earthdata-varinfo

A Python package developed as part of the NASA Earth Observing System Data and Information System (EOSDIS) for parsing Earth Observation science granule structure and extracting relations between science variables and their associated metadata, such as coordinates. This package also includes the capability to generate variable (UMM-Var) metadata records that are compatible with the NASA EOSDIS Common Metadata Repository (CMR).

Features:

CFConfig

A class that takes a JSON file and retrieves all related configuration based on the supplied mission name and collection shortname. The JSON file is optional, and if not supplied, a CFConfig class will be constructed with largely empty attributes.

from varinfo import CFConfig

cf_config = CFConfig('ICESat2', 'ATL03', config_file='config/0.0.1/sample_config_0.0.1.json')
cf_attributes = cf_config.get_cf_attributes('/full/variable/path')

VarInfo

A group of classes that contain the relations between all variables within a single granule. Current classes include:

• VarInfoBase: An abstract base class that contains core logic and methods used by the child classes that parse different sources of granule information.
• VarInfoFromDmr: Child class that maps input from a .dmr file downloaded from Hyrax in the cloud. This inherits all the methods and logic of VarInfoBase.
• VarInfoFromNetCDF4: Child class that maps input directly from a NetCDF-4 file. Thus inherits all the methods and logic of VarInfoBase.

from varinfo import VarInfoFromDmr

var_info = VarInfoFromDmr('/path/to/local/file.dmr',
                          config_file='config/0.0.1/sample_config_0.0.1.json')

# Retrieve a set of variables with coordinate metadata:
var_info.get_science_variables()

# Retrieve a set of variables without coordinate metadata:
var_info.get_metadata_variables()

# Augment a set of desired variables with all variables required to support
# the requested set. For example coordinate variables.
var_info.get_required_variables({'/path/to/science/variable'})

# Retrieve an ordered list of dimensions associated with all specified variables.
var_info.get_required_dimensions({'/path/to/science/variable'})

# Retrieve all spatial dimensions associated with the specified set of science
# variables.
var_info.get_spatial_dimensions({'/path/to/science/variable'})

The VarInfoFromDmr and VarInfoFromNetCDF4 classes also have an optional argument short_name, which can be used upon instantiation to specify the short name of the collection to which the granule belongs. This option is to be used when a granule does not contain the collection short name within its metadata global attributes (e.g., ABoVE collections from ORNL).

var_info = VarInfoFromDmr('/path/to/local/file.dmr', short_name='ATL03')

Note: as there are now two optional parameters, short_name and config_file, it is best to ensure that both are specified as named arguments upon instantiation.

UMM-Var generation

earthdata-varinfo can generate variable metadata records compatible with the CMR UMM-Var schema:

from varinfo import VarInfoFromNetCDF4
from varinfo.umm_var import export_all_umm_var_to_json, get_all_umm_var

var_info = VarInfoFromNetCDF4('/path/to/local/file.nc4', short_name='ATL03')
umm_var = get_all_umm_var(var_info)
export_all_umm_var_to_json(list(umm_var.values()), output_dir='local_dir')

Configuration file schema:

The configuration file schema is defined as a JSON schema file in the config directory. Each new iteration to the schema should be placed in its own semantically versioned subdirectory, and a sample configuration file should be provided. Additionally, notes on the schema changes should be provided in config/CHANGELOG.md.

Installing

Using pip

Install the latest version of the package from PyPI using pip:

$ pip install earthdata-varinfo

Other methods:

For local development, it is possible to clone the repository and then install the version being developed in editable mode:

$ git clone https://github.com/nasa/earthdata-varinfo
$ cd earthdata-varinfo
$ pip install -e .

Contributing

Contributions are welcome! For more information see CONTRIBUTING.md.

Developing

Development within this repository should occur on a feature branch. Pull Requests (PRs) are created with a target of the main branch before being reviewed and merged.

Releases are created when a feature branch is merged to main and that branch also contains an update to the VERSION file.

Development Setup:

Prerequisites:

• Python 3.7+, ideally installed in a virtual environment, such as pyenv or conda.
• A local copy of this repository.

Install dependencies:

$ make develop

Run a linter against package code (preferably do this prior to submitting code for a PR review):

$ make lint

Run unittest suite:

$ make test

Releasing:

All CI/CD for this repository is defined in the .github/workflows directory:

• run_tests.yml - A reusable workflow that runs the unit test suite under a matrix of Python versions.
• run_tests_on_pull_requests.yml - Triggered for all PRs against main. It runs the workflow in run_test.yml to ensure all tests pass on the new code.
• publish_to_pypi.yml - Triggered either manually or for commits to the main branch that contain changes to the VERSION file.

The publish_to_pypi.yml workflow will:

• Run the full unit test suite, to prevent publication of broken code.
• Extract the semantic version number from VERSION.
• Extract the release notes for the most recent version from CHANGELOG.md.
• Build the package to be published to PyPI.
• Publish the package to PyPI.
• Publish a GitHub release under the semantic version number, with associated git tag.

Before triggering a release, ensure the VERSION and CHANGELOG.md files are updated accordingly.

Get in touch:

You can reach out to the maintainers of this repository via email:

• david.p.auty@nasa.gov
• owen.m.littlejohns@nasa.gov