def findMatchingShapeIndex(self,stop,begin_idx=0,tol=20):
## Given a stop, finds the first shape segment at
## index i >= begin_idx that is within tol meters
## of the stop's location.
last_pt = self.shape[begin_idx]
min_dist,min_pt = 1e10,None
for i,pt in enumerate(self.shape[begin_idx+1:]):
dist = gis.distance_from_segment_meters( (last_pt['shape_pt_lat'],
last_pt['shape_pt_lon']),
(pt['shape_pt_lat'],
pt['shape_pt_lon']),
(stop['stop_lat'],
stop['stop_lon']) );
if dist <= tol:
return i+begin_idx; #really it's i+begin_idx+1 - 1
if dist < min_dist:
min_dist,min_pt = dist,pt
last_pt = pt
print "Returning none (DOH!)"
print " Min dist was %f meters" % (min_dist,)
return None
def getTimesAtLocation(self,stoploc,tol=10.0,starttime=None,findjustone=False):
"""
Given a (lat,lon), returns a list of (begin,end,dist) intervals of the
(estimated) times that the bus was within tol meters of that
location, starting at starttime. The 'dist' part of each interval
indicates the estimated minimum distance of the bus from stoploc during
that interval.
If starttime is None, then defaults to the beginning of the track.
If findjustone is True, returns after finding the first complete interval.
"""
in_range = False
current_interval = None # will be [begin,end,dist] holder
ret = []
if starttime is None: starttime = self.min_time;
starttime = max(starttime,self.min_time);
if starttime > self.max_time:
return ret
## Process intersection at first sub-segment
startloc = self.getLocationAtTime(starttime);
ll1 = startloc
ll2 = self.interpolation[self.cached_index+1][:2]
t1,t2 = starttime, self.interpolation[self.cached_index+1][2]
overall_min_dist = gis.distance_from_segment_meters( ll1, ll2, stoploc )
intersect = gis.distance_intersect( ll1, ll2, stoploc, tol )
if intersect:
enter_frac,exit_frac,min_dist = intersect
enter_time = gis.timefrac_helper( t1,t2,enter_frac )
exit_time = gis.timefrac_helper( t1,t2,exit_frac )
if exit_frac == 1.0:
current_interval = [ enter_time, exit_time, min_dist ]
in_range = True
else:
ret.append([ enter_time, exit_time, min_dist ])
## Process subsequent segments
for i in range(self.cached_index+1, len(self.interpolation)-1):
llt1 = self.interpolation[i]
llt2 = self.interpolation[i+1]
ll1,ll2 = llt1[:2],llt2[:2]
if len(ret) > 0 and findjustone:
return ret
overall_min_dist = min( overall_min_dist,
gis.distance_from_segment_meters(ll1,ll2,stoploc))
intersect = gis.distance_intersect( ll1,ll2,stoploc,tol )
if intersect is None:
if in_range:
ret.append(current_interval)
in_range = False
current_interval = None
else:
pass
else: # intersect is not None
enter_frac,exit_frac,min_dist = intersect
enter_time = gis.timefrac_helper( llt1[2],llt2[2],enter_frac )
exit_time = gis.timefrac_helper( llt1[2],llt2[2],exit_frac )
if not in_range: # just entered range of stoploc
if exit_frac == 1.0:
current_interval = [ enter_time, exit_time, min_dist ]
in_range = True
else:
ret.append([ enter_time, exit_time, min_dist ])
else: # in_range
if enter_frac != 0.0:
raise Exception, "While in range, found enter_frac of %f" % (enter_frac,)
else:
current_interval[1] = exit_time
current_interval[2] = min(current_interval[2],min_dist)
if exit_frac == 1.0: # we're still in range
pass
else:
ret.append( current_interval )
in_range = False
current_interval = None
else: # end "for i in range..."
if in_range:
ret.append(current_interval)
if not ret: # empty list
print "--- No arrival, min dist was:",overall_min_dist
return ret
def getTimesAtLocation(self,
stoploc,
tol=10.0,
starttime=None,
findjustone=False):
"""
Given a (lat,lon), returns a list of (begin,end,dist) intervals of the
(estimated) times that the bus was within tol meters of that
location, starting at starttime. The 'dist' part of each interval
indicates the estimated minimum distance of the bus from stoploc during
that interval.
If starttime is None, then defaults to the beginning of the track.
If findjustone is True, returns after finding the first complete interval.
"""
in_range = False
current_interval = None # will be [begin,end,dist] holder
ret = []
if starttime is None: starttime = self.min_time
starttime = max(starttime, self.min_time)
if starttime > self.max_time:
return ret
## Process intersection at first sub-segment
startloc = self.getLocationAtTime(starttime)
ll1 = startloc
ll2 = self.interpolation[self.cached_index + 1][:2]
t1, t2 = starttime, self.interpolation[self.cached_index + 1][2]
overall_min_dist = gis.distance_from_segment_meters(ll1, ll2, stoploc)
intersect = gis.distance_intersect(ll1, ll2, stoploc, tol)
if intersect:
enter_frac, exit_frac, min_dist = intersect
enter_time = gis.timefrac_helper(t1, t2, enter_frac)
exit_time = gis.timefrac_helper(t1, t2, exit_frac)
if exit_frac == 1.0:
current_interval = [enter_time, exit_time, min_dist]
in_range = True
else:
ret.append([enter_time, exit_time, min_dist])
## Process subsequent segments
for i in range(self.cached_index + 1, len(self.interpolation) - 1):
llt1 = self.interpolation[i]
llt2 = self.interpolation[i + 1]
ll1, ll2 = llt1[:2], llt2[:2]
if len(ret) > 0 and findjustone:
return ret
overall_min_dist = min(
overall_min_dist,
gis.distance_from_segment_meters(ll1, ll2, stoploc))
intersect = gis.distance_intersect(ll1, ll2, stoploc, tol)
if intersect is None:
if in_range:
ret.append(current_interval)
in_range = False
current_interval = None
else:
pass
else: # intersect is not None
enter_frac, exit_frac, min_dist = intersect
enter_time = gis.timefrac_helper(llt1[2], llt2[2], enter_frac)
exit_time = gis.timefrac_helper(llt1[2], llt2[2], exit_frac)
if not in_range: # just entered range of stoploc
if exit_frac == 1.0:
current_interval = [enter_time, exit_time, min_dist]
in_range = True
else:
ret.append([enter_time, exit_time, min_dist])
else: # in_range
if enter_frac != 0.0:
raise Exception, "While in range, found enter_frac of %f" % (
enter_frac, )
else:
current_interval[1] = exit_time
current_interval[2] = min(current_interval[2],
min_dist)
if exit_frac == 1.0: # we're still in range
pass
else:
ret.append(current_interval)
in_range = False
current_interval = None
else: # end "for i in range..."
if in_range:
ret.append(current_interval)
if not ret: # empty list
print "--- No arrival, min dist was:", overall_min_dist
return ret
