Re: [Matplotlib-users] Scaling the axis values from list indices to meaningful values

[Jae-Joon L. <lee...@gm...>]

use "extent" argument.

http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.imshow

-JJ


On Fri, Oct 2, 2009 at 7:21 PM, shamster <eri...@gm...> wrote:
>
> My current plot takes data to construct a 2d histogram. In gnuplot i would
> accomplish this by using splot, dgrid3d, and pulling in a 'matrix' data
> file. The code below has produced nearly what I need. However, the axes
> limits are set based on the indices of the incoming data (i.e. the number of
> rows or columns in my data matrix) instead of something meaningful. For
> example, my x-axis is set from 0 to 2000, but I'd like it to span from -1 to
> +1 because my x-data is a cosine function...
>
> I would imagine that some type of axis-scaling function would take a
> function to scale the labels... something akin to:
>
> scale_axis(lambda x: x*.001-1.0, ax)
>
> would do the trick of scaling my (0, 2000) data to the (-1.0, 1.0) extents.
> Is there any such functionality to actually scale the values of the axis
> tick-labels?
>
>
>
>
> <code snippet>
>
>  1 import sys
>  2 from scipy import *
>  3 import scipy.io.array_import
>  4
>  5 # plotting libs
>  6 import matplotlib.pyplot as plt
>  7 from pylab import *
>  8
>  9
>  10
>  11 file = scipy.io.array_import.read_array(sys.argv[1])
>  12 data = []
>  13
>  14 for i in range(len(file[0])):
>  15     data.append(file[:,i])
>  16
>  17 # create a figure
>  18 fig = figure(1)
>  19
>  20 cmBase = cm.jet   # choose a colormap to use for the plot
>  21
>  22 # This processes the data and adds the colored 2D histogram to the
> figure
>  23 im = imshow(data, interpolation='bilinear')
>  24 # A little magic to create a colorbar - legend for the plot
>  25 plt.colorbar(im)
>  26
>  27 # Turn on the X-Y grid
>  28 grid(True)
>  29
>  30 # Pass go - collect $200
>  31 draw()
>  32 show()
>
> </code snippet>
> --
> View this message in context: http://www.nabble.com/Scaling-the-axis-values-from-list-indices-to-meaningful-values-tp25724127p25724127.html
> Sent from the matplotlib - users mailing list archive at Nabble.com.
>
>
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