`time` argument of `get_pvol` could be more flexible

[bart1]

currently time should be a POSIXct rounded to 5 minutes we might consider also allowing for intervals and multiple timestamps. The individual functions now only download one file at a time and do not parallelize requests.

[peterdesmet]

• For internal functions, I would pass POSIXct in UTC.
• For user facing functions, I would allow POSIXct and ISO strings, which are then converted with lubridate
• Would be good to support intervals, as lubridate or base durations
• There should be a translation from user-provided timestamp/interval, to closest matching precision (e.g. 5 min)
• Parallelisation will be useful/necessary at some point

[bart1]

We tend to refer to the volume radar data in 5 minutes intervals but I think sometimes there is a bit of ambiguity to what time the radar data refers. The time in the data for in cz is for example 4 minutes after the reference time. Although the scans start pretty much directly at the reference time. I would need to look a bit more into this

require(getRad)
#> Loading required package: getRad
pv<-get_pvol("czska",t<- as.POSIXct(Sys.Date())+lubridate::hours(3))
t
#> [1] "2024-10-15 03:00:00 UTC"
pv$datetime
#> [1] "2024-10-15 03:04:12 UTC"
bioRad::attribute_table(pv, select=c("where.elangle","what.endtime","what.starttime"))[,-4] 
#>    what.endtime what.starttime where.elangle
#>          030412         030345           0.1
#> 1        030343         030316           0.5
#> 2        030314         030251           0.9
#> 3        030250         030227           1.3
#> 4        030225         030202           1.7
#> 5        030201         030138           2.2
#> 6        030136         030114           3.2
#> 7        030112         030100           4.5
#> 8        030058         030045           6.3
#> 9        030041         030030           8.7
#> 10       030027         030016          13.7
#> 11       030013         030003          21.6

[bart1]

Now time can be a vector rounded to the nearest 5 minutes and is checked, parallelization / request optimization I will leave for later