Accessibility Analysis API

A FastAPI-based service that analyzes street accessibility using OpenStreetMap data. The system calculates accessibility scores for wheelchair users and their companions based on various street features.

Features

• Accessibility Scoring: Calculates two scores:
  • singular_rate: Accessibility score for wheelchair users alone
  • accompany_rate: Accessibility score for wheelchair users with companions
  • reason: The reason of the lowering of the score, this will allow the final user for further considerations on the route.
• Comprehensive Analysis: Evaluates multiple factors:
  • Street incline (slope)
  • Path width
  • Surface type and quality
  • Presence of barriers and steps
  • Sidewalk availability
  • Curb types

API Endpoints

POST /calculate_accessibility_rate

Calculates accessibility scores for a given location.

Request Body:

{
  "latitude": 41.8986,
  "longitude": 12.4769,
  "other_user_details": "user cannot go on stairs"
}

Response:

{
  "singular_rate": 0,
  "accompany_rate": 0,
  "reason": "Stairs"
}

Score Interpretation:

• 1.0: Perfect accessibility
• 0.0: Complete barrier (impassable)
• Values between: Relative accessibility (higher = better)

Technical Architecture

Components

1. extract_data.py: Fetches OSM data for a given location

   • Queries OpenStreetMap Overpass API
   • Extracts relevant accessibility features
   • Returns structured JSON data

2. calculate_rate.py: Core scoring algorithm

   • Implements accessibility rules and scoring logic
   • Returns Pydantic model with both scores
   • Handles edge cases and blocking conditions

3. endpoint.py: FastAPI server

   • REST API endpoint for accessibility analysis
   • Input validation using Pydantic models
   • Error handling and response formatting

4. test.py: Test client

   • Simple script to test the API
   • Error handling for connection issues

Data Flow

Client → FastAPI → extract_data.py → OSM API
                     ↓
           calculate_rate.py → Scoring Logic
                     ↓
             FastAPI → JSON Response

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/handicapai.git
   cd handicapai

2. Install dependencies:

   pip install -r requirements.txt

3. Run the server:

   uvicorn endpoint:app --reload

4. Test the API:

   python test.py

Usage Examples

Using curl:

curl -X POST http://127.0.0.1:8000/calculate_accessibility_rate \
  -H "Content-Type: application/json" \
  -d '{"latitude": 41.8986, "longitude": 12.4769}'

Using Python requests:

import requests

response = requests.post(
    "http://127.0.0.1:8000/calculate_accessibility_rate",
    json={"latitude": 41.8986, "longitude": 12.4769}
)
result = response.json()
print(f"Wheelchair accessibility: {result['singular_rate']}")
print(f"With companion: {result['accompany_rate']}")

Scoring Methodology

Absolute Blockers (Score = 0.0)

• Presence of steps
• Physical barriers
• Missing sidewalks
• Sand/unpaved surfaces
• Very bad surface quality

Individual Blockers (Only affects singular_rate)

• Raised curbs
• Incline > 3%
• Width < 0.9m

Scoring Factors

• Incline: Linear scoring based on slope percentage
• Width: Different thresholds for solo vs. accompanied travel
• Surface: Quality-based scoring (asphalt = 1.0, sand = 0.0)
• Smoothness: Surface regularity scoring