GPS-Logger/workers/points2trips.py

import json
import gzip
import random
from datetime import datetime, timedelta
import colorsys
from math import radians, cos, sin, asin, sqrt

from django.contrib.gis.geos import Point, LineString


from ..models import Marker, Trip


max_time_diff = timedelta(hours=6)
max_distance = 3000 # m

class TripConverter:
  trips: list[Trip]

  def __init__(self, markers: list[Marker]):
    self.trips = []
    first_index = 0
    for i, point in enumerate(markers[1:]):
      prev_point = markers[i-1]
      if point.timestamp - prev_point.timestamp > max_time_diff or \
          Distance(point.location, prev_point.location) > max_distance:
        if i - first_index > 2:
          self.trips.append(create_trip(markers[first_index:i]))
        first_index = i
    
    if first_index < len(markers) - 2:
      self.trips.append(create_trip(markers[first_index:]))

  def save(self):
    for trip in self.trips:
      trip.save()

def create_trip(markers: list[Marker]) -> Trip:
  print(len(markers), markers[0].timestamp, markers[-1].timestamp)
  trip = Trip.objects.filter(startTime__lte=markers[-1].timestamp, endTime__gte=markers[0].timestamp).first()
  if not trip:
    trip = Trip.objects.create(
      startTime = markers[0].timestamp,
      endTime = markers[-1].timestamp,
      name = f"Trip {markers[0].timestamp}",
      color = get_path_color(markers[0].timestamp)
    )
  elif trip.startTime == markers[0].timestamp and trip.endTime == markers[-1].timestamp:
    data = json.loads(gzip.decompress(trip.path))
    if len(data) > len(markers) * 0.9 and len(data) <= len(markers):
      print("Trip already exists")
      return trip

  trip.startTime = markers[0].timestamp
  trip.endTime = markers[-1].timestamp
  trip.totalTime = trip.endTime - trip.startTime
  center = markers[len(markers)//2].location
  trip.center = Point(center.x, center.y)

  total_distance = 0 # m
  topSpeed = 0 # km/h
  ascendHeight = 0 # m
  descendHeight = 0 # m
  movementTime = timedelta(0)

  minLat = minLon = maxLat = maxLon = None

  lastSpeed = 0
  i = 1

  while i < len(markers):
    point = markers[i]
    prev_point = markers[i-1]
    dist = Distance(point.location, prev_point.location)
    if point.speed is not None and point.speed > 0:
      speed = point.speed
    else:
      speed = dist / abs(point.timestamp - prev_point.timestamp).seconds * 3.6

    if abs(speed - lastSpeed) / abs(point.timestamp - prev_point.timestamp).seconds > 10: # m/s²
      markers.remove(point)
      continue

    if abs(speed - lastSpeed) > 50: # m/s
      markers.remove(point)
      continue

    total_distance += dist
    topSpeed = max(topSpeed, speed)

    minLat = min(minLat, point.location.y) if minLat is not None else point.location.y
    minLon = min(minLon, point.location.x) if minLon is not None else point.location.x
    maxLat = max(maxLat, point.location.y) if maxLat is not None else point.location.y
    maxLon = max(maxLon, point.location.x) if maxLon is not None else point.location.x
    
    if speed > 2.0: # km/h
      movementTime += abs(point.timestamp - prev_point.timestamp)

    if point.alt is not None and prev_point.alt is not None:
      if point.alt > prev_point.alt:
        ascendHeight += point.alt - prev_point.alt
      else:
        descendHeight += prev_point.alt - point.alt
    i += 1

  trip.distance = round(total_distance, 1) # m
  trip.topSpeed = round(topSpeed, 1) # km/h
  trip.avgSpeed = round(total_distance / (movementTime or trip.endTime - trip.startTime).total_seconds() * 3.6, 1) # km/h
  trip.ascendHeight = round(ascendHeight, 1) # m
  trip.descendHeight = round(descendHeight, 1) # m
  trip.movementTime = movementTime

  trip.line = LineString((markers[0].location.x, markers[0].location.y), (markers[-1].location.x, markers[-1].location.y))

  trip.path = points_to_blob(markers)

  return trip

def Distance(point1: Point, point2: Point) -> float:
  lon1 = radians(point1.x)
  lon2 = radians(point2.x)
  lat1 = radians(point1.y)
  lat2 = radians(point2.y)
  
  # Haversine formula 
  dlon = lon2 - lon1 
  dlat = lat2 - lat1 
  a = sin(dlat/2)**2 + cos(lat1) * cos(lat2) * sin(dlon/2)**2
  c = 2 * asin(sqrt(a)) 
  r = 6371000 # Radius of earth in meters. Use 3956 for miles
  return c * r

def get_path_color(time: datetime) -> str:
  random.seed(int(time.timestamp()))
  hue = random.random()
  saturation = 0.5 + random.random() / 2
  value = 0.5 + random.random() / 2
  rgb = colorsys.hsv_to_rgb(hue, saturation, value)
  return f"#{int(rgb[0]*255):02x}{int(rgb[1]*255):02x}{int(rgb[2]*255):02x}"

def convert_points_to_trips():
  points = list(Marker.objects.all())
  converter = TripConverter(points)
  converter.save()

def points_to_blob(markers) -> bytes:
  arr = []

  for marker in markers:
    arr.append({
      "lat": marker.location.y,
      "lng": marker.location.x,
      "alt": marker.alt,
      "hdop": marker.hdop,
      "speed": marker.speed,
      "timestamp": marker.timestamp.timestamp(),
    })
  data = json.dumps(arr).encode('utf-8')
  return gzip.compress(data)