Using the Chapters Map

import requests
from math import radians, sin, cos, sqrt, atan2

def haversine_distance(lat1, lon1, lat2, lon2):
    """Calculate distance between two points in kilometers."""
    R = 6371  # Earth's radius in km
    
    dlat = radians(lat2 - lat1)
    dlon = radians(lon2 - lon1)
    a = sin(dlat/2)**2 + cos(radians(lat1)) * cos(radians(lat2)) * sin(dlon/2)**2
    c = 2 * atan2(sqrt(a), sqrt(1-a))
    
    return R * c

def find_nearby_chapters(my_lat, my_lon, max_distance_km=100):
    # Get all chapters
    response = requests.get("https://nest.owasp.org/api/v0/chapters/")
    chapters = response.json()["results"]
    
    # Filter by distance
    nearby = []
    for chapter in chapters:
        if chapter["latitude"] and chapter["longitude"]:
            distance = haversine_distance(
                my_lat, my_lon,
                chapter["latitude"], chapter["longitude"]
            )
            if distance <= max_distance_km:
                chapter["distance_km"] = round(distance, 2)
                nearby.append(chapter)
    
    # Sort by distance
    nearby.sort(key=lambda x: x["distance_km"])
    return nearby

# Find chapters within 100km of London
nearby_chapters = find_nearby_chapters(51.5074, -0.1278, 100)