FastBingTileGenerator for significantly speeding up grid generation

geowrangler/_modidx.py

@@ -109,6 +109,14 @@
                                                                                                                  'geowrangler/distance_zonal_stats.py'),
                                                   'geowrangler.distance_zonal_stats.create_distance_zonal_stats': ( 'distance_zonal_stats.html#create_distance_zonal_stats',
                                                                                                                     'geowrangler/distance_zonal_stats.py')},
+            'geowrangler.gridding_utils.polygon_fill': { 'geowrangler.gridding_utils.polygon_fill.interpolate_x': ( 'polygon_fill.html#interpolate_x',
+                                                                                                                    'geowrangler/gridding_utils/polygon_fill.py'),
+                                                         'geowrangler.gridding_utils.polygon_fill.scanline_fill': ( 'polygon_fill.html#scanline_fill',
+                                                                                                                    'geowrangler/gridding_utils/polygon_fill.py'),
+                                                         'geowrangler.gridding_utils.polygon_fill.voxel_traversal_2d': ( 'polygon_fill.html#voxel_traversal_2d',
+                                                                                                                         'geowrangler/gridding_utils/polygon_fill.py'),
+                                                         'geowrangler.gridding_utils.polygon_fill.voxel_traversal_scanline_fill': ( 'polygon_fill.html#voxel_traversal_scanline_fill',
+                                                                                                                                    'geowrangler/gridding_utils/polygon_fill.py')},
             'geowrangler.grids': { 'geowrangler.grids.BingTileGridGenerator': ('grids.html#bingtilegridgenerator', 'geowrangler/grids.py'),
                                    'geowrangler.grids.BingTileGridGenerator.__init__': ( 'grids.html#bingtilegridgenerator.__init__',
                                                                                          'geowrangler/grids.py'),
@@ -122,6 +130,28 @@
                                                                                                       'geowrangler/grids.py'),
                                    'geowrangler.grids.BingTileGridGenerator.tile_to_polygon': ( 'grids.html#bingtilegridgenerator.tile_to_polygon',
                                                                                                 'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator': ( 'grids.html#fastbingtilegridgenerator',
+                                                                                    'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator.__init__': ( 'grids.html#fastbingtilegridgenerator.__init__',
+                                                                                             'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator._lat_to_ytile': ( 'grids.html#fastbingtilegridgenerator._lat_to_ytile',
+                                                                                                  'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator._latlng_to_xy': ( 'grids.html#fastbingtilegridgenerator._latlng_to_xy',
+                                                                                                  'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator._lng_to_xtile': ( 'grids.html#fastbingtilegridgenerator._lng_to_xtile',
+                                                                                                  'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator._polygons_to_vertices': ( 'grids.html#fastbingtilegridgenerator._polygons_to_vertices',
+                                                                                                          'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator._xtile_to_lng': ( 'grids.html#fastbingtilegridgenerator._xtile_to_lng',
+                                                                                                  'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator._xy_to_bbox': ( 'grids.html#fastbingtilegridgenerator._xy_to_bbox',
+                                                                                                'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator._xyz_to_quadkey': ( 'grids.html#fastbingtilegridgenerator._xyz_to_quadkey',
+                                                                                                    'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator._ytile_to_lat': ( 'grids.html#fastbingtilegridgenerator._ytile_to_lat',
+                                                                                                  'geowrangler/grids.py'),
+                                   'geowrangler.grids.FastBingTileGridGenerator.generate_grid': ( 'grids.html#fastbingtilegridgenerator.generate_grid',
+                                                                                                  'geowrangler/grids.py'),
                                    'geowrangler.grids.H3GridGenerator': ('grids.html#h3gridgenerator', 'geowrangler/grids.py'),
                                    'geowrangler.grids.H3GridGenerator.__init__': ( 'grids.html#h3gridgenerator.__init__',
                                                                                    'geowrangler/grids.py'),
@@ -165,7 +195,6 @@
                                                                                                               'geowrangler/raster_zonal_stats.py')},
             'geowrangler.spatialjoin_highest_intersection': { 'geowrangler.spatialjoin_highest_intersection.get_highest_intersection': ( 'spatialjoin_highest_intersection.html#get_highest_intersection',
                                                                                                                                          'geowrangler/spatialjoin_highest_intersection.py')},
-            'geowrangler.test_module': {},
             'geowrangler.tile_clustering': { 'geowrangler.tile_clustering.TileClustering': ( 'tile_clustering.html#tileclustering',
                                                                                              'geowrangler/tile_clustering.py'),
                                              'geowrangler.tile_clustering.TileClustering.__init__': ( 'tile_clustering.html#tileclustering.__init__',

geowrangler/gridding_utils/polygon_fill.py

@@ -0,0 +1,261 @@
+# AUTOGENERATED! DO NOT EDIT! File to edit: ../../notebooks/15_polygon_fill.ipynb.
