Exercise 7 - Environmental data via OGC API - Environmental Data Retrieval
OGC API - Environmental Data Retrieval provides a Web API to access environmental data using well defined query patterns:
OGC API - Environmental Data Retrieval uses OGC API - Features as a building block, thus enabling streamlined integration for clients and users. EDR can be considered a convenience API which does not require in depth knowledge about the underlying data store/model.
pygeoapi support
pygeoapi supports the OGC API - Environmental Data Retrieval specification by leveraging both feature and coverage provider plugins.
Note
See the official documentation for more information on supported EDR backends
Publish environmental data in pygeoapi
Let's try publishing some ICOADS data via the EDR xarray plugin. The sample ICOADS data can be found in workshop/exercises/data/coads_sst.nc
:
Update the pygeoapi configuration
Open the pygeoapi configuration file in a text editor. Add a new dataset section as follows:
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Save the configuration and restart Docker Compose. Navigate to http://localhost:5000/collections to evaluate whether the new dataset has been published.
At first glance, the icoads-sst
collection appears as a normal OGC API - Coverages collection. Look a bit closer at the collection description, and notice
that there is a `parameter_names' key that describes EDR parameter names for the collection queries.
OWSLib - Advanced
OWSLib is a Python library to interact with OGC Web Services and supports a number of OGC APIs including OGC API - Environmental Data Retrieval.
Interact with OGC API - Environmental Data Retrieval via OWSLib
If you do not have Python installed, consider running this exercise in a Docker container. See the Setup Chapter.
pip3 install owslib
Then start a Python console session with: python3
(stop the session by typing exit()
).
>>> from owslib.ogcapi.edr import EnvironmentalDataRetrieval
>>> w = EnvironmentalDataRetrieval('https://demo.pygeoapi.io/master')
>>> w.url
'https://demo.pygeoapi.io/master'
>>> api = w.api() # OpenAPI document
>>> collections = w.collections()
>>> len(collections['collections'])
13
>>> icoads_sst = w.collection('icoads-sst')
>>> icoads_sst['parameter-names'].keys()
dict_keys(['SST', 'AIRT', 'UWND', 'VWND'])
>>> data = w.query_data('icoads_sst', 'position', coords='POINT(-75 45)', parameter_names=['SST', 'AIRT'])
>>> data # CoverageJSON data
Note
See the official OWSLib documentation for more examples.
Summary
Congratulations! You are now able to publish environmental data to pygeoapi.