On 2014/03/01 11:03 AM, ChaoYue wrote: > The most correct way might be to design a new colormap with white color > exactly in the middle, however this is very tedious, especially if I > want to try > different colormaps. so the alternative approach would be to set the values > falling in (-1,1) as being masked, so they will be the same as the axes > background color as you mentioned (in our case it's white). My question is, > how can I put this background color (which shows maksed data) in the > colorbar, > by avoiding design a new colormap?
It's not the answer you want to hear, but I think the correct answer is that you should do this via the colormap, and not by masking the low values. It doesn't have to be painful. If, in contourf, you use a diverging colormap with white already in the middle (http://matplotlib.org/examples/color/colormaps_reference.html) and a norm with symmetric limits (vmin and vmax; you can let them be set automatically after you specify your symmetric set of contour boundaries appropriately) then it will be done for you. e.g., z = 10 * np.random.randn(20, 30) clevs = [-10, -5, -2, -1, 1, 2, 5, 10] cs = plt.contourf(z, levels=clevs, cmap=plt.get_cmap('PRGn'), extend='both') cbar = plt.colorbar(cs, spacing='uniform') Eric ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. Cisco certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer Customize your own dashboards, set traffic alerts and generate reports. Network behavioral analysis & security monitoring. All-in-one tool. http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
