Update main.py

main.py

@@ -12,6 +12,9 @@ app = FastAPI(title="GeoJSON and Heatmap API", description="API for random coord
 # Global variable to store the last selected coordinate
 last_coordinate: List[float] = None
 
+# Polygon bounds for Singrauli
+POLYGON_BOUNDS = [(82.5065, 22.3105), (82.628, 22.3105), (82.628, 22.3421), (82.5065, 22.3421)]
+
 # Load GeoJSON data from file
 def load_geojson_data(file_path: str = "synthetic_ps_points.geojson") -> Dict[str, Any]:
     try:
@@ -35,6 +38,19 @@ def load_csv_data(file_path: str = "synthetic_ps_points.csv") -> pd.DataFrame:
 def calculate_distance(coord1: List[float], coord2: List[float]) -> float:
     return math.sqrt((coord2[0] - coord1[0]) ** 2 + (coord2[1] - coord1[1]) ** 2)
 
+# Point-in-polygon check using ray-casting algorithm
+def is_point_in_polygon(point: List[float], polygon: List[tuple]) -> bool:
+    x, y = point[0], point[1]
+    n = len(polygon)
+    inside = False
+    j = n - 1
+    for i in range(n):
+        if ((polygon[i][1] > y) != (polygon[j][1] > y)) and \
+           (x < (polygon[j][0] - polygon[i][0]) * (y - polygon[i][1]) / (polygon[j][1] - polygon[i][1]) + polygon[i][0]):
+            inside = not inside
+        j = i
+    return inside
+
 # Find the closest feature to a given coordinate
 def find_closest_feature(coord: List[float], features: List[Dict]) -> Dict:
     min_distance = float('inf')
@@ -57,14 +73,14 @@ def generate_path(start_coord: List[float], end_coord: List[float], num_steps: i
         path.append({"step": i, "coordinates": [lon, lat]})
     return path
 
-# Endpoint to get a single random coordinate, ensuring separation from the last coordinate
+# Endpoint to get a single random coordinate, ensuring wide separation from the last coordinate
 @app.get("/get-coordinates", response_model=dict)
-async def get_random_coordinates(min_distance: float = 0.01):
+async def get_random_coordinates(min_distance: float = 0.05):
     """
-    Returns a single random coordinate with associated properties, ensuring a minimum distance from the last selected coordinate.
+    Returns a single random coordinate within the Singrauli polygon, ensuring a minimum distance from the last selected coordinate.
     
     Parameters:
-    - min_distance: Minimum distance from the last coordinate in degrees (default: 0.01)
+    - min_distance: Minimum distance from the last coordinate in degrees (default: 0.05, ~5.5 km)
     """
     global last_coordinate
     data = load_geojson_data()
@@ -72,12 +88,17 @@ async def get_random_coordinates(min_distance: float = 0.01):
     if not features:
         raise HTTPException(status_code=400, detail="No features found in GeoJSON data")
     
+    # Filter features within the Singrauli polygon
+    valid_features = [f for f in features if is_point_in_polygon(f["geometry"]["coordinates"], POLYGON_BOUNDS)]
+    if not valid_features:
+        raise HTTPException(status_code=400, detail="No features found within the Singrauli polygon")
+    
     selected_feature = None
     attempts = 0
-    max_attempts = 100  # Prevent infinite loops
+    max_attempts = 200  # Increased to handle sparse valid selections
     
     while attempts < max_attempts:
-        random_feature = random.choice(features)
+        random_feature = random.choice(valid_features)
         random_coord = random_feature["geometry"]["coordinates"]
         
         # Check distance from last coordinate (if it exists)
@@ -197,7 +218,7 @@ async def root():
     return {
         "message": "Welcome to the GeoJSON and Heatmap API",
         "endpoints": {
-            "/get-coordinates": "Returns a single random coordinate with associated properties, ensuring separation from the last coordinate",
+            "/get-coordinates": "Returns a single random coordinate within the Singrauli polygon, widely spaced from the last coordinate",
             "/simulate-worker-path": "Simulates a worker's path from a normal risk to a high risk zone",
             "/heatmap": "Returns raw HTML for a Folium heatmap of PS data"
         }