Re: What are the proper terms for these concepts?
On 3/13/12 8:17 PM, John B. Matthews wrote:
In article<ncO7r.46319$Bp4.19988@newsfe14.iad>,
Daniel Pitts<newsgroup.nospam@virtualinfinity.net> wrote:
On 3/13/12 11:25 AM, Lew wrote:
[...]
The term "bearing" comes to mind, and I recall "absolute" vs. "relative" -
let me double check.
http://en.wikipedia.org/wiki/Bearing_(navigation)
http://en.wikipedia.org/wiki/Relative_bearing
http://en.wikipedia.org/wiki/Absolute_bearing
The term "bearing" matches what you want as the augend. The addend
you want is "angle".
So you add an angle to a bearing to get a new bearing.
Ah, that actually makes a lot of sense, and generally that matches
the use of the value. It is use for things such as the heading of a
robot, missile, or other simulated item.
It may also be important to distinguish between mathematical (counter-
clockwise from the positive x-axis) and navigational (clockwise from the
positive y-axis) conventions, as suggested in this example:
<http://stackoverflow.com/a/3467341/230513>
This is actually why I use the abstractions I do, there are no
constructors for AbsoluteAngle or RelativeAngle, only factory methods
clockwiseRadians, counterClockwiseRadians, etc...
The simulated robots do have a different convention (it may be somewhat
standard navigational). They don't use standard units though, they use a
single unsigned byte to represent angle: 0 is NORTH, 64 is EAST, 128 is
SOUTH, 192 is WEST. In my code, I call this "bygrees" (byte-degrees).