update: minor optimalisation

server/map/get_relation.py

@@ -3,12 +3,14 @@ from shapely.geometry import Polygon, Point, LineString, MultiPolygon
 import matplotlib.pyplot as plt
 import matplotlib.ticker as ticker
 import random
+import math
 import numpy as np
 
 polygon_min_x = None  # The left most point of the entire polygon
 
 
-def get_relation(self, body_of_water: str):
+# Read a json file with relation data and send to response object
+def get_relation(self, body_of_water: str):  # NB: implement body_of_water
     # Load GeoJSON data using geopandas
     geo_data = gpd.read_file("server/map/mjosa.geojson")
 
@@ -112,29 +114,8 @@ def cut_polygon_by_points(polygon: Polygon, divisor: float, cell_size: float):
             else:
                 remaining_shape.append(point)
 
-    #################################################################
-        # Prepend new points onto the newly created edge to facilitate vertical splitting
-        if len(split_shape) > 2 and polygon_min_x is not None:
-            # Define starting point with an x-value that will be common for all polygons
-            starting_point = polygon_min_x
-
-            # Get corners of the newly created shape which make up the new edge
-            right_corner = split_shape[-1]
-            left_corner = split_shape[0]
-
-            print("right_corner: ", right_corner, "    left_corner: ", left_corner, "   cell_size: ", cell_size)
-
-            while starting_point < left_corner.x:  # Increment starting point until it is withing the polygons bounds
-                starting_point += cell_size
-
-            # Insert new points with cell_size spacing while starting_point is within bounds
-            while starting_point < right_corner.x:
-
-                split_shape.insert(0, (starting_point, divisor))  # NB may have to add/subtract small offset of 0.00001
-                remaining_shape.insert(0, (starting_point, divisor))  # Prepend new point to shape
-
-                starting_point += cell_size
-    #################################################################
+        # Add points to the newly created edges of split_shape and remaining_shape
+        split_shape, remaining_shape = populate_new_edge(split_shape, remaining_shape, cell_size, divisor)
 
     else:  # Vertical split
         for point in exterior_coords:
@@ -162,6 +143,35 @@ def cut_polygon_by_points(polygon: Polygon, divisor: float, cell_size: float):
     return Polygon(split_shape), Polygon(remaining_shape)
 
 
+# Adds equally spaced points along an edge that is created after a polygon is cut.
+def populate_new_edge(split_shape, remaining_shape, cell_size: float, divisor: float):
+    # Prepend new points onto the newly created edge to facilitate vertical splitting
+    if len(split_shape) > 2 and polygon_min_x is not None:
+        # Define starting point with an x-value that will be common for all polygons
+        starting_point = polygon_min_x
+
+        # Get corners of the newly created shape which make up the new edge
+        right_corner = split_shape[-1]
+        left_corner = split_shape[0]
+
+        print("right_corner: ", right_corner, "    left_corner: ", left_corner, "   cell_size: ", cell_size)
+
+        while starting_point < left_corner.x:  # Increment starting point until it is withing the polygons bounds
+            starting_point += cell_size
+
+        # if starting_point < left_corner.x: # NB: optimised substitute for previous while loop, requires testing
+        #    starting_point += cell_size * math.floor(starting_point - left_corner.x)
+
+        # Insert new points with cell_size spacing while starting_point is within bounds
+        while starting_point < right_corner.x:
+            split_shape.insert(0, (starting_point, divisor))  # NB may have to add/subtract small offset of 0.00001
+            remaining_shape.insert(0, (starting_point, divisor))  # Prepend new point to shape
+
+            starting_point += cell_size
+
+        return split_shape, remaining_shape
+
+
 # Generate grid of equally spaced x and y coordinates where the grid size is determined by cell_size
 def create_grid_coords(polygon: Polygon, cell_size: float):
     # Define boundaries of grid
@@ -174,7 +184,7 @@ def create_grid_coords(polygon: Polygon, cell_size: float):
     x_coords = np.arange(min_x, max_x, cell_size)
     y_coords = np.arange(min_y, max_y, cell_size)
 
-    # Round the coordinates to 4 decimals
+    # Round coordinates to 4 decimals
     x_coords_rounded = np.around(x_coords, decimals=4)
     y_coords_rounded = np.around(y_coords, decimals=4)