This is a brief overview of some of the more advanced options in the
A ‘hidden’ feature of the
wf_set_key() function is that it returns the user name upon success. This allows for easier integration in scripts shared with users (which have different credentials)
The conversion from a MARS or python based queries (formed on the ECMWF or Copernicus CDS websites) to the list format used by
ecmwfr can be automated if you use the RStudio based Addin.
By selecting and using Addin -> Mars to list (or ‘Python to list’) you dynamically convert queries copied from either ECMWF or CDS based services.
Addin is the sure way to form a proper
ecmwfr request and avoids typos. As such, we recommend the use of the
Another hidden feature of
ecmwfr is the fact that the request is the first argument in the
wf_request() function. This means that any valid list can be piped into this function (using the %>% or pipe symbol).
Once a valid request has been created it can be made into a dynamic function using
achetypes. Archetype functions are build using a valid
ecmwfr ECMWF or CDS request and the vector naming the field which are to be set as dynamic.
wf_archetype() function creates a new function with as parameters the dynamic fields previously assigned. The below example show how to use the function to generate the custom
dynamic_request() function. We then use this new function to alter the
date fields and pipe (%>%) into the
wf_request() function to retrieve the data.
# this is an example of a request dynamic_request <- wf_archetype(request = list( stream = "oper", levtype = "sfc", param = "167.128", dataset = "interim", step = "0", grid = "0.75/0.75", time = "00", date = "2014-07-01/to/2014-07-02", type = "an", class = "ei", area = "73.5/-27/33/45", format = "netcdf", target = "tmp.nc"), dynamic_fields = c("area","date")) # change only the date to a single day dynamic_request(date = "2014-07-01")