Apply HSV colorscale with 180 degree repetition

Hi

I'm having a NxMxL matrix, where each of the L NxM matrices represent regions with different orientations (in real space), each region can only have 1 orientation(the value of that index is 1 if that index have is oriented in that direction, 0 if not) so if I sum over L the resulting NxM matrix will have 1 in every index. The directions have 180 degree invariance.

What i want to do then, is to have an NxM matrix and show a picture of it where it can be easily seen which regions have different orientations when comparing with a unity circle where the angle in the unity circle is the orientation direction. So first off i need help making that unity circle. Preferably just make 1 circle with "continous" color scale and refer to that for every time i do my script.

Obviously I want to use HSV color scale since it repeats itself.

What i have done: I have L possible orientations between 0 and 179 degrees. And mutiply each NxM matrix with cos(angle of that orientation)and then sum up the matrices, and then view the matrix using imagesc and then swap to HSV colormap trying to change the scaling range [0,1] to [-1,1]. I haven't added any code because I think it's very very wrong.

Can add i'm not too familiar with the plotting libraries in matlab.