[Matplotlib-users] Plotting dates on the y-axis of a contour map/ hovmoller

[Paul Hobson]

The contour function can be called in many forms.

Without your data, it's hard to see exactly what's going on, but it looks
like you're using the contour(Z, V) form.

I recommend using the contour(X, Y, Z) form. Passing Y as an array of
datetime-like object should "just work".

If it doesn't, boil this example down to something we can copy-paste into a
terminal/notebook and mess around with. A 5 x 5 array for your Z values and
some of the dates in the format you currently have them should suffice.
-Paul

On Mon, Jul 10, 2017 at 12:26 PM, vaultron94 <sbuechele at albany.edu> wrote:

> Hello all,
>
> So I ran into a snare when making a Hovmoller for a case study. I have
> everything done and colors picked out. But for the life of me cannot find a
> way to get the Y-axis to plot the dates provided in the data. Here is the
> script I have.
>
> import numpy as np
> import datetime
> import matplotlib.pyplot as plt
> import os
> import pandas as pd
>
> def cmap(cmap):
>     cmap = plt.cm.get_cmap(cmap)
>
> data = pd.read_excel('/Users/operator/Documents/Hovmoller_dewpt.xlsx')
>
> a=np.array(data)
>
> time= (a[:,0])
> lat= (a[:,1])
> lon= (a[:,2])
> BATA= (a[:,3])
> BSPA= (a[:,4])
> BUFF= (a[:,5])
> CLIF= (a[:,6])
> FAYE= (a[:,7])
> HERK= (a[:,8])
> JOHN= (a[:,9])
> JORD= (a[:,10])
> OPPE= (a[:,11])
> WEST= (a[:,12])
> timeZ= (a[:,13])
>
>
> b=np.vstack((BUFF,BATA,CLIF,JORD,FAYE,WEST,HERK,OPPE,JOHN,BSPA)).T
>
> plt.contourf(b, np.arange(40,67), cmap=('jet'))
>
>
> plt.xlabel('BUFF  BATA  CLIF  JORD  FAYE  WEST  HERK  OPPE  JOHN  BSPA')
> plt.ylabel('Time')
> plt.grid('off')
> plt.colorbar()
>
> plt.title('Dewpoint Hovmoller for Mesonet Sites')
> plt.figure()
>
> #timeZ contains the dates I want, and instead of having the number of rows
> as the y axis I want the dates there instead. Attached is the graphic I get
> as of now. Any thoughts or advice is much appreciated!
>
> Thank you
>
> <http://matplotlib.1069221.n5.nabble.com/file/n48081/DewPoint.png>
>
>
>
> --
> View this message in context: http://matplotlib.1069221.n5.
> nabble.com/Plotting-dates-on-the-y-axis-of-a-contour-map-
> hovmoller-tp48081.html
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