Thread: [Matplotlib-users] How to get the value of a cell in pcolormesh

Hi everyone!
It is cool to use the pcolormesh in matplotlib. However, is there a way to
get the i, j indexes of the clicked cell? I have try event.mouseevent.xdata
and event.mouseevent.x. But they did not return the index I need.
Thanks in advanced for your help.
Dr. Jiacong Huang
Nanjing Institute of Geography & Limnology
Chinese Academy of Sciences
73 East Beijing Road, Nanjing 210008, China
Tel./Fax: +86-25-86882127
Homepage: http://www.escience.cn/people/elake/index.html
---Code to generate pcolormesh-------------------------------
import numpy as np
from matplotlib.pyplot import figure, show
from numpy import ma
n = 12
x = np.linspace(-1.5,1.5,n)
y = np.linspace(-1.5,1.5,n*2)
X,Y = np.meshgrid(x,y);
Qx = np.cos(Y) - np.cos(X)
Qz = np.sin(Y) + np.sin(X)
Qx = (Qx + 1.1)
Z = np.sqrt(X**2 + Y**2)/5;
Z = (Z - Z.min()) / (Z.max() - Z.min())
# The color array can include masked values:
Zm = ma.masked_where(np.fabs(Z) > 100, Z)
fig = figure()
ax = fig.add_subplot(111)
col = ax.pcolormesh(Qx[:5,:4],Qz[:5,:4],Zm[:4,:3])
show()
-------------------------
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To get the index of the grid you clicked on requires some knowledge of what
artist you are working with.
See https://github.com/matplotlib/matplotlib/pull/3989 for some brand new
code which makes this easier to implement in a general way.
While we catch up with that you will need to implement your own mapping of
x/y in data space -> i, j See
http://matplotlib.org/examples/api/image_zcoord.html for an example.
Tom
On Tue, May 12, 2015 at 2:21 AM GoogleWind <goo...@16...> wrote:
> Hi everyone!
> It is cool to use the pcolormesh in matplotlib. However, is there a way to
> get the i, j indexes of the clicked cell? I have try
> event.mouseevent.xdata
> and event.mouseevent.x. But they did not return the index I need.
>
> Thanks in advanced for your help.
>
> Dr. Jiacong Huang
> Nanjing Institute of Geography & Limnology
> Chinese Academy of Sciences
> 73 East Beijing Road, Nanjing 210008, China
> Tel./Fax: +86-25-86882127
> Homepage: http://www.escience.cn/people/elake/index.html
>
>
>
> ---Code to generate pcolormesh-------------------------------
> import numpy as np
> from matplotlib.pyplot import figure, show
> from numpy import ma
>
> n = 12
> x = np.linspace(-1.5,1.5,n)
> y = np.linspace(-1.5,1.5,n*2)
> X,Y = np.meshgrid(x,y);
> Qx = np.cos(Y) - np.cos(X)
> Qz = np.sin(Y) + np.sin(X)
> Qx = (Qx + 1.1)
> Z = np.sqrt(X**2 + Y**2)/5;
> Z = (Z - Z.min()) / (Z.max() - Z.min())
>
> # The color array can include masked values:
> Zm = ma.masked_where(np.fabs(Z) > 100, Z)
>
> fig = figure()
> ax = fig.add_subplot(111)
> col = ax.pcolormesh(Qx[:5,:4],Qz[:5,:4],Zm[:4,:3])
> show()
> -------------------------
>
>
>
> --
> View this message in context:
> http://matplotlib.1069221.n5.nabble.com/How-to-get-the-value-of-a-cell-in-pcolormesh-tp45499.html
> Sent from the matplotlib - users mailing list archive at Nabble.com.
>
>
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Hi Tom,
It is nice to receive your hints. I would like to try it.
Best regards,
Jiacong Huang
--
View this message in context: http://matplotlib.1069221.n5.nabble.com/How-to-get-the-value-of-a-cell-in-pcolormesh-tp45499p45610.html
Sent from the matplotlib - users mailing list archive at Nabble.com.