class Link:
def __init__(self, geom, speed):
self.line = LineString(geom['coordinates'], srid=4326)
self.line.transform(32611)
self.speed = speed
self.cur_dist = 0
self.total_dist = self.line.length
def move(self, dt):
distance = self.speed * dt
overshot = distance + self.cur_dist - self.total_dist
if overshot > 0:
self.cur_dist = self.total_dist
return float(overshot) / self.speed
else:
self.cur_dist += distance
return 0
def get_position(self):
pt = self.line.interpolate(self.cur_dist)
pt.transform(3857)
return list(pt)
def crossovers(models,path_id,loc_id):
# SET THE SEARCH OFFSET
search_offset = 50
# FIND CROSSOVERS (NON SELF-INSERSECTING)
try:
# GET LINE PATH
line_pathz = models.segments.objects.filter(segment_id=path_id).values_list('line_path', flat=True)
#line path w/out z values
line_path = line_pathz.extra(select={'line_path':'ST_Force_2D(line_path)'}).values_list('line_path',flat=True)
#Get all other line paths with z values.
other_linesz = models.segments.objects.exclude(segment_id=path_id).filter(line_path__intersects=line_path[0])
#Get all other line paths w/out z values
other_lines = other_linesz.extra(select={'line_path':'ST_Force_2D(line_path)'}).values_list('line_path','segment_id')
#Create a GEOS Well Known Binary reader and set up variables
wkb_r = WKBReader()
points1 = []
line_ids = []
#Find points of intersection w/ interpolated z values for given line
# path
for line in other_lines:
l = wkb_r.read(line[0])
crosses = l.intersection(line_pathz[0])
if crosses.geom_type == 'MultiPoint':
for pt in crosses:
points1.append(pt)
line_ids.append(line[1])
else:
points1.append(crosses)
line_ids.append(line[1])
#Find points of intersection w/ interpolated z values for other line
# paths
points2 = other_linesz.intersection(line_path[0]).values_list('intersection',flat=True)
#EXTRACT x/y coordinates of intersections and gps_time1/2
x=[]
y=[]
gps_time1 = []
gps_time2 = []
#Check all point objects for multiple crossovers and extract x/y coords
# and gps times
for po in points1:
if po.geom_type == 'MultiPoint':
for p in po:
x.append(p[0])
y.append(p[1])
gps_time1.append(p[2])
else:
x.append(po[0])
y.append(po[1])
gps_time1.append(po[2])
for po in points2:
if po.geom_type == 'MultiPoint':
for p in po:
gps_time2.append(p[2])
else:
gps_time2.append(po[2])
#Create point objects for all crossover points
cross_pts = [Point(point) for point in zip(x,y)]
except:
return error_check(sys)
#Find all non-self-intersecting Crossover angles:
try:
#Get the lines associated w/ crossover points
lines = models.segments.objects.filter(segment_id__in=list(set(line_ids))).values_list('line_path','segment_id')
line_dict = {}
for line in lines:
line_dict[line[1]] = line[0]
#Enumerate over line_ids in order to query for the nearest point paths to each cross point.
angles = []
for idx,pt_id in enumerate(line_ids):
try:
#Get the nearest point paths for the other line to the crossover
# point and sort them by point_path_id
line_pts = models.point_paths.objects.filter(segment_id=pt_id, gps_time__range=(repr(gps_time2[idx]-search_offset),repr(gps_time2[idx]+search_offset))).distance(cross_pts[idx]).order_by('distance','gps_time').values_list('point_path','point_path_id','gps_time', 'distance')
line_pts = sorted(line_pts,key=lambda l_id: l_id[1])
#Find the two points adjacent to the cross point. Use time_diff to ensure they are
