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Unidata / UDUNITS-2

API and utility for arithmetic manipulation of units of physical quantities
http://www.unidata.ucar.edu/software/udunits
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no_unit #26

Closed marqh closed 9 years ago

marqh commented 9 years ago

Hello

The CF community would like to explore the additon of a new 'unit' to udunits, that of 'no_unit'

We would like this to be an accepted string for a unit according to udunits, with the same behaviour as a unit of '' That is, that it will not operate or compare with any other unit, it is not a unit. This is important for capturing categorical entities, where no unit of measure is to be used. The syntax of unit = '' is deemed unclear by the community, who would prefer an explicit and human readable version unit = 'no_unit'

For a long time in CF a lack of a units string has been equivalent to a unit of '1' which has markedly different behaviour, so we cannot just omit the unit in these cases.

As CF defers to udunits for 'what is a valid unit' it would be very helpful if this could be included.

I have looked into the xml files to see if I could add this, but I cannot see how to define the null behaviour we get if we have a unit of ''

thank you mark

marqh commented 9 years ago

There has been extensive discussion within CF about this topic, which makes me concerned that this is not a helpful approach

On that basis I'd like to close this ticket