--- a/compute-regions.py Tue Sep 25 22:22:10 2018 +0300
+++ b/compute-regions.py Wed Sep 26 13:12:11 2018 +0300
@@ -4,54 +4,93 @@
from geometry import *
from zipfile import ZipFile
from configparser import ConfigParser
-from regions import parse_regions
-
-representatives = {}
-
-regions = parse_regions(sys.argv[2])
-bus_stops = {}
-block_factor = 0.005
class Blockmap:
- ''' Models a map of blocks. Maps each location to a square area. '''
+ '''
+ Models a map of blocks. Maps each location to a square area.
+ '''
+ block_factor = 0.005
def __init__(self, default = None):
from collections import defaultdict
self.blocks = default or defaultdict(set)
def __getitem__(self, blockid):
- ''' Returns a block for block coordinates. The block is a set that can contain anything. '''
+ '''
+ Returns a block for block coordinates. The block is a set that can
+ contain anything.
+ '''
return self.blocks[blockid]
def blockpoint(self, point):
- ''' Returns a block point for a location. The block point is a coordinate in the blockmap. '''
- return int(point.x / block_factor), int(point.y / block_factor)
+ '''
+ Returns a block point for a location. The block point is a
+ coordinate in the blockmap.
+ '''
+ block_coordinate = lambda x: int(x / self.block_factor)
+ return block_coordinate(point.x), block_coordinate(point.y)
+
+def minmax(data):
+ '''
+ Computes the minimum and maximum values in one-pass using only
+ 1.5*len(data) comparisons
+ '''
+ import itertools
+ it = iter(data)
+ try:
+ lo = hi = next(it)
+ except StopIteration:
+ raise ValueError('minmax() arg is an empty sequence')
+ for x, y in itertools.zip_longest(it, it, fillvalue = lo):
+ if x > y:
+ x, y = y, x
+ lo = min(x, lo)
+ hi = max(y, hi)
+ return lo, hi
def blocks_in_shape(blockmap, shape):
- ''' Finds all blocks inside the bounding box of a shape. '''
- min_x = min(point.x for point in shape.points)
- min_y = min(point.y for point in shape.points)
- max_x = max(point.x for point in shape.points)
- max_y = max(point.y for point in shape.points)
+ '''
+ Finds all blocks inside the bounding box of a shape.
+ '''
+ from itertools import product
+ min_x, max_x = minmax(point.x for point in shape.points)
+ min_y, max_y = minmax(point.y for point in shape.points)
min_blockpoint = blockmap.blockpoint(Location(min_x, min_y))
max_blockpoint = blockmap.blockpoint(Location(max_x, max_y))
- for x in range(min_blockpoint[0], max_blockpoint[0] + 1):
- for y in range(min_blockpoint[1], max_blockpoint[1] + 1):
- yield blockmap[x, y]
+ range_x = range(min_blockpoint[0], max_blockpoint[0] + 1)
+ range_y = range(min_blockpoint[1], max_blockpoint[1] + 1)
+ yield from (blockmap[x, y] for x, y in product(range_x, range_y))
-def main():
- with ZipFile(sys.argv[1]) as archive:
+def location_from_row(row):
+ return Location(float(row['stop_lat']), float(row['stop_lon']))
+
+def read_bus_stops(archive_path):
+ bus_stops = dict()
+ with ZipFile(archive_path) as archive:
with archive.open('stops.txt') as file:
- for row in read_csv(map(bytes.decode, file)):
- location = Location(float(row['stop_lat']), float(row['stop_lon']))
- reference = row['stop_id']
- bus_stops[reference] = location
- region_shapes = list()
- districts = dict()
- bus_stop_regions = dict()
+ return {
+ row['stop_id']: location_from_row(row)
+ for row in read_csv(map(bytes.decode, file))
+ }
+
+def create_blockmap(regions):
+ '''
+ Creates a blockmap of regions
+ '''
blockmap = Blockmap()
- # Find all regions for every block.
for region in regions.values():
for block in blocks_in_shape(blockmap, region['shape']):
set.add(block, region['name'])
+ return blockmap
+
+def get_args():
+ from argparse import ArgumentParser
+ parser = ArgumentParser()
+ parser.add_argument('gtfs_zip')
+ parser.add_argument('mapfile')
+ return parser.parse_args()
+
+def compute_bus_stop_regions(regions, bus_stops):
# Find the region every node is in
+ blockmap = create_blockmap(regions)
+ bus_stop_regions = dict()
for stop_id, stop_position in bus_stops.items():
for region_name in blockmap[blockmap.blockpoint(stop_position)]:
region = regions[region_name]
@@ -60,9 +99,21 @@
break
else:
bus_stop_regions[stop_id] = None
+ return bus_stop_regions
+
+def percentage(a):
+ return '%.1f%%' % (a * 100)
+
+def main():
+ from regions import parse_regions
+ args = get_args()
+ regions = parse_regions(args.mapfile)
+ bus_stops = read_bus_stops(args.gtfs_zip)
+ bus_stop_regions = compute_bus_stop_regions(regions, bus_stops)
covered = sum(1 if value else 0 for value in bus_stop_regions.values())
total = len(bus_stops)
- print('%.1f%% bus stops covered.' % (covered * 100 / total), file = sys.stderr)
+ print('%s bus stops covered.' % percentage(covered / total),
+ file = sys.stderr)
json.dump(bus_stop_regions, sys.stdout, indent = 2)
if __name__ == '__main__':