+
+# %% auto 0
+__all__ = ['voxel_traversal_2d', 'scanline_fill', 'voxel_traversal_scanline_fill']
+
+# %% ../../notebooks/15_polygon_fill.ipynb 5
+from typing import List, Tuple, Set, Optional, Dict, Union
+
+import numpy as np
+import pandas as pd
+import polars as pl
+
+# %% ../../notebooks/15_polygon_fill.ipynb 11
+def voxel_traversal_2d(
+    start_vertex: Tuple[int, int],
+    end_vertex: Tuple[int, int],
+    debug: bool = False,  # if true, prints diagnostic info for the algorithm
+) -> List[Tuple[int, int]]:
+    """Returns all pixels between two points as inspired by Amanatides & Woo's “A Fast Voxel Traversal Algorithm For Ray Tracing”"""
+
+    # epsilon is a constant for correcting near-misses in voxel traversal
+    EPSILON = 1e-14
+
+    # Setup initial conditions
+    x1, y1 = start_vertex
+    x2, y2 = end_vertex
+
+    direction_x = 1 if x2 > x1 else -1
+    direction_y = 1 if y2 > y1 else -1
+
+    # Single point
+    if (x1 == x2) and (y1 == y2):
+        pixels = [(x1, y1)]
+        return pixels
+
+    # Vertical line
+    elif x1 == x2:
+        pixels = [(x1, y) for y in range(y1, y2 + direction_y, direction_y)]
+        return pixels
+
+    # Horizontal line
+    elif y1 == y2:
+        pixels = [(x, y1) for x in range(x1, x2 + direction_x, direction_x)]
+        return pixels
+
+    dy = y2 - y1
+    dx = x2 - x1
+    slope = dy / dx
+    inv_slope = dx / dy
+
+    # reverse order if negative slope to preserve symmetry in floating point calculations
+    if slope < 0:
+        x1, y1 = end_vertex
+        x2, y2 = start_vertex
+
+        direction_x = 1 if x2 > x1 else -1
+        direction_y = 1 if y2 > y1 else -1
+
+    slope_multiplier = np.sqrt(1 + slope**2)
+    inv_slope_multiplier = np.sqrt(1 + inv_slope**2)
+
+    pixel_x, pixel_y = x1, y1
+    ray_x, ray_y = pixel_x, pixel_y
+    pixels = [(pixel_x, pixel_y)]
+
+    is_finished = False
+
+    if debug:
+        print(f"\nTraversing from ({x1},{y1}) to ({x2},{y2})")
+
+    # number of steps should not exceed the perimeter of the rectangle enclosing the line segment
+    max_steps = 2 * (abs(dx) + abs(dy))
+    n_steps = 0
+    while not is_finished:
+        # this prevents infinite loops
+        n_steps += 1
+        if n_steps > max_steps:
+            raise Exception(
+                f"Traversal has exceeded steps limit {max_steps:,}. Please recheck inputs"
+            )
+
+        # get the next x or y integer that the next ray would hit
+        if direction_x == 1:
+            next_ray_x = np.floor(ray_x) + 1
+        elif direction_x == -1:
+            next_ray_x = np.ceil(ray_x) - 1
+
+        if direction_y == 1:
+            next_ray_y = np.floor(ray_y) + 1
+        elif direction_y == -1:
+            next_ray_y = np.ceil(ray_y) - 1
+
+        # get distance between the 2 candidates and check which one is closer
+        # there is an epsilon to account near-misses due to floating point differences
+
+        # y coordinate line formula is next_ray_y = ray_y + slope*(next_ray_x-ray_x)
+        # squred distance is (next_ray_x - ray_x)**2 + (slope*(next_ray_x-ray_x))**2
+        # distance simplifies to abs(next_ray_x - ray_x)* sqrt(1+slope**2)
+
+        ray_candidate_1 = (
+            next_ray_x,
+            ray_y + slope * (next_ray_x - ray_x) + direction_y * EPSILON,
+        )
+        # unsimplified square distance
+        # dist_1 = (ray_candidate_1[0] - ray_x)**2 + (ray_candidate_1[1] - ray_y)**2
+        # simplified distance
+        dist_1 = abs(next_ray_x - ray_x) * slope_multiplier
+
+        # x coordinate line formula is next_ray_x = ray_x + inv_slope*(next_ray_y-y)
+        # squared distance is (inv_slope*(next_ray_y-ray_y))**2 + (next_ray_y-ray_y)**2
+        # distance simplifies to abs(next_ray_y-ray_y)* sqrt(1 + inv_slope**2)
+
+        ray_candidate_2 = (
+            ray_x + inv_slope * (next_ray_y - ray_y) + direction_x * EPSILON,
+            next_ray_y,
+        )
+        # unsimplified square distance
+        # dist_2 = (ray_candidate_2[0] - ray_x)**2 + (ray_candidate_2[1] - ray_y)**2
+        # simplified distance
+        dist_2 = abs(next_ray_y - ray_y) * inv_slope_multiplier
+
+        # candidate 1 is closer
+        if dist_1 < dist_2:
+            pixel_x += direction_x
+            ray_x, ray_y = ray_candidate_1
+
+        # candidate 2 is closer
+        elif dist_1 > dist_2:
+            pixel_y += direction_y
+            ray_x, ray_y = ray_candidate_2
+
+        # line passes exactly on the corner
+        elif dist_1 == dist_2:
+            pixel_x += direction_x
+            pixel_y += direction_y
+            ray_x, ray_y = pixel_x, pixel_y
+        else:
+            raise ValueError(f"Erroneous distances {dist_1}, {dist_2}")
+
+        if debug:
+            print(
+                f"Next ray coords are ({ray_x}, {ray_y}) and tile coords are ({pixel_x}, {pixel_y})"
+            )
+
+        pixels.append((pixel_x, pixel_y))
+
+        # checks to see if the loop is finished
+        if direction_x == 1:
+            is_x_finished = pixel_x >= x2
+        elif direction_x == -1:
+            is_x_finished = pixel_x <= x2
+
+        if direction_y == 1:
+            is_y_finished = pixel_y >= y2
+        elif direction_y == -1:
+            is_y_finished = pixel_y <= y2
+
+        if is_x_finished and is_y_finished:
+            break
+
+    return pixels
+
+# %% ../../notebooks/15_polygon_fill.ipynb 15
+def interpolate_x(
+    start_vertex: Tuple[int, int],
+    end_vertex: Tuple[int, int],
+    y: int,
+) -> float:
+    """Interpolate x value for a given y along the line segment defined by start_vertex and end_vertex."""
