ax1.set_xticks([int(j) for j in range(-4, 5)])
for label in (ax1.get_xticklabels() + ax1.get_yticklabels()):
    label.set_fontsize(15)
for tick in (ax1.get_xticklines() + ax1.get_yticklines()):
    tick.set_markeredgewidth(2)
tick.set_markersize(6)
im = ax1.imshow(velocity, cmap=cm.jet, interpolation='nearest', origin=
    'lower', vmin=0, vmax=1.7, extent=[-4.5, 4.5, 0, 3])
ax1.set_xlim(-4, 4)
divider = make_axes_locatable(ax1)
cax = divider.append_axes('right', size='2.5%', pad=0.3)
cb = plt.colorbar(im, cax=cax)
cb.set_label('Speed [$m/s$]')
plt.savefig('speed_400.png')
plt.close(fig)
Как ограничить диапазон оси x с помощью imshow()?