Modify values so all have the same relative scale for differences.

    Using the chosen base heights, adjusts an individual sub-plot to be consistent
    relative to that height.

def get_floor_value(x, cat, vartype, floors):
    """Modify values so all have the same relative scale for differences.

    Using the chosen base heights, adjusts an individual sub-plot to be consistent
    relative to that height.
    """
    all_base = floors[vartype]
    cur_max = floors[(cat, vartype)]
    if cur_max > all_base:
        diff = cur_max - all_base
        x = max(1, x - diff)
    return x