Adding the feature of ERA5 download function using the CDS API #3447
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…t folder that does the download.
| #' | ||
| #' @examples | ||
| #' @author Dongchen Zhang | ||
| ERA5_cds_annual_download <- function(years, months, days, times, area, variables, outdir, auto.create.key = T) { |
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recommend adjusting the function arguments to conform to existing patterns for met download functions. This would mean changing the name to download.ERA5_cds_annual and changing the order of the arguments to start with outfolder, start_date, end_date, then the spatial information, then any function-specific arguments, with required arguments coming before optional ones that have defaults.
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Similar to my comment on the bounding box, I'd recommend that you internally construct the API's odd format for months, days, time, etc from the start and end times
| #' @param months List: a list contains months to be downloaded (e.g., list("01", "02") to download files in Jan and Feb). | ||
| #' @param days List: a list contains days to be downloaded (e.g., list("01", "02") to download files in the first and second days). | ||
| #' @param times List: a list contains times to be downloaded (e.g., list('00:00','03:00') to download files for the times 12:00 and 3:00 am UTC). | ||
| #' @param area Character: a string contains the bounding box (formatted as "North/West/South/East") to be downloaded (e.g., "85/-179/7/-20"). |
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This is a really odd format. Even if this is what the internal API expects, I think it would be a better design to take the bounding box as a vector of numbers and then format this string inside your function.
| #' @examples | ||
| #' @author Dongchen Zhang | ||
| ERA5_cds_annual_download <- function(years, months, days, times, area, variables, outdir, auto.create.key = T) { | ||
| options(timeout=360000) |
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I'd make this an optional argument to the function with a default, rather than hard coding.
| writeLines(c( | ||
| sprintf( | ||
| "url: %s", | ||
| getPass::getPass(msg = "Enter URL from the following link \n (https://cds.climate.copernicus.eu/api-how-to#install-the-cds-api-key):") |
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since getPass is in the suggests, you might add a step in the function that returns an informative error message if it isn't installed
| ) | ||
| # convert grib to nc file. | ||
| nc.path <- gsub(".grib", ".nc", fname, fixed = T) | ||
| cmd <- paste("grib_to_netcdf", fname, "-o", nc.path) |
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what ensures that this command line utility exists in the user's system? it's not in the DESCRIPTION file, nor do you seem to provide any check that the command exists or instructions on how to install it. If you add a check, I'd do it early in the function -- would be a pain to have this function fail AFTER you've done the file download.
| # remove previous grib file. | ||
| unlink(fname) | ||
| } | ||
| return(nc.paths) |
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In keeping with PEcAn met patterns, I recommend returning a more complete results object. Look at other met download functions to see how these are structured. You may be using this function outside of the PEcAn met workflow, but that doesn't me we want to write it so that it can't be used within the PEcAn met workflow.
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