How to limit the range of the x-axis with imshow()?

Question

I have the following data ``` 1.105 0.919 0.842 0.715 0.704 0.752 0.827 1.049 0.584 0.998 0.931 0.816 0.787 0.803 0.856 0.782 0.872 0.710 1.268 1.189 1.036 0.984 0.847 0.948 1.083 0.864 0.792 ``` that I plot with `imshow()` The result looks like this: Here is my code: ``` from numpy import* import matplotlib.cm as cm import matplotlib.mlab as mlab import matplotlib.pyplot as plt from mpl_toolkits.axes_grid1 import make_axes_locatable shape=(3,9) velocity=zeros(shape) fig = plt.figure(figsize=(16, 12), dpi=100) ax1 = fig.add_subplot(111,aspect='equal') # ax1.set_yticks([int(100*j) for j in range(0,4)]) ax1.set_yticks([int(j) for j in range(0,4)]) 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) ax1.set_aspect("equal") velocity=loadtxt("fieldvelocitybot-300-100-100_400.dat") im = plt.imshow(velocity, c…

Accepted Answer

Setting the extent for imshow is good, since this defines the range of your data. It does not specify the range of what is shown, because this is a property of the axes and can be set by simply adding ax1.set_xlim(-4,4)

So:

```
from mpl_toolkits.axes_grid1 import make_axes_locatable
import numpy as np
import matplotlib.pyplot as plt

velocity=np.random.rand(3,9)

fig, ax1 = plt.subplots(1,1,figsize=(16, 12), dpi=100, subplot_kw={'aspect': 'equal'})

ax1.set_yticks([int(j) for j in range(0,4)])
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=[-4.50,4.50,0,3])
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)
```

How to limit the range of the x-axis with imshow()?

Solution

Problem