Where an Earthdata Login credential is found

Where an Earthdata Login credential is found

Usage

obdaac_credentials()

Value

a list with kind and, for an appkey, key

Why this package cannot avoid it

OB.DAAC requires an Earthdata Login on every data access point. There is no anonymous route, and the failure when you have not got one is unhelpful in a particular way: the server answers HTTP 200 with the login page, so a naive download writes nine kilobytes of HTML into a file called .nc and the error surfaces later as a corrupt netCDF. obdaac_download() checks the bytes for this and says what actually happened.

Setting one up

Register once at https://urs.earthdata.nasa.gov/users/new, then either:

• An appkey, which is the simpler of the two. Generate one at https://oceandata.sci.gsfc.nasa.gov/appkey/ and put it in options(datamatch.earthdata_appkey = "..."), or in the EARTHDATA_APPKEY environment variable. It is a bearer token, so keep it out of scripts you share — .Renviron is the usual home.

• A ~/.netrc, which is what NASA's own examples use and what other tools on your machine may already read: machine urs.earthdata.nasa.gov login USERNAME password PASSWORD. Set it to mode 600. This needs curl on the PATH.

The appkey is preferred where both are present, because it needs no cookie jar and no external program.