satpy.utils module

Module defining various utilities.

satpy.utils.angle2xyz(azi, zen)

Convert azimuth and zenith to cartesian.

satpy.utils.atmospheric_path_length_correction(data, cos_zen, limit=88.0, max_sza=95.0)

Perform Sun zenith angle correction.

This function uses the correction method proposed by Li and Shibata (2006): https://doi.org/10.1175/JAS3682.1

The correction is limited to limit degrees (default: 88.0 degrees). For larger zenith angles, the correction is the same as at the limit if max_sza is None. The default behavior is to gradually reduce the correction past limit degrees up to max_sza where the correction becomes 0. Both data and cos_zen should be 2D arrays of the same shape.

satpy.utils.check_satpy(readers=None, writers=None, extras=None)

Check the satpy readers and writers for correct installation.

Parameters

• readers (list or None) – Limit readers checked to those specified

• writers (list or None) – Limit writers checked to those specified

• extras (list or None) – Limit extras checked to those specified

Returns: bool

True if all specified features were successfully loaded.

satpy.utils.debug(deprecation_warnings=True)

Context manager to temporarily set debugging on.

Example:

>>> with satpy.utils.debug():
...     code_here()

Parameters

deprecation_warnings (Optional[bool]) – Switch on deprecation warnings. Defaults to True.

satpy.utils.debug_off()

Turn debugging logging off.

This disables both debugging logging and the global visibility of deprecation warnings.

satpy.utils.debug_on(deprecation_warnings=True)

Turn debugging logging on.

Sets up a StreamHandler to to sys.stderr at debug level for all loggers, such that all debug messages (and log messages with higher severity) are logged to the standard error stream.

By default, since Satpy 0.26, this also enables the global visibility of deprecation warnings. This can be suppressed by passing a false value.

Parameters

deprecation_warnings (Optional[bool]) – Switch on deprecation warnings. Defaults to True.

Returns

None

satpy.utils.deprecation_warnings_off()

Switch off deprecation warnings.

satpy.utils.deprecation_warnings_on()

Switch on deprecation warnings.

satpy.utils.ensure_dir(filename)

Check if the dir of f exists, otherwise create it.

satpy.utils.get_logger(name)

Return logger with null handler added if needed.

satpy.utils.get_satpos(dataset)

Get satellite position from dataset attributes.

Preferences are:

• Longitude & Latitude: Nadir, actual, nominal, projection

• Altitude: Actual, nominal, projection

A warning is issued when projection values have to be used because nothing else is available.

Returns

Geodetic longitude, latitude, altitude

satpy.utils.in_ipynb()

Check if we are in a jupyter notebook.

satpy.utils.logging_off()

Turn logging off.

satpy.utils.logging_on(level=30)

Turn logging on.

satpy.utils.lonlat2xyz(lon, lat)

Convert lon lat to cartesian.

satpy.utils.proj_units_to_meters(proj_str)

Convert projection units from kilometers to meters.

satpy.utils.recursive_dict_update(d, u)

Recursive dictionary update.

Copied from:

http://stackoverflow.com/questions/3232943/update-value-of-a-nested-dictionary-of-varying-depth

satpy.utils.sunzen_corr_cos(data, cos_zen, limit=88.0, max_sza=95.0)

Perform Sun zenith angle correction.

The correction is based on the provided cosine of the zenith angle (cos_zen). The correction is limited to limit degrees (default: 88.0 degrees). For larger zenith angles, the correction is the same as at the limit if max_sza is None. The default behavior is to gradually reduce the correction past limit degrees up to max_sza where the correction becomes 0. Both data and cos_zen should be 2D arrays of the same shape.

satpy.utils.trace_on()

Turn trace logging on.

satpy.utils.unify_chunks(*data_arrays: xarray.core.dataarray.DataArray) → list[xarray.core.dataarray.DataArray]

Run xarray.unify_chunks() if input dimensions are all the same size.

This is mostly used in satpy.composites.CompositeBase to safe guard against running dask.array.core.map_blocks() with arrays of different chunk sizes. Doing so can cause unexpected results or errors. However, xarray’s unify_chunks will raise an exception if dimensions of the provided DataArrays are different sizes. This is a common case for Satpy. For example, the “bands” dimension may be 1 (L), 2 (LA), 3 (RGB), or 4 (RGBA) for most compositor operations that combine other composites together.

satpy.utils.xyz2angle(x, y, z, acos=False)

Convert cartesian to azimuth and zenith.

satpy.utils.xyz2lonlat(x, y, z, asin=False)

Convert cartesian to lon lat.