GRIB: missing values

We read a GRIB file containing 2 messages with missing values using from_source(). First we ensure the example file is available.

import numpy as np

import earthkit.data as ekd

ekd.download_example_file("missing.grib")

ds = ekd.from_source("file", "missing.grib").to_fieldlist()

ds.ls()

	parameter.variable	time.valid_datetime	time.base_datetime	time.step	vertical.level	vertical.level_type	ensemble.member	geography.grid_type
0	2t	2020-05-13 12:00:00	2020-05-13 12:00:00	0 days	0	surface	0	regular_ll
1	msl	2020-05-13 12:00:00	2020-05-13 12:00:00	0 days	0	surface	0	regular_ll

When can see how many missing values we have by inspecting the metadata:

ds.metadata("bitmapPresent")

[1, 1]

ds.metadata("numberOfMissingValues")

[142, 13]

When data values are extracted as numpy arrays missing values are automatically replaced by np.nan:

for f in ds:
    v = f.values
    print(f"Number of nans={np.count_nonzero(np.isnan(v))}")

Number of nans=142
Number of nans=13