normalising polygons has more control on starting point and orientati…

…on (#117)

* normalising polygons has more control on starting point and orientation

* missing import

* isort

detectree2/models/outputs.py

@@ -19,7 +19,7 @@
 import rasterio
 from rasterio.crs import CRS
 from shapely.geometry import Polygon, box, shape
-from shapely.ops import unary_union
+from shapely.ops import orient, unary_union
 
 
 def polygon_from_mask(masked_arr):
@@ -405,11 +405,34 @@ def load_geopandas_dataframes(folder):
 
 
 # Function to normalize and average polygons, considering weights
+#def normalize_polygon(polygon, num_points):
+#    total_perimeter = polygon.length
+#    distance_between_points = total_perimeter / num_points
+#    points = [polygon.boundary.interpolate(i * distance_between_points) for i in range(num_points)]
+#    return Polygon(points)
+
 def normalize_polygon(polygon, num_points):
+    # Orient polygon to ensure consistent vertex order (counterclockwise)
+    polygon = orient(polygon, sign=1.0)
+
+    # Get all points
+    points = list(polygon.exterior.coords)
+
+    # Get point with minimum average of x and y
+    min_avg_point = min(points, key=lambda point: sum(point)/len(point))
+
+    # Rotate points to start from min_avg_point
+    min_avg_point_idx = points.index(min_avg_point)
+    points = points[min_avg_point_idx:] + points[:min_avg_point_idx]
+
+    # Create a new polygon with ordered points
+    polygon = Polygon(points)
+
     total_perimeter = polygon.length
     distance_between_points = total_perimeter / num_points
-    points = [polygon.boundary.interpolate(i * distance_between_points) for i in range(num_points)]
-    return Polygon(points)
+
+    normalized_points = [polygon.boundary.interpolate(i * distance_between_points) for i in range(num_points)]
+    return Polygon(normalized_points)
 
 
 def average_polygons(polygons, weights=None, num_points=300):