matplotlib pcolormesh plot from x,y,z data

Question

I have data in a textfile in tableform with three columns. I use np.genfromtxt to read all the columns into matplotlib as x, y, z.

I want to create a color meshplot where x and y are the coordinates and z represents the color, i think people refer to such a plot as heatmap.

My code is as follows:

x = np.genfromtxt('mesh.txt', dtype=float, delimiter=' ', usecols = (0))
y = np.genfromtxt('mesh.txt', dtype=float, delimiter=' ', usecols = (1))
z = np.genfromtxt('mesh.txt', dtype=float, delimiter=' ', usecols = (2))

xmesh, ymesh = np.meshgrid(x,y)
diagram1.pcolormesh(xmesh,ymesh,z)   

But I get the following error message:

line 7154, in pcolormesh
C = ma.ravel(C[0:Ny-1, 0:Nx-1]) # data point in each cell is value at
IndexError: too many indices

The textfile is as follows:

1 1 5
2 1 4
3 1 2
4 1 6
1 2 6
2 2 2
3 2 1
4 2 9
1 3 7
2 3 4
3 3 3
4 3 5
1 4 3
2 4 4
3 4 7
4 4 6

How is this to solve.

Answer 1

In the example data provided above, x, y, and z can be easily reshaped to get 2D array. The answer below is for someone who is looking for more generalized answer with random x,y, and z arrays.

import matplotlib.pyplot as plt
from matplotlib.mlab import griddata
import numpy

# use your x,y and z arrays here
x = numpy.random.randint(1,30, 50)
y = numpy.random.randint(1,30, 50)
z = numpy.random.randint(1,30, 50)

yy, xx = numpy.meshgrid(y,x)
zz = griddata(x,y,z,xx,yy, interp='linear')
plt.pcolor(zz)
#plt.contourf(xx,yy,zz) # if you want contour plot
#plt.imshow(zz)
plt.pcolorbar()
plt.show()