satpy.dataset.data_dict module

Classes and functions related to a dictionary with DataID keys.

class satpy.dataset.data_dict.DatasetDict

Bases: dict

Special dictionary object that can handle dict operations based on dataset name, wavelength, or DataID.

Note: Internal dictionary keys are DataID objects.

contains(item)

Check contains when we know the exact DataID.

get(key, default=None)

Get value with optional default.

get_key(match_key, num_results=1, best=True, **dfilter)

Get multiple fully-specified keys that match the provided query.

Parameters

• key (DataID) – DataID of query parameters to use for searching. Any parameter that is None is considered a wild card and any match is accepted. Can also be a string representing the dataset name or a number representing the dataset wavelength.

• num_results (int) – Number of results to return. If 0 return all, if 1 return only that element, otherwise return a list of matching keys.

• **dfilter (dict) – See get_key function for more information.

getitem(item)

Get Node when we know the exact DataID.

keys(names=False, wavelengths=False)

Give currently contained keys.

exception satpy.dataset.data_dict.TooManyResults

Bases: KeyError

Special exception when one key maps to multiple items in the container.

satpy.dataset.data_dict.get_best_dataset_key(key, choices)

Choose the “best” DataID from choices based on key.

To see how the keys are sorted, refer to :meth:satpy.datasets.DataQuery.sort_dataids.

This function assumes choices has already been filtered to only include datasets that match the provided key.

Parameters

• key (DataQuery) – Query parameters to sort choices by.

• choices (iterable) – DataID objects to sort through to determine the best dataset.

Returns: List of best DataID`s from `choices. If there is more

than one element this function could not choose between the available datasets.

satpy.dataset.data_dict.get_key(key, key_container, num_results=1, best=True, query=None, **kwargs)

Get the fully-specified key best matching the provided key.

Only the best match is returned if best is True (default). See get_best_dataset_key for more information on how this is determined.

query is provided as a convenience to filter by multiple parameters at once without having to filter by multiple key inputs.

Parameters

• key (DataID) – DataID of query parameters to use for searching. Any parameter that is None is considered a wild card and any match is accepted.

• key_container (dict or set) – Container of DataID objects that uses hashing to quickly access items.

• num_results (int) – Number of results to return. Use 0 for all matching results. If 1 then the single matching key is returned instead of a list of length 1. (default: 1)

• best (bool) – Sort results to get “best” result first (default: True). See get_best_dataset_key for details.

• query (DataQuery) –

  filter for the key which can contain for example:

  resolution (float, int, or list): Resolution of the dataset in

  dataset units (typically meters). This can also be a list of these numbers.

  calibration (str or list): Dataset calibration

  (ex.’reflectance’). This can also be a list of these strings.

  polarization (str or list): Dataset polarization

  (ex.’V’). This can also be a list of these strings.

  level (number or list): Dataset level (ex. 100). This can also be a

  list of these numbers.

  modifiers (list): Modifiers applied to the dataset. Unlike

  resolution and calibration this is the exact desired list of modifiers for one dataset, not a list of possible modifiers.

Returns

Matching key(s)

Return type

list or DataID

Raises: KeyError if no matching results or if more than one result is

found when num_results is 1.