Hi,
that’s the Jet color map repeated back to back to make it cyclic. The scaling can be set by the user with the buttons in the top right, but by default it is 100mm for a single blue to red transition and starts with blue at z = 0mm.
It’s nice that you want to replicate the look of NxView, but please note that the Jet color map is not considered very good nowadays 
. There are more modern color maps available which are better perceptually and for color blind people, such e.g. the perceptually uniform color maps from matplotlib.