Control `timeVariation()` lower panels

[jack-davison]

This PR adds the panels argument to timeVariation().

It allows users to control the order and presence of the lower three panels of the timeVariation() plot.

Notes:

• This supersedes month.last, which now doesn't do anything. It's still listed as an argument, but users just get a warning to use panels instead.

• You can't provide nothing to panels (i.e., you can't just get the day.hour panel on it's own). The best way to isolate a panel is to just run timeVariation() and pull it from the openair object.

• I can think of two key benefits to dropping panels:

  • If only one month of data has been used, the month panel often looks rubbish so could just be dropped.
  • If the hour panel doesn't provide greater insight compared to to the hour.day panel, it too could be dropped.

• This adds space for more panels, if there was future interest. For example, a daylight panel, or season panel.

devtools::load_all()
#> ℹ Loading openair

# default
timeVariation(mydata, "pm10")

# rejig the bottom panel
timeVariation(mydata, "pm10", panels = c("month", "day", "hour"))

# what if only one month of data is being used? looks crap
timeVariation(selectByDate(mydata, month = 1, year = 2000),
              "pm10",
              panels = c("month", "day", "hour"))

# get rid of the month panel
timeVariation(selectByDate(mydata, month = 1, year = 2000),
              "pm10",
              panels = c("day", "hour"))

^{Created on 2024-04-28 with reprex v2.0.2}

[jack-davison]

Converted this to draft as I need to understand how the xlab argument works and interacts with this!