[Squeakland] Weird Heading numbers

Paulo Drummond ptdrumm at terra.com.br
Fri May 25 21:21:16 PDT 2007


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 at terra.com.br>
>> To: mstram <mstramba at sympatico.ca>
>> CC: squeakland at 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:
>> 1) 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   
>> 359º59'59" 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
>>> --
>>> View this message in context: http://www.nabble.com/Weird- 
>>> Heading- numbers-tf3818581.html#a10811065
>>> Sent from the SqueakLand mailing list archive at Nabble.com.
>>>
>>> _______________________________________________
>>> Squeakland mailing list
>>> Squeakland at squeakland.org
>>> http://squeakland.org/mailman/listinfo/squeakland
>>>
>
>
>




More information about the Squeakland mailing list