"Invalid dimensions for image data" error when creating a density plot of a function [duplicate]

Question

I keep receiving:

TypeError: Invalid dimensions for image data

with a blank graph that has axis going from 0.0 to 1.0 on both sides

import numpy as np  
import matplotlib.pyplot as plt  
from numpy import sin,cos,sqrt,arctan2  
from pylab import plot,show,xlabel,ylabel,linspace,ylim  

D = 50

x = linspace(0,D,1000)  
y = linspace(0,D,1000)

r1 = sqrt((x**2)+(y*2)) 

def function1():  
    f1 = sin(r1)  
    return f1  

function1()

plt.imshow(r1,origin='lower',extent=[0,10,0,5])  
plt.colorbar()  
plt.show()

seaotternerd · Accepted Answer · 2018-03-19 06:16:27Z

0

plt.imshow() is expecting to receive a two-dimensional array (i.e. one with an x and y axis), but r1 is one-dimensional (i.e. it is just a flat list of numbers). You can fix this with the reshape method of numpy arrays:

r1 = r1.reshape(10,100)

This will convert your list of 1000 numbers into 10 rows of 100 numbers. I arbitrarily chose 10 and 100 as a pair of numbers that multiply out to 1000. You should replace them with whatever you want the actual x and y dimensions of the image to be.

answered Mar 19, 2018 at 6:16

seaotternerd

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