modis_shapes.py

# UPDATE: Instead of using this script, you should probably
# use http://web.archive.org/web/2021id_/https://modis.ornl.gov/files/modis_sin.kmz

#!/usr/bin/env python3

"""
Draw the shapes of tiles used by Moderate Resolution Imaging
Spectroradiometer (MODIS) satellite products. The output is a TSV file
with the shapes as well-known text (WKT) that can be read into QGIS.
"""

# Adjust these for visibility.
lon_limits = [-175, -40]
lat_limits = [-90, 90]

from pathlib import Path

# From: https://web.archive.org/web/2021id_/https://modis-land.gsfc.nasa.gov/pdf/sn_gring_10deg.txt
# linked from: https://modis-land.gsfc.nasa.gov/MODLAND_grid.html
inp = Path("/tmp/sn_gring_10deg.txt").read_text()

out = []
for line in inp.splitlines():
    if not (line and line.lstrip()[0].isdigit()):
        continue
    v, h, *coords = line.split()
    points = [
        (float(coords[i]), float(coords[i + 1]))
        for i in list(range(0, len(coords), 2)) + [0]]
    if any(lon == -999 or lat == -99 for lon, lat in points):
        continue
    if any(
            not (lon_limits[0] <= lon <= lon_limits[1] and
                lat_limits[0] <= lat <= lat_limits[1])
            for lon, lat in points):
        continue
    out.append(dict(h = h, v = v, geom =
        'LINESTRING ({})'.format(', '.join(
            ' '.join(map(str, p)) for p in points))))

out.sort(key = lambda d: (d['h'], d['v']))
print('\t'.join(out[0].keys()))
for o in out:
    print('\t'.join(o.values()))