mapperly_top.py

from skimage import io
from pathlib import Path
from sys import argv

srtm_dir = Path(argv[1])

width = 3601  # pixel width of one of these srtm tiffs

starting_lon = -2
ending_lon = 143


def format_lon(lon):
    # convert -1 -> "W001", 17 -> "E017", etc.
    ew = "E" if lon >= 0 else "W"
    lon = abs(lon)
    return f"{ew}{lon:03}"


def make_tiff_path(lon):
    lon = format_lon(lon)
    path = Path(srtm_dir / f"N52{lon}.tif")
    return path


def row(lon):
    path = make_tiff_path(lon)
    if path.is_file():
        row = io.imread(path)[0, :]
    else:
        # This will be a list, not a numpy array.
        # We’ll just `for` through it, so it doesn’t matter.
        row = [0] * width
    return row


for lon in range(starting_lon, ending_lon + 1):
    r = row(lon)
    for e in r:
        print(e)