+    x1, y1 = start_vertex
+    x2, y2 = end_vertex
+    if y1 == y2:
+        # case when there is a horizontal line segment
+        raise ValueError(f"The y value of the 2 vertices should not be the same")
+
+    inverse_slope = (x2 - x1) / (y2 - y1)
+    interpolated_x = x1 + (y - y1) * inverse_slope
+    return interpolated_x
+
+# %% ../../notebooks/15_polygon_fill.ipynb 16
+def scanline_fill(
+    vertices: List[
+        Tuple[int, int]
+    ],  # list of polygon vertices in order (either clockwise or counterclockwise)
+    debug: bool = False,  # if true, prints diagnostic info for the algorithm
+) -> Set[Tuple[int, int]]:
+    """Returns all pixels within the interior of a polygon defined by vertices"""
+
+    offset_vertices = vertices[1:] + vertices[:1]
+
+    if not vertices:
+        return set()
+
+    if len(vertices) == 1:
+        return set(vertices)
+
+    # Calculate the bounding box for the polygon
+    min_y, max_y = min(y for x, y in vertices), max(y for x, y in vertices)
+
+    filled_pixels = set()
+    # Process each horizontal scanline within the bounding box
+    for scanline_y in range(min_y, max_y + 1):
+        intersection_points = []
+
+        # Find intersections of the polygon with the current scanline
+        for start_vertex, end_vertex in zip(vertices, offset_vertices):
+            start_x, start_y = start_vertex
+            end_x, end_y = end_vertex
+
+            if (end_y < scanline_y <= start_y) or (start_y < scanline_y <= end_y):
+                # Calculate x-coordinate of intersection
+                intersection_x = interpolate_x(start_vertex, end_vertex, scanline_y)
+                intersection_points.append(intersection_x)
+
+        # Fill pixels between pairs of intersections
+        if intersection_points:
+            intersection_points.sort()
+
+            filled_pixels_in_row = set()
+            for start_x, end_x in zip(
+                intersection_points[::2], intersection_points[1::2]
+            ):
+                start_x, end_x = int(round(start_x)), int(round(end_x))
+
+                _filled_pixels_in_row = [
+                    (x, scanline_y) for x in range(start_x, end_x + 1)
+                ]
+                filled_pixels_in_row.update(_filled_pixels_in_row)
+
+            filled_pixels.update(filled_pixels_in_row)
+
+        if debug:
+            print(f"Scanline y = {scanline_y}, Intersections: {intersection_points}")
+
+    return filled_pixels
+
+# %% ../../notebooks/15_polygon_fill.ipynb 20
+def voxel_traversal_scanline_fill(
+    vertices_df: Union[
+        pd.DataFrame, pl.DataFrame
+    ],  # dataframe with x_col and y_col for the polygon vertices
+    x_col: str = "x",
+    y_col: str = "y",
+    debug: bool = False,  # if true, prints diagnostic info for both voxel traversal and scanline fill algorithms
+) -> Set[Tuple[int, int]]:
+    """
+    Returns pixels that intersect a polygon
+    This uses voxel traversal to fill the boundary, and scanline fill for the interior. All coordinates are assumed to be nonnegative integers
+    """
+
+    vertices = list(zip(vertices_df[x_col].to_list(), vertices_df[y_col].to_list()))
+    offset_vertices = vertices[1:] + vertices[:1]
+
+    polygon_pixels = set()
+
+    for start_vertex, end_vertex in zip(vertices, offset_vertices):
+        polygon_pixels.update(voxel_traversal_2d(start_vertex, end_vertex, debug))
+
+    polygon_pixels.update(scanline_fill(vertices, debug))
+
+    return polygon_pixels