On Wed, Jul 7, 2010 at 1:54 AM, Matthias Michler <matthiasmich...@gmx.net> wrote: > On Wednesday July 7 2010 05:53:59 jezhill wrote: >> Hi all, >> >> I've been experimenting with the NonUniformImage class. (Actually I want >> *uniform* pixel spacing, but I want the image x and y coordinates to have >> the correct *scaling* in the style of Matlab's image(x,y,C). The >> AxesImage class, created via pylab.imshow, didn't seem to offer that, so I >> landed on NonUniformImage, but if there's a better solution I'd be >> grateful for tips...) >> >> >> And here's the problem (or bug?): with my Python 2.5.4 and my matplotlib >> 1.0, I go and run the >> http://matplotlib.sourceforge.net/examples/pylab_examples/image_nonuniform. >> html gallery demo but I decide that I want the y axis reversed (as is >> common in image visualization). So I either call >> pylab.gca().invert_yaxis() at the end, or I change one of the lines that >> says >> >> ax.set_ylim(-4,4) >> >> to read >> >> ax.set_ylim(4,-4) >> >> which I believe is the approved method. However the result I get is >> non-sensical: no more image variation in the vertical direction. Can >> anyone tell me what, if anything, I'm doing wrong? > > Hi jez, > > I attached a slightly modified version of the image_nonuniform.py. I > additionally inverted the y-limits in the extent-kwarg and in the set_data of > the last example. I'm not sure why this is needed and if there is a better > solution to it, but at least for me it works. > Does anybody know why we have to invert all data concerning y-axis?
We have to invert because the image data is assumed to be starting in the upper left. You can change this assumption by passing: orgin='lower' All of these options are supported by imshow(), so if one has uniform data and just needs proper data scaling, imshow() will be sufficient. Ryan -- Ryan May Graduate Research Assistant School of Meteorology University of Oklahoma ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
