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@celoyd
Last active September 14, 2023 21:38
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Draw an OSM daily aggregate tile traffic log to an image (proof of concept quality)
"""
draw_osm_day.py osm_tile_traffic_file.txt output_image.tiff
Write a float32 TIFF representing tile traffic in the OSM aggregate log.
Charlie Loyd, 2023-09-14. Inspired by https://en.osm.town/@pnorman/111062780453196500.
I recommend downloading the .xz compressed files and using xzcat to feed
them to this script. (Doing xz decompression in-script was slow.) E.g.,
$ xzcat tiles-2022-03-15.txt.xz | python draw_osm_day.py - test.tiff
Alpha quality. Gotchas:
- zoom level is hard-coded
- ignores records below zoom level
- does no weighting or scaling of any kind
- etc.
"""
import numpy as np
from skimage import io
from sys import argv
src = argv[1]
if src == '-':
src = '/dev/stdin'
draw_zl = 10
edge_length = int(2**draw_zl)
dst = np.zeros((edge_length, edge_length), dtype=np.float32)
for line in open(src):
zxy, count = line.split(" ")
z, x, y = [int(el) for el in zxy.split("/")]
# z, x, y are original tile coords. We convert those
# to pixel coords px and py, which are equivalent to
# what the tile at xyz would be covered by at z=zl.
# If input z is below zl (would be multiple pixels),
# we skip it.
zdiff = z - draw_zl
if zdiff < 0:
continue
px, py = [d >> zdiff for d in (x, y)]
dst[py, px] += float(count)
# Here you might run dst through, say, log10.
io.imsave(argv[2], dst)
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