Incorrect square foot to acre conversion

[iembry]

Hi, I'm using units version 0.8-0 and I have come across the following incorrect conversion:

ft2 <- set_units(43560, ft ^ 2)

acre <- ft2

units(acre) <- make_units(acre)

0.999996 [acre]

According to the UDUNITS-2 database, an acre is "unit of area in the US Customary System, used in land and sea floor measurement, equal to 43560 square feet".

Please correct the conversion error.

Thank you.

Irucka

[edzer]

> set_units(1, acre) |> set_units(foot^2)
43560.17 [foot^2]

The R units package uses the C udunits library, but doesn't define it. If you believe this is an error, you need to report it upstream.

[edzer]

For instance, the udunits2 command line tool gives

$ udunits2
You have: 1 acre
You want: foot^2
    1 acre = 43560.2 foot^2
    x/foot^2 = 43560.2*(x/acre)

(and seems to round to 6 digits)

[Enchufa2]

@iembry The conversion is fine. You just didn't use the proper foot.

ft2 <- set_units(43560, US_survey_foot ^ 2)
acre <- ft2
units(acre) <- make_units(acre)
acre
#> 1 [acre]

set_units(as_units("US_survey_foot"), foot)
#> 1.000002 [foot]

¯_(ツ)_/¯

[iembry]

@ Enchufa2 Thank you for your suggestion! I'll use the proper foot unit.