ERDDAP ERDDAPY

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Revision as of 13:41, 19 January 2022 by Jpa029 (talk | contribs)

How to use erddapy

instantiate the ERDDAP server

First of all, we need to instantiate the ERDDAP URL constructor for a server.

server
an ERDDAP server URL or an acronym for one of the builtin servers.


from erddapy import ERDDAP
import pandas as pd
e = ERDDAP(server="https://erddap.bcdc.no/erddap")

Let’s explore the methods and attributes available in the ERDDAP object
Note: All the methods prefixed with get_ will return a valid ERDDAP URL for the requested response and options.

[method for method in dir(e) if not method.startswith("_")]

['auth', 'constraints', 'dataset_id', 'get_categorize_url', 'get_download_url', 'get_info_url', 'get_search_url', 'get_var_by_attr', 'protocol', 'relative_constraints', 'requests_kwargs', 'response', 'server', 'server_functions', 'to_iris', 'to_ncCF', 'to_pandas', 'to_xarray', 'variables']

help(e.get_search_url)
Help on method get_search_url in module erddapy.erddapy:
get_search_url(response: Union[str, NoneType] = None, search_for: Union[str, NoneType] = None, protocol: Union[str, NoneType] = None, items_per_page: int = 1000, page: int = 1, **kwargs) -> str method of erddapy.erddapy.ERDDAP instance
The search URL for the `server` endpoint provided.
Args:
search_for: "Google-like" search of the datasets' metadata.
- Type the words you want to search for, with spaces between the words.
ERDDAP will search for the words separately, not as a phrase.
- To search for a phrase, put double quotes around the phrase (for example, `"wind speed"`).
- To exclude datasets with a specific word, use `-excludedWord`.
- To exclude datasets with a specific phrase, use `-"excluded phrase"`
- Searches are not case-sensitive.
- You can search for any part of a word. For example, searching for `spee` will find datasets with `speed` and datasets with `WindSpeed`
- The last word in a phrase may be a partial word. For example, to find datasets from a specific website (usually the start of the datasetID), include (for example) `"datasetID=erd"` in your search.
response: default is HTML.
items_per_page: how many items per page in the return, default is 1000.
page: which page to display, default is the first page (1).
kwargs: extra search constraints based on metadata and/or coordinates ke/value.
metadata: `cdm_data_type`, `institution`, `ioos_category`, `keywords`, `long_name`, `standard_name`, and `variableName`.
coordinates: `minLon`, `maxLon`, `minLat`, `maxLat`, `minTime`, and `maxTime`.
Returns:
url: the search URL.

access to the list of all datasets available through this ERDDAP server

Here we use the get_search_url method

# show all datasets
url = e.get_search_url()
print(url)

https://erddap.icos-cp.eu/erddap/search/advanced.html?page=1&itemsPerPage=1000&protocol=(ANY)&cdm_data_type=(ANY)&institution=(ANY)&ioos_category=(ANY)&keywords=(ANY)&long_name=(ANY)&standard_name=(ANY)&variableName=(ANY)&minLon=(ANY)&maxLon=(ANY)&minLat=(ANY)&maxLat=(ANY)

we also specify the response attribute in our ERDDAP instance.

response
specifies the type of table data file that you want to download (default **html**)
# show all datasets
e.response='csv'
url = e.get_search_url(search_for="all")
df = pd.read_csv(url)
df[['griddap','tabledap','Dataset ID']].head()
griddap tabledap Dataset ID
0 NaN https://erddap.icos-cp.eu/erddap/tabledap/allD... allDatasets
1 NaN https://erddap.icos-cp.eu/erddap/tabledap/icos... icos26na20170409SocatEnhanced
2 NaN https://erddap.icos-cp.eu/erddap/tabledap/icos... icos26na20170421SocatEnhanced
3 NaN https://erddap.icos-cp.eu/erddap/tabledap/icos... icos26na20170430SocatEnhanced
4 NaN https://erddap.icos-cp.eu/erddap/tabledap/icos... icos26na20170511SocatEnhanced


access to the list of datasets by type (grid, tabular,..)