origin to the target point.
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"""
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class MatrixClientMock():
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def __init__(self, speed):
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"""
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Sets up the mock with a speed in km/h
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"""
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self._speed = speed
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def one_to_many(self, locations, costing):
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origin = locations[0]
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distances = [self._distance(origin, l) for l in locations]
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response = {
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'one_to_many': [
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[
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{
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'distance': distances[i] * self._speed,
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'time': distances[i] / self._speed * 3600,
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'to_index': i,
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'from_index': 0
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}
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for i in xrange(0, len(distances))
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]
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],
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'units': 'km',
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'locations': [
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locations
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]
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}
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return response
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def _distance(self, a, b):
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"""
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Calculate the great circle distance between two points
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on the earth (specified in decimal degrees)
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http://stackoverflow.com/questions/4913349/haversine-formula-in-python-bearing-and-distance-between-two-gps-points
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Returns:
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distance in meters
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"""
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# convert decimal degrees to radians
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lon1, lat1, lon2, lat2 = map(radians, [a['lon'], a['lat'], b['lon'], b['lat']])
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# haversine formula
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dlon = lon2 - lon1
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dlat = lat2 - lat1
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a = sin(dlat/2)**2 + cos(lat1) * cos(lat2) * sin(dlon/2)**2
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c = 2 * asin(sqrt(a))
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r = 6371 # Radius of earth in kilometers. Use 3956 for miles
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return c * r
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class MapzenIsolinesTestCase(unittest.TestCase):
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def setUp(self):
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speed = 6 # in km/h
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matrix_client = MatrixClientMock(speed)
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self.mapzen_isolines = MapzenIsolines(matrix_client)
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def test_calculate_isochrone(self):
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origin = {"lat":40.744014,"lon":-73.990508}
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transport_mode = 'walk'
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isorange = 10 * 60 # 10 minutes
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solution = self.mapzen_isolines.calculate_isochrone(origin, transport_mode, isorange)
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