# the closest two points.
time_diff = None
for pt_idx in range(len(line_pts) - 1):
if float(line_pts[pt_idx][2]) < gps_time2[idx] and float(line_pts[pt_idx+1][2]) > gps_time2[idx]:
if time_diff is None:
time_diff = float(line_pts[pt_idx+1][2])-float(line_pts[pt_idx][2])
change_x1 = line_pts[pt_idx][0].coords[0]-line_pts[pt_idx+1][0].coords[0]
change_y1 = line_pts[pt_idx][0].coords[1]-line_pts[pt_idx+1][0].coords[1]
elif float(line_pts[pt_idx+1][2])-float(line_pts[pt_idx][2]) < time_diff:
time_diff = float(line_pts[pt_idx+1][2])-float(line_pts[pt_idx][2])
change_x1 = line_pts[pt_idx][0].coords[0]-line_pts[pt_idx+1][0].coords[0]
change_y1 = line_pts[pt_idx][0].coords[1]-line_pts[pt_idx+1][0].coords[1]
#Get the nearest point paths for the given line to the crossover
# point and sort them by point_path_id.
line_pts = models.point_paths.objects.filter(segment_id=path_id, gps_time__range=(repr(gps_time1[idx]-search_offset),repr(gps_time1[idx]+search_offset))).distance(cross_pts[idx]).order_by('distance','gps_time').values_list('point_path','point_path_id','gps_time','distance')
line_pts = sorted(line_pts,key=lambda l_id: l_id[1])
time_diff = None
for pt_idx in range(len(line_pts) - 1):
if float(line_pts[pt_idx][2]) < gps_time1[idx] and float(line_pts[pt_idx+1][2]) > gps_time1[idx]:
if time_diff is None:
time_diff = float(line_pts[pt_idx+1][2])-float(line_pts[pt_idx][2])
change_x2 = line_pts[pt_idx][0].coords[0]-line_pts[pt_idx+1][0].coords[0]
change_y2 = line_pts[pt_idx][0].coords[1]-line_pts[pt_idx+1][0].coords[1]
elif float(line_pts[pt_idx+1][2])-float(line_pts[pt_idx][2]) < time_diff:
time_diff = float(line_pts[pt_idx+1][2])-float(line_pts[pt_idx][2])
change_x2 = line_pts[pt_idx][0].coords[0]-line_pts[pt_idx+1][0].coords[0]
change_y2 = line_pts[pt_idx][0].coords[1]-line_pts[pt_idx+1][0].coords[1]
except:
return error_check(sys)
#Check if either of the lines is parallel to the y-axis and find
# the angle of intersection.
if change_x1 == 0 and change_x2 == 0:
angle = 180
elif change_x1 == 0:
angle = degrees(atan(fabs(1/(change_y2/change_x2))))
elif change_x2 == 0:
angle = degrees(atan(fabs(1/(change_y1/change_x1))))
else:
slope1 = change_y1/change_x1
slope2 = change_y2/change_x2
if slope1*slope2 == -1:
angle = 90
else:
angle = degrees(atan(fabs((slope1 - slope2)/(1 + slope1 * slope2))))
#Save all the angles for later
angles.append(angle)
except:
return error_check(sys)
#FIND all self-intersecting crossovers
try:
#Fetch the given line path from the db as a multilinestring.
# 'ST_UnaryUnion' results in a multilinestring with the last point of
# every linestring except the last linestring is a crossover and the
# first point of every linestring except the first linestring is a
# crossover.
line = models.segments.objects.filter(segment_id=path_id).extra(select={'multi_line_path':'ST_UnaryUnion(line_path)'}
).values_list('multi_line_path', flat=True)
#Create a GEOS MultiLineString from the multilinestring fetched above.
lines = wkb_r.read(line[0])
#Check if resulting object is a multilinestring, indicating crossovers.
if lines.geom_type.encode('ascii', 'ignore') == 'MultiLineString':
self_cross = True
#Loop through all linestrings created by ST_UnaryUnion to get crossover
# points and interpolate GPS times.
crossover_gps = {}
crossover_slopes = {}
for idx in range(len(lines) - 1):
#Check if current linestring is composed only of crossovers.
