334 lines
10 KiB
Python
334 lines
10 KiB
Python
"""Open-Meteo historical weather client + simple road-risk heuristics.
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Backwards-compatible API:
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- fetch_weather(lat, lon, params=None, api_key=None)
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- fetch_road_risk(lat, lon, extra_params=None, api_key=None, roadrisk_url=None)
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- get_risk_score(lat, lon, **fetch_kwargs)
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- compute_reroute(...)
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- compute_index_and_reroute(...)
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"""
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import os
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from typing import Tuple, Dict, Any, Optional, Callable, List
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import requests
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import heapq
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import math
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from datetime import date, timedelta
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# Open-Meteo archive endpoint (no API key required)
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BASE_ARCHIVE_URL = "https://archive-api.open-meteo.com/v1/archive"
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def fetch_weather(lat: float, lon: float, params: Optional[dict] = None, api_key: Optional[str] = None) -> dict:
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"""Fetch historical weather from Open-Meteo archive API.
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Params may include 'start_date', 'end_date' (YYYY-MM-DD) and 'hourly' (comma-separated vars).
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Defaults to yesterday..today and hourly variables useful for road risk.
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(api_key parameter is accepted for compatibility but ignored.)
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"""
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if params is None:
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params = {}
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today = date.today()
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start = params.get("start_date", (today - timedelta(days=1)).isoformat())
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end = params.get("end_date", today.isoformat())
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hourly = params.get(
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"hourly",
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",".join(["temperature_2m", "relativehumidity_2m", "windspeed_10m", "precipitation", "weathercode"])
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)
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query = {
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"latitude": lat,
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"longitude": lon,
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"start_date": start,
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"end_date": end,
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"hourly": hourly,
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"timezone": params.get("timezone", "UTC"),
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}
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resp = requests.get(BASE_ARCHIVE_URL, params=query, timeout=15)
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resp.raise_for_status()
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return resp.json()
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def fetch_road_risk(
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lat: float,
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lon: float,
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extra_params: Optional[dict] = None,
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api_key: Optional[str] = None,
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roadrisk_url: Optional[str] = None
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) -> Tuple[dict, Dict[str, Any]]:
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"""
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Compute a simple road risk estimation using Open-Meteo historical weather.
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Returns (raw_data, features) where features includes 'road_risk_score' (float).
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api_key and roadrisk_url are accepted for backward compatibility but ignored.
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"""
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params = {}
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if extra_params:
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params.update(extra_params)
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# fetch weather via Open-Meteo archive
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try:
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data = fetch_weather(lat, lon, params=params)
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except Exception as e:
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features: Dict[str, Any] = {"road_risk_score": 0.0, "error": str(e)}
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return {}, features
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hourly = data.get("hourly", {}) if isinstance(data, dict) else {}
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def _arr_mean(key):
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arr = hourly.get(key)
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if isinstance(arr, list) and arr:
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valid = [float(x) for x in arr if x is not None]
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return sum(valid) / max(1, len(valid)) if valid else None
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return None
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def _arr_max(key):
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arr = hourly.get(key)
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if isinstance(arr, list) and arr:
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valid = [float(x) for x in arr if x is not None]
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return max(valid) if valid else None
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return None
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precip_mean = _arr_mean("precipitation")
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wind_mean = _arr_mean("windspeed_10m")
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wind_max = _arr_max("windspeed_10m")
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temp_mean = _arr_mean("temperature_2m")
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humidity_mean = _arr_mean("relativehumidity_2m")
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weathercodes = hourly.get("weathercode", [])
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# heuristic risk scoring:
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risk = 0.0
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if precip_mean is not None:
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risk += float(precip_mean) * 2.0
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if wind_mean is not None:
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risk += float(wind_mean) * 0.1
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if wind_max is not None and float(wind_max) > 15.0:
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risk += 1.0
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if humidity_mean is not None and float(humidity_mean) > 85.0:
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risk += 0.5
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try:
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# sample Open-Meteo weather codes that indicate precipitation/snow
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if any(int(wc) in (51, 61, 63, 65, 80, 81, 82, 71, 73, 75, 85, 86) for wc in weathercodes if wc is not None):
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risk += 1.0
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except Exception:
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pass
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if not math.isfinite(risk):
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risk = 0.0
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if risk < 0:
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risk = 0.0
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features: Dict[str, Any] = {
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"precipitation_mean": float(precip_mean) if precip_mean is not None else None,
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"wind_mean": float(wind_mean) if wind_mean is not None else None,
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"wind_max": float(wind_max) if wind_max is not None else None,
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"temp_mean": float(temp_mean) if temp_mean is not None else None,
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"humidity_mean": float(humidity_mean) if humidity_mean is not None else None,
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"road_risk_score": float(risk),
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}
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# include some raw metadata if present
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if "latitude" in data:
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features["latitude"] = data.get("latitude")
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if "longitude" in data:
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features["longitude"] = data.get("longitude")
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if "generationtime_ms" in data:
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features["generationtime_ms"] = data.get("generationtime_ms")
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return data, features
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def _haversine_km(a_lat: float, a_lon: float, b_lat: float, b_lon: float) -> float:
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# returns distance in kilometers
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R = 6371.0
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lat1, lon1, lat2, lon2 = map(math.radians, (a_lat, a_lon, b_lat, b_lon))
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dlat = lat2 - lat1
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dlon = lon2 - lon1
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h = math.sin(dlat / 2) ** 2 + math.cos(lat1) * math.cos(lat2) * math.sin(dlon / 2) ** 2
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return 2 * R * math.asin(min(1.0, math.sqrt(h)))
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def risk_to_index(risk_score: float, max_risk: float = 10.0, num_bins: int = 10) -> int:
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"""
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Map a numeric risk_score to an integer index 1..num_bins (higher => more risky).
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"""
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if risk_score is None:
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return 1
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r = float(risk_score)
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if r <= 0:
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return 1
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if r >= max_risk:
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return num_bins
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bin_width = max_risk / float(num_bins)
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return int(r // bin_width) + 1
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def get_risk_score(lat: float, lon: float, **fetch_kwargs) -> float:
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"""Wrapper: calls fetch_road_risk and returns features['road_risk_score'] (float)."""
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_, features = fetch_road_risk(lat, lon, extra_params=fetch_kwargs)
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return float(features.get("road_risk_score", 0.0))
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def compute_reroute(
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start_lat: float,
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start_lon: float,
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end_lat: float,
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end_lon: float,
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risk_provider: Callable[[float, float], float] = None,
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n_lat: int = 20,
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n_lon: int = 20,
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distance_weight: float = 0.1,
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max_calls: Optional[int] = None
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) -> Dict[str, Any]:
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"""
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Plan a path from (start_lat, start_lon) to (end_lat, end_lon) that avoids risky areas.
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Uses Dijkstra's algorithm over a lat/lon grid with cost = avg risk + distance_weight * distance.
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"""
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if risk_provider is None:
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risk_provider = lambda lat, lon: get_risk_score(lat, lon)
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min_lat = min(start_lat, end_lat)
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max_lat = max(start_lat, end_lat)
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min_lon = min(start_lon, end_lon)
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max_lon = max(start_lon, end_lon)
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lat_padding = (max_lat - min_lat) * 0.2
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lon_padding = (max_lon - min_lon) * 0.2
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min_lat -= lat_padding
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max_lat += lat_padding
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min_lon -= lon_padding
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max_lon += lon_padding
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lat_step = (max_lat - min_lat) / (n_lat - 1) if n_lat > 1 else 0.0
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lon_step = (max_lon - min_lon) / (n_lon - 1) if n_lon > 1 else 0.0
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coords = []
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for i in range(n_lat):
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for j in range(n_lon):
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coords.append((min_lat + i * lat_step, min_lon + j * lon_step))
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risks = []
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calls = 0
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for lat, lon in coords:
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if max_calls is not None and calls >= max_calls:
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risks.append(float('inf'))
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continue
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try:
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risk = risk_provider(lat, lon)
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except Exception:
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risk = float('inf')
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risks.append(float(risk))
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calls += 1
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def idx(i, j):
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return i * n_lon + j
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def find_closest(lat, lon):
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i = round((lat - min_lat) / (lat_step if lat_step != 0 else 1e-9))
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j = round((lon - min_lon) / (lon_step if lon_step != 0 else 1e-9))
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i = max(0, min(n_lat - 1, i))
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j = max(0, min(n_lon - 1, j))
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return idx(i, j)
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start_idx = find_closest(start_lat, start_lon)
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end_idx = find_closest(end_lat, end_lon)
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N = len(coords)
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dist = [math.inf] * N
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prev = [None] * N
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dist[start_idx] = 0.0
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pq = [(0.0, start_idx)]
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while pq:
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cost, u = heapq.heappop(pq)
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if cost > dist[u]:
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continue
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if u == end_idx:
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break
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ui, uj = u // n_lon, u % n_lon
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for di, dj in ((1, 0), (-1, 0), (0, 1), (0, -1)):
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vi, vj = ui + di, uj + dj
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if 0 <= vi < n_lat and 0 <= vj < n_lon:
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v = idx(vi, vj)
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if math.isinf(risks[v]) or math.isinf(risks[u]):
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continue
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lat_u, lon_u = coords[u]
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lat_v, lon_v = coords[v]
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d_km = _haversine_km(lat_u, lon_u, lat_v, lon_v)
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edge_cost = (risks[u] + risks[v]) / 2 + distance_weight * d_km
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new_cost = cost + edge_cost
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if new_cost < dist[v]:
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dist[v] = new_cost
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prev[v] = u
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heapq.heappush(pq, (new_cost, v))
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if math.isinf(dist[end_idx]):
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return {
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"reroute_needed": False,
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"reason": "no_path_found",
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"start_coord": (start_lat, start_lon),
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"end_coord": (end_lat, end_lon),
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"calls_made": calls
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}
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path_indices = []
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u = end_idx
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while u is not None:
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path_indices.append(u)
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u = prev[u]
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path_indices.reverse()
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path_coords = [coords[i] for i in path_indices]
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return {
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"reroute_needed": True,
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"start_coord": (start_lat, start_lon),
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"end_coord": (end_lat, end_lon),
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"path": path_coords,
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"total_cost": dist[end_idx],
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"start_risk": risks[start_idx],
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"end_risk": risks[end_idx],
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"calls_made": calls,
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"grid_shape": (n_lat, n_lon)
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}
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def compute_index(lat: float,
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lon: float,
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max_risk: float = 10.0,
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num_bins: int = 10,
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risk_provider: Optional[Callable[[float, float], float]] = None) -> int:
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"""
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Computes and returns an index based on road risk and accident information.
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Args:
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lat: Latitude of the location.
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lon: Longitude of the location.
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max_risk: Maximum possible road risk score.
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num_bins: Number of bins to divide the risk range into.
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reroute_kwargs: Optional dictionary passed to reroute logic.
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risk_provider: Optional custom risk provider function.
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Returns:
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An integer index (1 to num_bins) based on computed road risk.
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"""
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# If a risk provider is not provided, use a default one
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if risk_provider is None:
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risk_provider = lambda lat, lon: get_risk_score(lat, lon)
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# Fetch road risk score using the provided risk provider
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road_risk = float(risk_provider(lat, lon))
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# Compute the index based on road risk score and the max_risk, num_bins parameters
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# The formula will divide the risk score into `num_bins` bins
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# The index will be a number between 1 and num_bins based on the risk score
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# Normalize the risk score to be between 0 and max_risk
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normalized_risk = min(road_risk, max_risk) / max_risk
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# Compute the index based on the normalized risk score
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index = int(normalized_risk * num_bins)
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# Ensure the index is within the expected range of 1 to num_bins
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return max(1, min(index + 1, num_bins)) # Adding 1 because index is 0-based |