How are Y coordinates actually mean to be interpreted?

[anselanza]

In the BlazePoseRenderer.py file, there is a curious comment block:

Beware, the y value of landmarks_world coordinates is negative for landmarks 
above the mid hips (like shoulders) and negative for landmarks below (like feet).
The y value of (x,y,z) coordinates given by depth sensor is negative in the lower part
 of the image and positive in the upper part.

Is there in fact a mistake in the first sentence?

Surely it is not possible for the Y values to be negative BOTH for landmarks above AND below the mid hips?

Should the sentence not read something like (change in bold):

the y value of landmarks_world coordinates is negative for landmarks above the mid hips (like shoulders) and positive for landmarks below (like feet)

This is important, because I'm trying to translate the landmark points to absolute positions in the same way in my own project, and this "explanation" made no sense to me.

[anselanza]

There is a comment at https://discuss.luxonis.com/d/5006-how-are-landmark-coordinates-really-meant-to-be-translated which simply states that "yes it is a typo", but still doesn't answer the question of which direction is positive and which is negative, relative to the "mid hips".