generate_grid.py

import shapely.wkt
from shapely.geometry import box

def generate_tiles():

  # width and height of the tiles to generate
  WIDTH, HEIGHT = 1000, 1000

  # from user arbitrary polygon, could be buffered
  all_bbox = shapely.wkt.loads('POLYGON ((531371.13571106398012489 5658034.45453725103288889, 544256.06067719822749496 5658034.45453725103288889, 544256.06067719822749496 5670266.97823927644640207, 531371.13571106398012489 5670266.97823927644640207, 531371.13571106398012489 5658034.45453725103288889))')
  all_area = all_bbox.area

  coords = all_bbox.exterior.coords

  # reset x
  reset_lon = coords[0][0]
  # x
  lon = coords[0][0]
  # y
  lat = coords[0][1]

  covered = 0
  bboxes = []

  col_idx = 0
  row_idx = 0


  while covered < all_area:
     
      bbox = box(lon, lat, lon + WIDTH, lat + HEIGHT)

      intersection = all_bbox.intersection(bbox)
      
      covered += intersection.area
      bboxes.append(bbox)
            
      # catch the very last top row, the first column may already intersect
      if col_idx == 0 and intersection.area < bbox.area:
        pass
      
      # increase Y and reset X 
      elif col_idx > 0 and intersection.area < bbox.area:
        
        # increase row
        lat += HEIGHT
        lon = reset_lon
        
        col_idx = 0
        row_idx += 1
        
        continue

      # just increment column index
      else: 
        col_idx += 1

      lon += WIDTH

  return bboxes