Troubleshooting

cfchecker is not installed

Install optional CF extras:

uv sync --extra cf
# or
pip install "nc-check[cf]"

If you do not need external CF checker behavior, you can run heuristic mode:

ds.check.compliance(engine="heuristic", report_format="python")

report_html_file errors

report_html_file is only valid when report_format="html".

Example:

ds.check.compliance(report_format="html", report_html_file="report.html")

Coordinate inference fails for ocean checks

If lon/lat cannot be inferred, pass explicit names:

ds.check.ocean_cover(lon_name="x", lat_name="y", time_name="t")

CLI equivalent:

nc-check ocean-cover input.nc --lon-name x --lat-name y --time-name t

Unexpected time check skips

time_cover can skip a variable if no matching time dimension is found.

Set the preferred time name explicitly:

ds.check.time_cover(time_name="t")

Large datasets

Use lazy opening for low-memory checks:

import xarray as xr
ds = xr.open_dataset("input.nc", chunks={})