matplotlib-users Mailing List for matplotlib

hello,
I would like to plot in 3D a dataset organized as 1000 x,y,z points in a 
numpy array, so it would be smthg like 
plot3d(data[:,0],data[:,1],data[:,2]). I looked at the plot3D cookbook 
page, but it all seems to expect some sort of binning on a grid.....

best,
Johann

Hi all
I am new to the interactive matplotlib scripting. I need to get coordinate
list of some pixels interactively from the image.
My aim is to get the coordinate list of some region first by selecting
interactively. If I could select the region successfully, then using a key
press (say 'a' key) save that list. If the selection is bad then I want to
ignore the list using a key press (say, 'c' key) and go for the next
selection. When I finish the selection quit the interactive mode by using
another key press (say, 'q').
I tried to modify the lasso_demo.py but failed to achieve the task. I am
attaching the code. Could anybody help me?
Thanks
Vinu V

#!/usr/bin/env python
"""
Show how to use a lasso to select a set of points and get the indices
of the selected points.  A callback is used to change the color of the
selected points

This is currently a proof-of-concept implementation (though it is
usable as is).  There will be some refinement of the API and the
inside polygon detection routine.
"""
from matplotlib.widgets import Lasso
import matplotlib.mlab
from matplotlib.nxutils import points_inside_poly
from matplotlib.colors import colorConverter
from matplotlib.collections import RegularPolyCollection
import pyfits
import pylab
from pylab import figure, show, nx
import numpy as n
from matplotlib.patches import Polygon

class LassoManager:
    def __init__(self, ax, x, y, z):
        self.axes = ax
        self.canvas = ax.figure.canvas
        self.x = x
        self.y = y
        self.z = z
        ax.contourf(x,y,z, 50)
        x1 = n.reshape(x, (size * size, 1))
        y1 = n.reshape(y, (size * size, 1))
        self.xy = n.concatenate((x1,y1),axis=1)
        self.Nxy = size * size
        self.cid = self.canvas.mpl_connect('button_press_event',
self.onpress)
        self.cid2 = fig.canvas.mpl_connect('key_press_event', self.onpress1)
    def onpress1(self, event):
        if event.key=='a':
            accept = 'yes'
            print accept
        if event.key=='c':
            accept = 'no'
            print accept
        elif event.key=='q':
            pylab.close()
    def callback(self, verts):
        ind = nx.nonzero(points_inside_poly(self.xy, verts))
        print ind % size, ind / size
        for i in range(self.Nxy):
            if i in ind:
                pass
            else:
                pass
        rect = Polygon(verts, facecolor='red', alpha=0.3)
        self.axes.add_patch(rect)
        self.canvas.draw_idle()
    def onpress(self, event):
        self.lasso = Lasso(event.inaxes, (event.xdata, event.ydata),
self.callback)


f = pyfits.open('I_EDCSNJ1216453-1201176.fits')
z = f[0].data
f.close()
size = z.shape[0]
x = n.reshape(n.arange(size * size), (size, size)) % size
x = x.astype(n.float32)
y = n.reshape(n.arange(size * size), (size, size)) / size
y = y.astype(n.float32)
fig = figure()
ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
lman = LassoManager(ax, x, y, z)
show()


-- 
VINU VIKRAM
http://iucaa.ernet.in/~vvinuv/

Jim Vickroy wrote:
>Thanks for the detailed explanation; I may be starting to understand =
the=20
>significance of *figure*.

>I was hoping to avoid repeated calls like map.drawcoastlines(),=20
>map.drawcountries(), map.fillcontinents(color=3D'0.95'),=20
>map.drawmapboundary(), map.drawmeridians(plot.arange(0,360,30)), and=20
>map.drawparallels(plot.arange(-90,90,30)).  So, I will follow your=20
>example and experiment to see what works and what does not to better=20
>understand the behaviors.

Hi Jim and others,

You should definitely reuse the basemap instance but from your reply it =
seems like you would also like to reuse the figure instance. The current =
figure instance is changed when you make plot commands like =
map.drawcountries(). What I do is to remove the stuff that should not be =
reused. That is something like this:

# If first time create figure from basemap using my function getfigure
if fig =3D=3D None:
  fig =3D getfigure(map)

# The figure I am plotting on has two axes which I change - an axes with =
the plot and an axes with a colorbar
ax =3D fig.get_axes()[0]
cax =3D fig.get_axes()[1]

# Create plot and save figure
cs =3D map.contourf(lon, lat, data, ax=3Dax)
fig.colorbar(cs, cax=3Dcax, orientation=3D'vertical', extend=3D'both')
fig.savefig(filename)

# Remove contourf axes ContourSets
for c in cs.collections:
  ax.collections.remove(c)

# Remove colorbar axes ContourSets
cax.collections =3D []

Hope it helps.

Regards,
Jesper