I've become interested in what I call representations for my application.  I 
have most of a spec in my company already, I'm wondering if the broader 
community of open source desktops is interested.  If there is already a spec 
that works I cannot find it, but I'll be happy if someone points it to me.

This is about what users see on the user interface.  I believe all "business 
logic" code should strictly work in metric units,  "the system" should have a 
layer (or possibly in the widget toolkit), to do this translation for the user. 
 Of course even when working in metric sometimes the correct unit to work with 
changes - if you are working with something very large or very small then using 
a meter will result in unacceptable floating point loss of precision, but this 
is still less dimensions to keep track of. (and hopefully avoid anything like a 
spaceship crashing because someone assumed the wrong units) 

The US of course hard our weird system. Astronomers typically use light year 
not the metric petametre. In every country historians will have do deal with 
whatever was used before the country adopted metric. There are also regions 
that have not really fully switched to metric resulting in measures like 
kg/acre being in use.

There are a lot of other complex factors that go into what to show.  Often it 
is easy/cheap to measure weight, but if the user wants to see volume the 
conversion gets complex - gravity isn't a constant, your material might not be 
pure, temperature, and pressure are sometimes vary enough to matter, some of 
those variables are easy to measure as well, but others require a lab.  

Even when the measure you want to show is simple, the exact unit can differ for 
different things - airplanes are measured in mm, while most other things that 
large are meters.  Or you might want to see 5meters, 3cm instead of 5.03m.

I am working on an idea that I think captures all the complexity of what 
measures really do in the real world.  Would the freedesk.org community be 
interested in making it into a standard. 

-- 
  Henry Miller
  h...@millerfarm.com

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