Harvey,
> Subject: Suggested new units for udunits.dat
> To: netcdfgroup@xxxxxxxxxxxxxxxx
> From: Harvey DAVIES <hld@xxxxxxxxxxxx>
> Keywords: 199507280706.AA11878
In the above message you wrote:
> Here are some suggested new units for the units database file 'udunits.dat'.
>
> CONSTANTS section currently defines 'percent' and '%'. I suggest also
> ppt S 1.0e-3 # parts per thousand
> ppm S 1.0e-6 # parts per million
> ppb S 1.0e-9 # parts per billion
> ppt S 1.0e-12 # parts per trillion
`ppt' in the above is ambiguous. But I can add `ppm' and `ppb'.
> This section also currently defines 'bakersdozen' as 13, which I assume is
> included just for fun.
I forget why `bakersdozen' is in there. The fact that `dozen' wasn't,
however, leads me to suspect that I actually found it in a reference.
> However it may be worthwhile including some other
> common words for numbers such as:
> pair P 2
> ten P 10
> dozen S 12
> score S 20
> hundred P 100
> thousand P 1.0e3
> million P 1.0e6
I don't see a problem adding these.
> billion P 1.0e9
> trillion P 1.0e12
Don't the British use `billion' to mean 1.0e12 (i.e. isn't the British
`billion' the USA's `trillion')?
> UNITS OF LENGTH section currently defines 'printers_point' & 'printers_pica'.
> I suggest changing definition of latter from
> printers_pica P 4.217518e-3 meter
> to
> printers_pica P 12 printers_point # exact
Ok.
> I suggest allowing following aliases
> point P printers_point
> pica P printers_pica
> pc P printers_pica
> The abbreviation 'pt' is often used for printers_point, but this is already
> defined as pint!
Yes, one has to be carefull with abreviations. `pt' is commonly used for
pint. I won't add `pc' because it can be confused with `pico c' (i.e.
0.0002997925 meter second-1).
> Another important printing unit of length is the 'big point', as used in
> PostScript. This has the abbreviation 'bp'. So I suggest:
> big_point P inch/72 # exact
Ok.
> bp S big_point
I'm wary of adding too many 2-character abbreviations but will if
pressed. What do you think?
> UNITS OF TIME section currently defines 'fortnight', but not 'week' or
> 'month'!
> I suggest following:
> week P 7 day
> lunar_month P 29.530859 day
Ok.
> month P year/12 # mean calendar month
I'll add this -- even though a month isn't a twelfth of a year. I
suppose it might be convenient.
> sidereal_month P 27.321661 day
> tropical_month P 27.321582 day
I don't have a reference handy and the above aren't 1/12 of the
corresponding years. Are you certain about the coefficients?
--------
Steve Emmerson <steve@xxxxxxxxxxxxxxxx>
