Hi Gökhan,
On Friday 17 April 2009 20:21:00 Gökhan SEVER wrote:
> Thanks for the pointer Matthias,
>
> That is exactly what I have been looking for.
>
> I use the code from the RectangleSelector class help with your suggested
> code. I know that I have to update y-axis accordingly to x values such that
> their positions and sizes must much so that I can plot them in a new plot.
> And I know that the answer lies in a mask; I have to create a mask from
> x_new and apply it to y. Do you have any hint on this?
Unfortunately I'm not familiar with numpy masks, but what I would do is:
xmin = min(eclick.xdata, erelease.xdata)
xmax = max(eclick.xdata, erelease.xdata)
ymin = min(eclick.ydata, erelease.ydata)
ymax = max(eclick.ydata, erelease.ydata)
# indices inside x-range
indices = (x>= xmin) & (x <= xmax)
# OR: indices for data inside the selected rectangle
#indices = (x>= xmin) & (x <= xmax) & (y>=ymin) & (y<=ymax)
xnew = x[indices]
ynew = y[indices]
> Another point is do you have any idea how to save values from inside
> onselect action?
What do you mean by saving?
Saving to disk?
# for ascii format I use:
from scipy.io import write_array
# for numpy arrays you can use
import numpy as np
a = np.arange(10)
a.tofile # Write array to a file as text or binary.
and I think there is also some Matplotlib function for this. In the module
matplotlib.mlab, which also allows reading different types of formatted data.
If you think of saving inside the program. You need a global variable
(statement "global x" at the beginning of onselect) otherwise all variables
are deleted at the end of each onselect call.
> For some reason my ipython session doesn't remember values after I run the
> given script:
see three lines above, please.
best regards Matthias
>
> from matplotlib.widgets import RectangleSelector
> from pylab import *
>
> def onselect(eclick, erelease):
> # eclick and erelease are matplotlib events at press and release
> print ' startposition : (%f, %f)' % (eclick.xdata, eclick.ydata)
> print ' endposition : (%f, %f)' % (erelease.xdata, erelease.ydata)
> print ' used button : ', eclick.button
> xmin = min(eclick.xdata, erelease.xdata)
> xmax = max(eclick.xdata, erelease.xdata)
> ymin = min(eclick.ydata, erelease.ydata)
> ymax = max(eclick.ydata, erelease.ydata)
> x_new = x[(x>= xmin) & (x <= xmax)]
> #mask = [x == x_new[i] for i in range(len(x_new))]
> #print mask
> #print len(x_new)
> #print len(y_new)
> #fig_new = figure()
> #plot(x_new, y_new)
> #fig_new.show()
>
> def toggle_selector(event):
> print ' Key pressed.'
> if event.key in ['Q', 'q'] and toggle_selector.RS.active:
> print ' RectangleSelector deactivated.'
> toggle_selector.RS.set_active(False)
> if event.key in ['A', 'a'] and not toggle_selector.RS.active:
> print ' RectangleSelector activated.'
> toggle_selector.RS.set_active(True)
>
> x = arange(100)/(99.0)
> y = sin(x)
> fig = figure
> ax = subplot(111)
> ax.plot(x,y)
>
> toggle_selector.RS = RectangleSelector(ax, onselect, drawtype='box')
> connect('key_press_event', toggle_selector)
> show()
>
> Gökhan
>
>
> On Fri, Apr 17, 2009 at 2:31 AM, Matthias Michler
>
> <matthiasmich...@gmx.net>wrote:
> > Hi Gökhan,
> >
> > I recommend you to use matplotlib.widgets.RectangleSelector instead of
> > the zoom functionality to select the data (An example can be found at
> > http://matplotlib.sourceforge.net/examples/widgets/rectangle_selector.htm
> >l). This will return you the x and y-coordinate of button press and button
> > release
> > event and with that you can take a portion of your data.
> > Something like the following could be a starting point:
> > x_min = min(eclick.xdata, erelease.xdata)
> > x_max = max(eclick.xdata, erelease.xdata)
> > x_new = x[(x>= x_min) & (x <= x_max)]
> >
> > where eclick and erelease correspond to the click and release event of
> > the rectangle selection (see the example below).
> >
> > Opening a new figure after show can be achieved by:
> >
> > fig_new = plt.figure()
> > # some plotting
> > fig_new.show() # show up the new figure
> >
> >
> > best regards Matthias
> >
> >
> > yet another example for the usage of the RectangleSelector copied from
> > its class documentation:
> >
> > """
> > Select a min/max range of the x axes for a matplotlib Axes
> >
> > Example usage::
> >
> > from matplotlib.widgets import RectangleSelector
> > from pylab import *
> >
> > def onselect(eclick, erelease):
> > 'eclick and erelease are matplotlib events at press and release'
> > print ' startposition : (%f, %f)' % (eclick.xdata, eclick.ydata)
> > print ' endposition : (%f, %f)' % (erelease.xdata,
> > erelease.ydata)
> > print ' used button : ', eclick.button
> >
> > def toggle_selector(event):
> > print ' Key pressed.'
> > if event.key in ['Q', 'q'] and toggle_selector.RS.active:
> > print ' RectangleSelector deactivated.'
> > toggle_selector.RS.set_active(False)
> > if event.key in ['A', 'a'] and not toggle_selector.RS.active:
> > print ' RectangleSelector activated.'
> > toggle_selector.RS.set_active(True)
> >
> > x = arange(100)/(99.0)
> > y = sin(x)
> > fig = figure
> > ax = subplot(111)
> > ax.plot(x,y)
> >
> > toggle_selector.RS = RectangleSelector(ax, onselect,
> > drawtype='line')
> > connect('key_press_event', toggle_selector)
> > show()
> > """
> >
> > On Friday 17 April 2009 02:26:51 Gökhan SEVER wrote:
> > > Hello,
> > >
> > > A quick question:
> > >
> > > I am using two numpy arrays to plot the figure shown in attachment. Is
> > > it possible to get array indices of selected X-axes while using the
> > > zoom function? Later I can create a new figure from this selected
> > > portion instead of the same figure and/or apply an analysis.
> > >
> > > Thank you.
> >
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