OS Terrain50 to GeoTIFF

osterrain50.py

# https://gis.stackexchange.com/a/462686/2856
# CC-BY-SA 4.0

import os
import zipfile
from osgeo import gdal

gdal.UseExceptions()

input = "/path/to/terr50_gagg_gb.zip"
output = input.replace(".zip", ".tif")

srs = "EPSG:27700"

zips = (z for z in zipfile.ZipFile(input).namelist() if z.endswith(".zip"))
vrts = []

for zip in zips:
    basename = os.path.basename(zip)[0:4].upper()
    asc = "/vsizip/{/vsizip/{%s}/%s}/%s.asc" % (input, zip, basename)
    vrt = f"/vsimem/{basename}.vrt"
    gdal.Translate(vrt, asc, outputType=gdal.GDT_Float32)
    vrts.append(vrt)

vrt = f"/vsimem/terr50_gagg_gb.vrt"
gdal.BuildVRT(f"/vsimem/terr50_gagg_gb.vrt", vrts)
gdal.Translate(output, vrt, outputSRS=srs, creationOptions=["TILED=YES", "COMPRESS=LZW", "PREDICTOR=2"])