Our choice, which indeed goes against several longer standing conventions
(like 0=East, +=counterclockwise, or 0 = N to 360 clockwise), was adopted
because we were looking for something that would be close to how a 7 year
old child thinks and had a symmetric use of positive, negative and 0 (the
original Etoys was for a younger age group). This has worked very well
and has many merits for all the ages of children we work with.
And, of course one can assign e.g. 245 to heading and the player will
point as expected.
I think the preference you suggest would be a good idea. There is already
one for all playfields (including the world desktop) as to whether (0,0)
should be in the lower left corner or the center of the rectangle ([]
origin at center). Both have their merits. Similarly, both negative
degrees and staying positive around the circle have their merits. And we
should probably (and likely will) put in a preference for the school math
system, now that we are starting to work with older children who are
somewhat thinking along those lines.
I think starting with other than 0 would be a bad idea (and would also
violate the compass convention). Similarly, school math starts with 0
pointing East, not 360.
If you want to see the regular compass headings you can write a simple
script that ticks once or twice a second that does the easy conversion
into a variable, then you can use a watcher to see the value on the
screen.
The debates we have are not about your issue but the more critical one of
whether we should have gone with the "school math" conventions
for more coherence later on. I still like starting with the compass with
N pointing up and clockwise for +. But there is a good QWERTY argument
for the school math conventions. (This gets more pernicious with older
children who have to learn the school convention -- and when vectors are
used -- should they be in school math or in compass?)
Cheers,
Alan
At 03:19 PM 5/25/2007, 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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http://www.nabble.com/Weird-Heading-numbers-tf3818581.html#a10811065
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