cams_api {camsRad}

API client for CAMS radiation service

Description

API client for CAMS radiation service

Usage

cams_api(lat, lng, date_begin, date_end, alt = -999, time_step = "PT01H",
  time_ref = "UT", verbose = FALSE, service = "get_cams_radiation",
  format = "application/csv", filename = "")

Arguments

lat

Latitude, in decimal degrees. Required

lng

Longitude, in decimal degrees. Required

date_begin

Start date as 'yyyy-mm-dd' string. Required

date_end

End date as 'yyyy-mm-dd' string. Required

alt

Altitude in meters, use -999 to let CAMS decide. Default -99

time_step

Aggregation: 'PT01M' for minutes, 'PT15M' for 15 minutes, 'PT01H' for hourly, 'P01D' for daily, 'P01M' for monthly. Deafult 'PT01H'

time_ref

Time reference:'UT' for universal time, 'TST' for true solar time. Default 'UT'

verbose

TRUE for verbose output. Default "FALSE"

service

'get_mcclear' for CAMS McClear data, 'get_cams_radiation' for CAMS radiation data. Default 'get_cams_radiation'

format

'application/csv', 'application/json', 'application/x-netcdf' or 'text/csv'. Default 'application/csv'

filename

path to file on disk to write to. If empty, data is kept in memory. Default empty

Value

list(ok=TRUE/FALSE, response=response). If ok=TRUE, response is the response from httr::GET. If ok=FALSE, response holds exception text

Examples

## Not run: 
library(ncdf4)

filename <- paste0(tempfile(), ".nc")

# API call to CAMS
r <- cams_api(
  60, 15,                       # latitude=60, longitude=15
  "2016-06-01", "2016-06-10",   # for 2016-06-01 to 2016-06-10
  time_step="PT01H",            # hourly data
  service="get_cams_radiation", # CAMS radiation
  format="application/x-netcdf",# netCDF format
  filename=filename)            # file to save to

# Access the on disk stored ncdf4 file
nc <- nc_open(r$response$content)
# list names of available variables
names(nc$var)

# create data.frame with timestamp and global horizontal irradiation
df <- data.frame(datetime=as.POSIXct(nc$dim$time$vals, "UTC",
                                     origin="1970-01-01"),
                 GHI = ncvar_get(nc, "GHI"))

plot(df, type="l")

nc_close(nc)

## End(Not run)