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Subject:	Re: [geda-user] Apollon
From:	John Doty <jpd AT noqsi DOT com>
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Date:	Sun, 13 Sep 2015 13:31:57 -0600
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On Sep 13, 2015, at 12:24 PM, DJ Delorie <dj AT delorie DOT com> wrote:

> 
>> If you do this right, you wind up with *exact* knowledge of every
>> point in the x/y Cartesian geometry. Sines and cosines of these
>> angles are rational numbers. No roundoff error. You can choose any
>> unit basis you want (I'd go with meters).
> 
> I thought of this for arcs - define the endpoints and the radius, not
> the center and angles (there are other issues in this example, but
> still).  You're limited to what snaps to your grid, but if your grid
> is nanometers that's a very small error.
> 
> You do tend to go off-angle pretty quickly though, since so many
> angles result in irrational numbers.
> 

What I meant to say is that the rational number solution is gridless. It has a base unit, but you can have coordinates like 45634/1299709.

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd AT noqsi DOT com

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