COVIDcast Metadata

The COVIDcast metadata endpoint (endpoint covidcast_meta) provides a list of all sources and signals available in the API, along with basic summary statistics such as the dates they are available, their minimum and maximum values, and the geographic levels at which they are reported.

The API

The base URL is: https://api.delphi.cmu.edu/epidata/covidcast_meta/

Parameters

None required.

Response

Field	Description	Type
result	result code: 1 = success, 2 = too many results, -2 = no results	integer
epidata	list of results, one per name/geo_type pair	array of objects
epidata[].data_source	data source	string
epidata[].signal	signal name	string
epidata[].time_type	temporal resolution of the signal (e.g., day, week)	string
epidata[].geo_type	geographic resolution (e.g. county, hrr, msa, dma, state)	string
epidata[].min_time	minimum observation time	integer (YYYYMMDD)
epidata[].max_time	maximum observation time	integer (YYYYMMDD)
epidata[].num_locations	number of distinct geographic locations with data	integer
epidata[].min_value	minimum value	float
epidata[].max_value	maximum value	float
epidata[].mean_value	mean of value	float
epidata[].stdev_value	standard deviation of value	float
epidata[].last_update	most recent date when data was updated	integer (YYYYMMDD)
epidata[].max_issue	most recent date data was issued	integer (YYYYMMDD)
epidata[].min_lag	smallest lag from observation to issue, in time_type units	integer
epidata[].max_lag	largest lag from observation to issue, in time_type units	integer
message	success or error message	string

Example URLs

https://api.delphi.cmu.edu/epidata/covidcast_meta/

{
  "result": 1,
  "epidata": [
  {
      "data_source": "doctor-visits",
      "signal": "smoothed_adj_cli",
      "last_update": 1592707979,
      "stdev_value": 2.6647410028331,
      "num_locations": 2500,
      "time_type": "day",
      "max_value": 87.190476,
      "mean_value": 1.4439366759191,
      "geo_type": "county",
      "min_value": 0,
      "max_time": 20200617,
      "min_time": 20200201
    },
    ...
  ],
  "message": "success"
}

Code Samples

Python and R users are advised to use the dedicated API client, which provides support to return metadata as a data frame. The Python client includes a metadata() method for this purpose, while the R client offers a covidcast_meta() function to achieve the same.

Alternatively, libraries are available for JavaScript, Python, and R. The following samples show how to import the library and fetch Delphi’s COVID-19 Surveillance Streams metadata.

Optionally install the package using pip(env):

pip install delphi-epidata

Otherwise, place delphi_epidata.py from this repo next to your python script.

# Import
from delphi_epidata import Epidata
# Fetch data
res = Epidata.covidcast_meta()
print(res['result'], res['message'], len(res['epidata']))

# Import
source('delphi_epidata.R')
# Fetch data
res <- Epidata$covidcast_meta()
cat(paste(res$result, res$message, length(res$epidata), "\n"))

<!-- Imports -->
<script src="delphi_epidata.js"></script>
<!-- Fetch data -->
<script>
  EpidataAsync.covidcast_meta().then((res) => {
    console.log(res.result, res.message, res.epidata != null ? res.epidata.length : 0);
  });
</script>