def _expand_address(self, addr, roadnet, length='length' ) :
# only ever done at the beginning!!
options = []
# find the interval containing addr
roadtree = self.get_roadtree( addr.road )
_, floor_addr = roadtree.floor_item( addr.coord )
_, ceil_addr = roadtree.ceiling_item( addr.coord )
# obtain relevant road data for addr.road
u, v, roadlen = roadinfo( addr.road, roadnet )
# look left
if floor_addr is None :
left_boundary = ROAD.RoadAddress( addr.road, 0. )
options.append( ( u, left_boundary ) )
elif my_isaddress( floor_addr ) :
options.append( ( floor_addr, floor_addr ) )
else :
raise 'invalid node type'
# look right
if ceil_addr is None :
right_boundary = ROAD.RoadAddress( addr.road, roadlen )
options.append( ( v, right_boundary ) )
elif my_isaddress( ceil_addr ) :
options.append( ( ceil_addr, ceil_addr ) )
else :
raise 'invalid node type'
res = []
for ( targ, targ_addr ) in options :
traveltime = ROAD.distance( roadnet, addr, targ_addr, length )
res.append( ( targ, traveltime ) )
return res
def find_nearest( addr ) :
dist_to = lambda q : ROAD.distance( roadnet, addr, q, 'length' )
trips = [ ( dist_to(q), q ) for q in points ]
return min( trips )[1]
points = [ roadprob.sampleaddress( roadnet ) for i in range(n) ]
pset = PointSet()
for p in points :
pset.insert( p )
def find_nearest( addr ) :
dist_to = lambda q : ROAD.distance( roadnet, addr, q, 'length' )
trips = [ ( dist_to(q), q ) for q in points ]
return min( trips )[1]
def sidebyside( addr ) :
by_pset = pset.find_nearest( addr, roadnet )
by_naive = find_nearest( addr )
return by_pset, by_naive
samples = 100
testpoints = [ roadprob.sampleaddress( roadnet ) for i in range(samples) ]
answers = [ sidebyside( q ) for q in testpoints ]
error = [ ROAD.distance( roadnet, p, q, 'length' ) for p, q in answers ]
