How to obtain samples within angular windows?

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OH 2017-1-17

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评论： OH 2017-1-21

Hi, Let us say I have a projectile moving around in a square environment and I want to sample all positions where the projectile has travelled within a 20 degrees angular window, as seen from a fixed point in the environment. Can anyone help me figure out how to do this? In the attached picture, the spiral is a made up path of the projectile and the red dot is the fixed point from which I want to make the angular window.

Thanks

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OH 2017-1-18

Ok, so if I construct vectors with 20 degrees separation emanating from the fixed point (as in the picture below), can I then somehow get all the non-NaN elements (i.e where the projectile has been) in the area between two vectors?

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Answer 1

Jyotish Robin 2017-1-20

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Hi,

Since you are asking for a way in which you can get the non- NaN elements, I suppose you are having a matrix which corresponds to the image. Let me know if that is not the case.

Now, I would suggest you to make use of the function "isnan". isnan(A) returns an array with the same size as A containing logical 1 (true) where the elements of A are NaNs and logical 0 (false) where they are not.

So if it's just a 1D vector ( say y), you can simply do something like this:

>>y1 = y(~isnan(y));

You can read about this in detail in the below link:

https://www.mathworks.com/help/matlab/ref/isnan.html

Hope it helps!!