Matplotlib imshow() too many objects for cmap

Question

I'm trying to create a simple imshow() plot (matplotlib v.1.2.1) of a 2D gaussian function: ``` import matplotlib.pyplot as plt import numpy as np from pylab import * def gaussian(x,y,stdx,stdy): return 1.0/(2*np.pi*stdx*stdy) * (np.exp(-0.5*(x**2/stdx**2 + y**2/stdy**2))) coords = np.linspace(-1,1,100) X,Y = np.meshgrid(coords,coords) std_list = np.linspace(1,2,20) output = [gaussian(X,Y,std_list[i],std_list[i]) for i in range(len(std_list))] for i in range(len(output)): plt.imshow(X,Y,np.array(output[i]),cmap='bone') plt.show() ``` And I get the following error: ``` Traceback (most recent call last): File "blur.py", line 14, in plt.imshow(X,Y,np.array(output[i]),cmap='bone') TypeError: imshow() got multiple values for keyword argument 'cmap' ``` In fact, to make sure I wasn't crazy, I took out the cmap argument altogether, and now I'm getting the following error: ``` Traceback (most recent call last): File "blur.py", line 14, in plt.imshow(X,Y,np.array(output[i]))…

Accepted Answer

`imshow` doesn't take `x`, `y`, `z` as input. (`pcolor` and `pcolormesh` do, however).

Either use `pcolormesh(x, y, z)`, or use the `extent` kwarg to imshow.

e.g.

```
plt.imshow(Z, extent=[X.min(), X.max(), Y.min(), Y.max()],
           cmap='bone')
```

or

```
plt.pcolormesh(X, Y, Z, cmap='bone')
```

What's happening is that `imshow` expects

```
imshow(X, cmap=None, norm=None, aspect=None, interpolation=None,
         alpha=None, vmin=None, vmax=None, origin=None, extent=None,
         **kwargs)
```

Notice that the second argument is `cmap`, which explains why you're getting the error you are when you pass in an additional `cmap` kwarg.

Hopefully that clarifies things a touch! Good luck!

Matplotlib imshow() too many objects for cmap

Solution

Problem