Okay I see what's going on now. The output from axis('tight') specifies the limits of the two axes:
> (-0.33718689788053952, > 7.0809248554913298, > -0.34782608695652173, > 7.3043478260869561) As you can see it's actually setting negative minimum limits for both axes, which is why the axes are offset from the (0,0) position. The clue to this behaviour is in the axis function docstring: > axis('auto') or 'normal' (deprecated) restores default behavior; > axis limits are automatically scaled to make the data fit > comfortably within the plot box. and > axis('tight') changes x and y axis limits such that all data is > shown. If all data is already shown, it will move it to the center > of the figure without modifying (xmax-xmin) or (ymax-ymin). Note > this is slightly different than in matlab. Neither of those will necessarily set the xmin and ymin of the axes to 0. It depends on what data you've plotted before calling axis(). I found that if I call axis('tight') before plotting anything (i.e. before calling plot or scatter) then the axes xmin and ymin do get set to 0, but this is because at the time of calling axis('tight') there is no data to show. If you call axis('tight') after plotting data then (contrary to the docstring) it seems to adjust the axes so that all data is shown **and none of it is too close to the axes**, there is some degree of padding, although it is tighter than with axis('auto'). I'm not sure about this 'auto' and 'tight' behaviour. To my eye the corner formed by the x and y axes at the bottom-left signifies (0,0), unless otherwise stated. The padding applied by 'normal' and 'tight' breaks this expectation. In my case, when I don't have any numerical labels on the axes to show that they begin at (-0.34,-0.35), I should probably make sure that they begin at (0,0). You can explicitly set the axes limits with axis(xmin=0,ymin=0). ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users