I need to force the "rounding" of x axis limits

Community matplotlib-users
1

INTRO

···

=====

please consider the following code (I'm trying to draw a timeline)

1 from matplotlib import pyplot, patches
2 fig = pyplot.figure()
3 ax = fig.add_subplot('111')
4 ax.add_patch(patches.Rectangle((1933,0.25), 73, 0.5))
5 pyplot.show()

that gives me a plot with the x axis that goes from 0.0 to 1.0,
now consider

  ...
5 ax.set_xlim((1933,1933+73))
6 pyplot.show()

this gives me an x axis that goes _exactly_ from 1933 to 2006,
eventually drawing a line superposed to the lower spine

  ...
5 ax.plot((1933,1933+73),(0,0))
6 pyplot.show()

gives me what I really want, that is an x axis running from 1930 to
2010, with the limits automatically rounded by matplotlib...

(I noted that the extra line forces a rounding also for the y axis
limits, but that's not a problem...)

QUESTION

I want matplotlib to round the limits of the x axis automatically,
when given explicitly the lower and upper limits of the data, how to?

Thank you in advance

--
"We have met the enemy and he is us."
                                                        --- Pogo.

2

I am not really sure what you mean by ‘round’. Do you want to suppress the offset or do you want mpl to pick ‘nice’ values after you have explicitly set the limits?

Tom

···

On Mon, Apr 6, 2015 at 5:27 AM giacomo boffi <giacomo.boffi@…287…> wrote:

INTRO

=====

please consider the following code (I’m trying to draw a timeline)

1 from matplotlib import pyplot, patches

2 fig = pyplot.figure()

3 ax = fig.add_subplot(‘111’)

4 ax.add_patch(patches.Rectangle((1933,0.25), 73, 0.5))

5 pyplot.show()

that gives me a plot with the x axis that goes from 0.0 to 1.0,

now consider

…

5 ax.set_xlim((1933,1933+73))

6 pyplot.show()

this gives me an x axis that goes exactly from 1933 to 2006,

eventually drawing a line superposed to the lower spine

…

5 ax.plot((1933,1933+73),(0,0))

6 pyplot.show()

gives me what I really want, that is an x axis running from 1930 to

2010, with the limits automatically rounded by matplotlib…

(I noted that the extra line forces a rounding also for the y axis

limits, but that’s not a problem…)

QUESTION

========

I want matplotlib to round the limits of the x axis automatically,

when given explicitly the lower and upper limits of the data, how to?

Thank you in advance

–

“We have met the enemy and he is us.”

                                                    --- Pogo.

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3

INTRO

please consider the following code (I'm trying to draw a timeline)

1 from matplotlib import pyplot, patches
2 fig = pyplot.figure()
3 ax = fig.add_subplot('111')
4 ax.add_patch(patches.Rectangle((1933,0.25), 73, 0.5))
5 pyplot.show()

that gives me a plot with the x axis that goes from 0.0 to 1.0,
now consider

   ...
5 ax.set_xlim((1933,1933+73))
6 pyplot.show()

this gives me an x axis that goes _exactly_ from 1933 to 2006,
eventually drawing a line superposed to the lower spine

   ...
5 ax.plot((1933,1933+73),(0,0))
6 pyplot.show()

gives me what I really want, that is an x axis running from 1930 to
2010, with the limits automatically rounded by matplotlib...

(I noted that the extra line forces a rounding also for the y axis
limits, but that's not a problem...)

QUESTION

I want matplotlib to round the limits of the x axis automatically,
when given explicitly the lower and upper limits of the data, how to?

I think the initial problem is that ax.add_patch() is not triggering the autoscaling that you are looking for; the higher-level plot() function does so. After your call to ax.add_patch(), try adding ax.autoscale_view().

Eric

···

On 2015/04/05 11:19 PM, giacomo boffi wrote:

Thank you in advance