On May 25, 2007, at 11:57 PM, Mike Stramba wrote:
Compasses, GPS, Aircraft, Marine Vessels all use "real headings".
Ok. Try explain to a 8-year child that 0 = 360.
I've never heard of any other use for them (before playing with Etoys ;) )
It's Geometry, in its very roots. I bet starting with this negativity of angles, relativity of things, one who learned with this principles in mind can understand the real basic Geometry (Euclidian, Cartesian, Vector Space etc) much better, much earlier.
cheers, Paulo
Mike
From: Paulo Drummond ptdrumm@terra.com.br To: mstram mstramba@sympatico.ca CC: squeakland@squeakland.org Subject: Re: [Squeakland] Weird Heading numbers Date: Fri, 25 May 2007 23:50:47 -0300
Imho, there is no such thing as "real headings". Geometry, as its mother Mathematics is a wonderful symbolical language to provide us all means of mapping the physical world as we see it.
The use of semi-circular geometrical convention helps (among other things) in:
- give the sense of "negative" when the object passes "downward"
or "to the other side" of an 2-D axis (another convention); 2) the coming back rationally to zero instead of jumping from 359ยบ59'59" to it.
cheers, Paulo
On May 25, 2007, at 7:19 PM, mstram wrote:
While playing with the Etoys, I've noticed the "weird" heading numbers.
By that I mean when the object's heading passes 180 degrees, instead of continuing on to 190 ... 270 .. 360, we get the negative numbers.
Why was this convention adopted ?
I think if kids ... and some us "older" kids are going to be using headings it would be more educational and instructive to use "real" headings.
Maybe an option / preference could be setup on which heading numbering system to use.
The only minor problem I can see is whether it should be "0" or "360" to begin with.
Just for the fun of it, I'm digging in and seeing if I can construct my own subclass to use the "360" system. I have an idea for an ATC simulation I'd like to do and "real" headings .. or at least converted for input and output would be a must.
Mike
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