PREAMBLE: I have seen these, but I can't figure out from the answer how to do the plot. Also, I'm new with python and matplotlib.
I have a data file of the form
X Y Z
0.05 1 z
0.10 1 z
... ... ...
0.95 1 z
0.05 2 z
... ... ...
... ... ...
0.95 10 z
with z in [-0.02:0.5] for each of them. These results in 190 (x,y,z) points.
I acquire the data in this way
data_file = open('tau.txt', 'r')
buffer = data_file.read()
data_file.close()
data = [map(float, row.split('\t')) for row
buffer.strip().split("\n")]
As the link suggests, I convert them into a grid
mu = []
alpha = []
tau = []
for elements in data:
mu.append(elements[0])
alpha.append(elements[1])
tau.append(elements[2])
x_data = np.asarray(mu)
y_data = np.asarray(alpha)
z_data = np.asarray(tau)
xi = np.linspace(0.05,0.95,19)
yi = np.linspace(1,10,10)
ar = griddata(x_data,y_data,z_data,xi,yi,interp='nn')
Then I do the plot: I would like this so that each (x,y) co-ordinate has a square centered on the co-ordinate, with a colorbar showing the z value.
cmap = mpl.colors.LinearSegmentedColormap.from_list('my_colormap',
['white','grey','black'],256)
img = plt.imshow(ar,interpolation='nearest',cmap =
cmap,origin='lower')
plt.colorbar(img,cmap=cmap)
I obtain this:
First of all, I want the colourbar to be of the same height of the plot itself. I can't understand how to avoid this trash.
Moreover, if you look at the file you immediately see that ranges are not right: x has to be in [0.05:0.95] and y in [1:10]. y is simply shifted of 1 (the white lines, with all z=0 should be for y=1 and not y=0), while x assumes values I can't understand.
I this is important to note that except for these, the plot is right, both in the z values and in the trend.
How can I fix my problem(s)?
