import numpy as np
import matplotlib.cm as cm

def map_to_color(a, range=None, map=cm.hsv):
    a = np.asarray(a)
    if range is None:
        range = (a.min(), a.max())

    ax = (a - range[0])/(range[1]-range[0])

    rgba = (map(ax)*255).astype(np.uint32)

    return rgba[:,0] << 16 | rgba[:,1] << 8 | rgba[:,2]