def testTwoStations(self):
"""According to jan.ucc.nau.edu/~cvm/latlongdist, the distance
between Ithaca and Brewton is 1576.7066 km
"""
dist1 = compute_arc_dist(self.STATION_A, self.STATION_B)
dist2 = compute_arc_dist(self.STATION_B, self.STATION_A)
self.assertAlmostEquals(dist1, 1576.7066, delta=self.DELTA)
self.assertAlmostEquals(dist2, 1576.7066, delta=self.DELTA)
def find_neighborhood(station, stations_list, numsrt=40, mindist=200.0, **kwargs):
"""
Determines the neighborhood comprised of the closes numsrt neighbors located
around a given station.
:Param stations:
The candidate *Station* object.
:Param stations_list:
A list of *Station* objects to use to determine the neighborhood.
:Param numsrt:
The number of *Station* objects which should comprise the resulting
neighberhood.
:Param mindist:
The minimum distance to use while searching through the *Station* objects
iteratively. Most likely will not be used.
:Return:
The neighborhood as a list of two-element tuples. The tuples will each
be of the form (Station.coop_id, computed distance from candidate), and
the list will be sorted in descending order based on the computed
distance.
"""
neighbors = dict()
for other in stations_list:
if not station.coop_id == other.coop_id:
dist = compute_arc_dist(station, other)
neighbors[other.coop_id] = dist
# Sort the dictionary of neighbors into a list, sorting from least
# distance to greatest distances. Only take numsrt neighbors maximum.
sorted_neighbors = sorted(neighbors.iteritems(), key=itemgetter(1))[: numsrt - 1]
"""
# This code is actually superfluous, but it loops through the list of
# sorted neighbors, and finds only the neighbors which are within a maximum
# distance from the candidate station. When its done, it sees if there are
# enough neighbors, and if not, ups the threshold for distance and tries
# again.
close_neighbors = []
iter = 1
hidist = mindist
print "...searching for neighbors within %4.1fkm" % mindist
while (len(close_neighbors) < numsrt-1):
print "......iteration %d, %d neighbors found" % (iter,
len(close_neighbors))
for (coop_id, dist) in sorted_neighbors:
if dist < hidist:
sorted_neighbors.remove((coop_id, dist))
close_neighbors.append((coop_id, dist))
hidist = hidist+distinc
print ".........distance now %4.1fkm" % mindist
iter = iter+1
print "......ultimately found %d neighbors" % len(close_neighbors)
all_neighbors[coop_id1] = close_neighbors
"""
return sorted_neighbors
def testQuarterArc(self):
dist1 = compute_arc_dist(self.STATION_C, self.STATION_D)
dist2 = compute_arc_dist(self.STATION_D, self.STATION_C)
quarter_arc = (2.*pi*RADIUS_EARTH)/4.0
self.assertAlmostEquals(dist1, quarter_arc, delta=self.DELTA)
self.assertAlmostEquals(dist2, quarter_arc, delta=self.DELTA)
def testSameStation(self):
"""Distance between the same station should round off to 0."""
dist = compute_arc_dist(self.STATION_A, self.STATION_A)
self.assertAlmostEquals(dist, 0., delta=self.DELTA)
