atand and atan2d

I have some motion capture data and I have calculated the vertical angles that participants used when wielding an object (atand(y/x)).

The issue is that if they exceed 90 degrees, atand freaks out.

I want to convert to atan2d to avoid this issue.

So I've been playing with it a bit and here is where I'm at. https://imgur.com/a/gxv8DW5

The red line is atand and the blue line is atan2d.

red = atand(y/x)

blue = atan2d(y,x)

Not sure how to handle these values. The output from atand are the correct angle participants used, how can I get atan2d to output the correct angles, but also capture values outside of the -90:90 degree limit of atand.

Answer 1

[Star Strider]

I am not certain what result you want.

Try these utility functions I created for my own use a while ago:

Angles360 = @(a) rem(360+a, 360);                        % For ‘atan2d’
Angles360a = @(a) rem(180+a, 540);                       % Maps: [-180,180] —> [0,360]
Result1 = Angles360([-150 180])
Result2 = Angles360a([-150 180])

[Corey Magaldino]

I'm trying something similar with the unwrap command that has been working okay.

If I do unwrap(blue) and then add 180 degrees, they seem to overlap with some slight issues at the point of the unwrap. I'll try this out, thanks!

[Star Strider]

My pleasure.

The unwrap function is intended to provide continuityfor (typically phase) angles that would otherwise repeat on modulo pi or 180°. My functions map one continuous angle to [0,360], and do not unwrap them.

If my Answer helped you solve your problem, please Accept it!

Please do not close Questions that have Answers.

Answer 2

[madhan ravi]

Just a guess try:

blue = atan2d(y/x,x)