Modeling Volume Per Acre

[jkorba-rantizo]

I would like to create quantities as volume per acre (e.g. gallons per acre, pints per acre, quarts per acre, etc.), and they need to be serializable as part of a REST api via Jackson.

1. What would be the best way to represent these quantities?
2. I have tried just to get acres serializing properly, and the unit isn't being printed correctly. It appears the only library that has acres defined is systems.uom:systems-common:2.1, so I've been using that along with the UnitJacksonModule module from tech.uom.lib:uom-lib-jackson:2.1 for serializing.

Simple test (kotlin):

import javax.measure.Quantity
import javax.measure.quantity.Area
import org.junit.jupiter.api.Test
import systems.uom.common.Imperial
import tech.units.indriya.quantity.Quantities

class UnitsTest {

    @Test
    fun test() {
        val acres : Quantity<Area> = Quantities.getQuantity(5, Imperial.ACRE)
        
        print(objectMapper.writeValueAsString(acres))
    }
    
}

and the output:

{"unit":"((m.3048)/100002).43560","scale":"ABSOLUTE","value":5}

I was expecting the unit to be "ac" or similar. Am I out to lunch?

Any guidance is much appreciated.