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## Re: [Matplotlib-users] square plots with linear equal axes -- help

 Re: [Matplotlib-users] square plots with linear equal axes -- help From: kbkb - 2009-07-27 00:43:27 ```Thanks for trying to help Andreas. Those suggestions did not really solve the problem, but I did realize where I was going astray and post that information here to help others. I did see others new to the libraries looking for similar help. First the conceptual misunderstanding: I did not realize the 'figure size', as set by something like plt.gcf().set_size_inches(6,6) includes all area: white plot area, grey surrounding area, labels, etc. Everything inside the window frame. A bad coincidence slowed my realization. I measured the white area inside the axis to be 480x464 pixels, which at 80 dpi worked almost for a 6x6. So, I thought it was close but off just a bit. But, I had set the dpi to 100, and the total frame was exactly 600x600 as it should be. The dimensions of the plot area inside the axes was being set automatically, and just coincidentally worked out to be 480 in one dimension. Solution to get truly square plots of known size with axis scale set: fig = plt.gcf() fig.set_dpi(100) # or whatever you like fig.set_size_inches((6.0,6.0),forward=True) #for example # to control the fraction of the total area set aside for axis tick mark labels, etc. # this is key to keeping the interior plot area square plt.subplots_adjust(left=0.10,bottom=0.10,right=0.95,top=0.95) ## plt.axis('equal') # I had this for a while but do not think it useful plt.gca().grid(True) # to keep the axis scale from being automatically changed as line2d objects are added or removed plt.gca().set_autoscale_on(False) plt.axis([1.0,9.0,1.0,9.0]) # set the axis scale as appropriate plt.show() fig.canvas.draw() Cheers Kersey -- View this message in context: http://www.nabble.com/square-plots-with-linear-equal-axes-----help-tp24638812p24672100.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```

 [Matplotlib-users] square plots with linear equal axes -- help From: kbkb - 2009-07-24 05:25:53 ```Hi This should be so simple, but I have been struggling for a long time trying to create a square plot of exact dimensions (so a series of them can be overlaid later), with x and y axis limits identical and set by me (preferably without the plot limits updating automatically as I add or delete data, but that is a separate issue), while working interactively on a single plot using pyplot in ipython on OS X using the current enthought distribution. with pyplot imported as plt, typical of what I have tried are many variations on plt.plot(*args) with args a list of x,y sets fig = plt.gcf() fig.set_size_inches(6,6,forward='True') to force a redraw ax = plt.gca() ax.grid(True) plt.axis([1.0,10.0,1.0,10.0]) plt.draw() Sometimes the x axis is set correctly, but the y axis is not, and is typically showing more range (approximately 0.8-10.1 for example), possibly because the plot is not square, though it is close, or because the scales are not equal. I have tried adding 'equal' to the plt.axis command, and entering the values as plt.axis(xmin=1.0,xmax=10.0,ymin=1.0,ymax=10.0) and entering just the first three and then plt.axis('equal') and I have tried working with ax.set_aspect('equal') But, I am truly lost as I try to sort out which elements are in control. Any help or leads would be greatly appreciated. Scanning old archives and googling has not yet got me there. kersey -- View this message in context: http://www.nabble.com/square-plots-with-linear-equal-axes-----help-tp24638812p24638812.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```
 Re: [Matplotlib-users] square plots with linear equal axes -- help From: plankton - 2009-07-24 13:13:23 ``` kbkb wrote: > > Hi > This should be so simple, but I have been struggling for a long time > trying to create a square plot of exact dimensions (so a series of them > can be overlaid later), with x and y axis limits identical and set by me > (preferably without the plot limits updating automatically as I add or > delete data, but that is a separate issue), while working interactively on > a single plot using pyplot in ipython on OS X using the current enthought > distribution. > > with pyplot imported as plt, > typical of what I have tried are many variations on > > plt.plot(*args) with args a list of > x,y sets > fig = plt.gcf() > fig.set_size_inches(6,6,forward='True') to force a redraw > ax = plt.gca() > ax.grid(True) > plt.axis([1.0,10.0,1.0,10.0]) > plt.draw() > > Sometimes the x axis is set correctly, but the y axis is not, and is > typically showing more range (approximately 0.8-10.1 for example), > possibly because the plot is not square, though it is close, or because > the scales are not equal. > > I have tried adding 'equal' to the plt.axis command, > and entering the values as > plt.axis(xmin=1.0,xmax=10.0,ymin=1.0,ymax=10.0) > and entering just the first three and then > plt.axis('equal') > and I have tried working with > ax.set_aspect('equal') > > But, I am truly lost as I try to sort out which elements are in control. > Any help or leads would be greatly appreciated. > Scanning old archives and googling has not yet got me there. > > kersey > Hi kersey, maybe it helps if you set the figure size already while you inilialise it. I use e.g. --CODE-- fig = figure(1, figsize=(20,7), dpi = 80) --CODE-- to generate non squared plots. To make a square plot figsize have to be e.g figsize=(10,10). But I do not know if this really works, maybe only the figure has an equal aspect ratio and the real plot not. Otherwise you can set the plot aspect ratio = equal with matplotlib.axes.Axes.set_aspect Details can be found here: http://matplotlib.sourceforge.net/api/axes_api.html#matplotlib.axes.Axes.set_aspect Andreas -- View this message in context: http://www.nabble.com/square-plots-with-linear-equal-axes-----help-tp24638812p24644304.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```
