snow_rendering

Turn weather data into driving safety guidance. snow_rendering classifies road surface conditions, computes grip factors, and derives visibility and precipitation parameters from real weather observations.

Pure Dart — no Flutter dependency. Safe to use from any Dart environment.

Features

• RoadSurfaceState — six-state classification (dry, wet, slush, compactedSnow, blackIce, standingWater) with grip factors
• DrivingConditionAssessment — combined assessment with advisory message from a single WeatherCondition
• PrecipitationConfig — particle count, velocity, size, and lifetime parameters by type and intensity
• VisibilityDegradation — opacity and blur sigma from visibility distance in metres
• HysteresisFilter<T> — debounce filter preventing rapid oscillation at boundary conditions

Install

dependencies:
  snow_rendering: ^0.1.0

Quick Start

import 'package:driving_weather/driving_weather.dart';
import 'package:snow_rendering/snow_rendering.dart';

final condition = WeatherCondition(
  precipType: PrecipitationType.snow,
  intensity: PrecipitationIntensity.heavy,
  temperatureCelsius: -5,
  visibilityMeters: 400,
  windSpeedKmh: 30,
  iceRisk: false,
  timestamp: DateTime.now(),
);

final assessment = DrivingConditionAssessment.fromCondition(condition);
print(assessment.surfaceState);    // RoadSurfaceState.compactedSnow
print(assessment.gripFactor);      // 0.3
print(assessment.advisoryMessage); // Compacted snow — use winter tyres, reduce speed
print(assessment.visibility.blurSigma); // 2.0 (mild blur at 400m)
print(assessment.precipitation.particleCount); // 500 (heavy snow)

Debounced Classification

Wrap in HysteresisFilter to prevent flickering at boundary conditions:

final filter = HysteresisFilter<RoadSurfaceState>();
// Requires the same state in 2 of last 3 readings before transitioning.
final stable = filter.update(RoadSurfaceState.fromCondition(condition));

Road Surface States