GRIB: missing values

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

[1]:

import numpy as np
import earthkit.data as ekd
ekd.download_example_file("missing.grib")

[2]:

fs = ekd.from_source("file", "missing.grib")

[3]:

fs.ls()

[3]:

	centre	shortName	typeOfLevel	level	dataDate	dataTime	stepRange	dataType	number	gridType
0	ecmf	2t	surface	0	20200513	1200	0	an	0	regular_ll
1	ecmf	msl	surface	0	20200513	1200	0	an	0	regular_ll

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

[4]:

fs.metadata("bitmapPresent")

[4]:

[1, 1]

[5]:

fs.metadata("numberOfMissingValues")

[5]:

[142, 13]

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

[6]:

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

Number of nans=142
Number of nans=13