 Re: [Matplotlib-users] square plots with linear equal axes -- help From: kbkb - 2009-07-27 00:43:27 ```Thanks for trying to help Andreas. Those suggestions did not really solve the problem, but I did realize where I was going astray and post that information here to help others. I did see others new to the libraries looking for similar help. First the conceptual misunderstanding: I did not realize the 'figure size', as set by something like plt.gcf().set_size_inches(6,6) includes all area: white plot area, grey surrounding area, labels, etc. Everything inside the window frame. A bad coincidence slowed my realization. I measured the white area inside the axis to be 480x464 pixels, which at 80 dpi worked almost for a 6x6. So, I thought it was close but off just a bit. But, I had set the dpi to 100, and the total frame was exactly 600x600 as it should be. The dimensions of the plot area inside the axes was being set automatically, and just coincidentally worked out to be 480 in one dimension. Solution to get truly square plots of known size with axis scale set: fig = plt.gcf() fig.set_dpi(100) # or whatever you like fig.set_size_inches((6.0,6.0),forward=True) #for example # to control the fraction of the total area set aside for axis tick mark labels, etc. # this is key to keeping the interior plot area square plt.subplots_adjust(left=0.10,bottom=0.10,right=0.95,top=0.95) ## plt.axis('equal') # I had this for a while but do not think it useful plt.gca().grid(True) # to keep the axis scale from being automatically changed as line2d objects are added or removed plt.gca().set_autoscale_on(False) plt.axis([1.0,9.0,1.0,9.0]) # set the axis scale as appropriate plt.show() fig.canvas.draw() Cheers Kersey -- View this message in context: http://www.nabble.com/square-plots-with-linear-equal-axes-----help-tp24638812p24672100.html Sent from the matplotlib - users mailing list archive at Nabble.com. ```
 Re: [Matplotlib-users] square plots with linear equal axes -- help From: Jae-Joon Lee - 2009-07-27 16:42:34 ```Well, I think the meaning of the axis("equal") is a bit misleading (at least to me), but if you look at the documentation, it says that it changes the xlimit and ylimit (limits in data coordinate), so this is NOT what you want. What you need is axis("scaled") or axis("image"). http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.axis With this, you will have square axes regardless of the figure size or subplot params (assuming that the x- and y- data limits are same). Regards, -JJ On Sun, Jul 26, 2009 at 8:43 PM, kbkb wrote: > > Thanks for trying to help Andreas. > > Those suggestions did not really solve the problem, but I did realize where > I was going astray and post that information here to help others.  I did see > others new to the libraries looking for similar help. > > First the conceptual misunderstanding:  I did not realize the 'figure size', > as set by something like > plt.gcf().set_size_inches(6,6) includes all area: white plot area, grey > surrounding area, labels, etc.  Everything inside the window frame.  A bad > coincidence slowed my realization.  I measured the white area inside the > axis to be 480x464 pixels, which  at 80 dpi worked almost for a 6x6.  So, I > thought it was close but off just a bit.  But, I had set the dpi to 100, and > the total frame was exactly 600x600 as it should be.  The dimensions of the > plot area inside the axes was being set automatically, and just > coincidentally worked out to be 480 in one dimension. > > Solution to get truly square plots of known size with axis scale set: >    fig = plt.gcf() >    fig.set_dpi(100)  # or whatever you like >    fig.set_size_inches((6.0,6.0),forward=True) #for example >    # to control the fraction of the total area set aside for axis tick mark > labels, etc. >    # this is key to keeping the interior plot area square >    plt.subplots_adjust(left=0.10,bottom=0.10,right=0.95,top=0.95) >    ## plt.axis('equal')  # I had this for a while but do not think it > useful >    plt.gca().grid(True) >    # to keep the axis scale from being automatically changed as line2d > objects are added or removed >    plt.gca().set_autoscale_on(False) >    plt.axis([1.0,9.0,1.0,9.0])  # set the axis scale as appropriate >    plt.show() >    fig.canvas.draw() > > Cheers > Kersey > > -- > View this message in context: http://www.nabble.com/square-plots-with-linear-equal-axes-----help-tp24638812p24672100.html > Sent from the matplotlib - users mailing list archive at Nabble.com. > > > ------------------------------------------------------------------------------ > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@... > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > ```