Becquerels Show as Hertz

[tombishop1]

When attempting to assign the units Bq, they are only recognised as Hz. I'm guessing this is because they share the same def, 1/s, as they are both measurements of frequency, but they do have subtly different definitions.

set_units(1:5, "Bq") Units: [Hz] [1] 1 2 3 4 5

[Enchufa2]

Unfortunately, this is how udunits2 works. E.g., with the thinnest wrapper we have around parsing and formatting,

> units:::R_ut_format(units:::R_ut_parse("Bq"))
[1] "Hz"

And this is because Bq is defined as an alias of 1/s, which is already assigned to Hz. You could bring this issue upstream.

[tombishop1]

Understood, I'll look at the options there. Is there a hack to remove one of entries (e.g. delete Hz) for the duration of a session? I've tried remove_unit(name = "hertz"), but even then set_units(1:5, "Bq") still returns Units: [Hz]. That's odd to me, because set_units(1:5, "Hz") throws an error, as would be expected.

> set_units(1:5, "Hz")
Units: [Hz]
[1] 1 2 3 4 5
> remove_unit(name = "hertz")
> set_units(1:5, "Hz")
Units: [Hz]
[1] 1 2 3 4 5
> set_units(1:5, "Bq")
Units: [Hz]
[1] 1 2 3 4 5

[Enchufa2]

Yeap, that's odd. This worked for me:

> remove_unit(c("Hz", "Bq"))
> install_unit("Bq", "1/s")
> set_units(1:5, "Bq")
Units: [Bq]
[1] 1 2 3 4 5

[tombishop1]

Yes, that works for me too, so I guess we can close this for now, and perhaps I'll open an issue upstream. Inspecting udunits2-derived.xml, there is a special entry for "SI derived units with special names and symbols admitted for reasons of safeguarding human health", containing Bq, Gy and Sv. The entry for Bq contains a comment that it is "an alias because 1/s is already mapped to Hz". I'm guessing udunits2 is converting from the alias without considering the exception for human health.