Re: [Matplotlib-users] set axis square?

[John H. <jdh...@ac...>]

>>>>> "Dominique" == Dominique Orban <Dom...@po...> writes:

    Dominique> Sorry if this is a silly question; i couldn't find the
    Dominique> answer in the source files or the mailing list archive.

    Dominique> I am using matplotlib 0-60.2. Is there an equivalent in
    Dominique> matplotlib to the matlab command 'axis square', to set
    Dominique> the aspect ratio to 1? More generally, can i set the
    Dominique> aspect ratio to any ratio i like? I am interested in
    Dominique> this for plot() and scatter().
There is no axis square at the moment (easy to add though).  But yes,
you can set the axes to any aspect ratio you want.  Rather than
calling 'subplot', call 'axes'.

   # left, bottom, width, height
   axes([0.15, 0.15, 0.7, 0.7])

The numbers are fractions of the figure size.  So left is 0.15*figure
width, bottom is 0.15 * figure height, width is 0.7 * figure width and
height is 0.7 * figure height.  See
http://matplotlib.sourceforge.net/matplotlib.matlab.html#-axes for
more info.

You can control the figure dimensions using the figsize argument (args
in inches, my apologies)

  # figure is 6 inches square
  figure(1, figsize=(6, 6))

See  http://matplotlib.sourceforge.net/matplotlib.matlab.html#-figure.

Here is and example script

    from matplotlib.matlab import *

    side = 7 # side of square in inches
    figure(1, figsize=(side, side))

    # left, bottom, width, height
    axes([0.15, 0.15, 0.7, 0.7])

    N = 500                    # number of scatter points
    scatter(rand(N), rand(N))  # should be square

    savefig('test.ps')
    show()

That said, there is a very important caveat.  This probably won't
appear square on your monitor because the dots per inch on your
monitor likely differ in the horizontal and vertical directions (it
should be square if you save as *.ps and print it on a postscript
printer).  When I implemented freetype fonts for matplotlib, I asked
on this list if anyone was interested in matplotlib supporting dpi in
the x and y direction so that you could actually create figures in
true sizes on the monitor, but there was no interest at the time.  The
freetype lib supports horizontal and vertical dpi, which is why it
came up at the time.

JDH