[FIXED] Streamplot mismatch colorbar ticks

Issue

Anyone knows why this ocurrs in colobar ticks? How to fix it?

The code:

ax = plt.axes(projection=ccrs.PlateCarree())
cf3 = ax.streamplot(u.longitude, u.latitude, u.isel(valid_time=index).data, 
                        v.isel(valid_time=index).data, linewidth=0.5, cmap=plt.cm.jet, 
                        arrowsize=1.5, density=5, color=mag, transform=ccrs.PlateCarree())
axins = inset_axes(ax, width="95%", height="2%", loc='lower center', borderpad=-3.6)
bar = fig.colorbar(cf3.lines, cax=axins, orientation='horizontal', extendrect=True, label='Velocidade [m/s]')
cbar.set_ticks(ticks=[0,5,10,15,25,30])

Solution

With the limited code provided, I think passing the 'norm' argument to ax.streamplot() could solve your issue. First you need to create a normalized object using:

import matplotlib as mpl
normalize = mpl.colors.Normalize(vmin, vmax)

Where 'vmin' and 'vmax' correspond to your desired upper and lower limits of the values used for the colorbar.

For example:

normalize = mpl.colors.Normalize(0, 40)
cf3 = ax.streamplot(u.longitude, u.latitude, u.isel(valid_time=index).data, 
                    v.isel(valid_time=index).data, linewidth=0.5, cmap=plt.cm.jet, 
                    arrowsize=1.5, density=5, color=mag, transform=ccrs.PlateCarree(),norm=normalize)

should limit your colorbar values between 0 and 40, leading to identical colorbars between iterations of your streamplots.

Answered By - Spencejo