if len(lines[idx].coords) ==2 and idx != 0:
#Fall back on the next linestring not made exclusively of
# crossovers in order to get a good GPS time.
idx1 = idx-1
while idx1 >= 0:
if idx1 == 0 or len(lines[idx1].coords) > 2:
#Check if next linestring is made only of crossovers
# in order to obtain the next linestring w/ good GPS
# time.
if len(lines[idx+1].coords) == 2 and idx+1 != len(lines)-1:
idx2 = idx+2
while idx2 < len(lines):
if idx2 == len(lines)-1 or len(lines[idx2].coords) > 2:
point1 = Point(lines[idx1].coords[-2])
point2 = Point(lines[idx2].coords[1])
#Break while loop
break
else:
idx2 += 1
else:
point1 = Point(lines[idx1].coords[-2])
point2 = Point(lines[idx+1].coords[1])
#Break while loop
break
else:
idx1 = idx1 - 1
#If current linestring is not made exclusively of crossovers, check
# if next one is.
elif len(lines[idx+1].coords) == 2 and idx+1 != len(lines)-1:
idx2 = idx+2
while idx2 < len(lines):
if idx2 == len(lines)-1 or len(lines[idx2].coords) > 2:
point1 = Point(lines[idx].coords[-2])
point2 = Point(lines[idx2].coords[1])
#break loop
break
else:
idx2 += 1
else:
point1 = Point(lines[idx].coords[-2])
point2 = Point(lines[idx+1].coords[1])
#Find the change in x/y in order to determine slope
change_x = point1[0] - point2[0]
change_y = point1[1] - point2[1]
#Check if the change in x is zero
if change_x == 0:
slope = None
else:
slope = change_y/change_x
#Create a new line object from the two points adjacent to the
# crossover.
newline = LineString(point1,point2)
#Find the crossover point/interpolate the gps time.
crossover = Point(lines[idx].coords[-1])
cross_pt = newline.interpolate(newline.project(crossover))
#Use crossover coordinates as keys for a dictionary storing gps
# times
if (crossover[0],crossover[1]) not in crossover_gps.keys():
crossover_gps[crossover[0],crossover[1]] = [cross_pt[2]]
else:
crossover_gps[crossover[0],crossover[1]].append(cross_pt[2])
#Use crossover coordinates as keys for a dictionary storing slopes
if (crossover[0],crossover[1]) not in crossover_slopes.keys():
crossover_slopes[crossover[0], crossover[1]] = [slope]
else:
crossover_slopes[crossover[0], crossover[1]].append(slope)
#Create a dictionary holding both gps times and slopes.
crossovers = crossover_gps
for key in crossover_slopes:
crossovers[key].append(crossover_slopes[key][0])
crossovers[key].append(crossover_slopes[key][1])
del crossover_gps, crossover_slopes
#Extract self-intersecting crossovers information from above.
self_cross_pts = []
self_gps1 = []
self_gps2 = []
self_angles = []
for x,y in crossovers:
self_cross_pts.append(Point(x,y))
self_gps1.append(crossovers[x,y][0])
self_gps2.append(crossovers[x,y][1])
#Determine angle of intersection
slope1 = crossovers[x,y][2]
slope2 = crossovers[x,y][3]
if slope1 == None and slope2 == None:
angle = 180
elif slope1 == None:
angle = degrees(atan(fabs(1/slope2)))
elif slope2 == None:
angle = degrees(atan(fabs(1/slope1)))
else:
if slope1*slope2 == -1:
angle = 90
else:
angle = degrees(atan(fabs((slope1 - slope2)/
(1 + slope1 * slope2))))
self_angles.append(angle)
else:
self_cross = False
except:
return error_check(sys)
#Format and return crossovers for writing to CSV file:
try:
rows = []
#Non-self-intersecting crossovers
for idx, pt in enumerate(cross_pts):
rows.append([path_id,line_ids[idx],repr(gps_time1[idx]), repr(gps_time2[idx]), repr(angles[idx]), repr(pt[0]), repr(pt[1]), loc_id])
if self_cross:
#Self-intersecting crossovers
for idx, pt in enumerate(self_cross_pts):
rows.append([path_id,path_id,repr(self_gps1[idx]),repr(self_gps2[idx]),repr(self_angles[idx]),repr(pt[0]),repr(pt[1]),loc_id])
return rows
except:
return error_check(sys)
