# RFC: log='z' for image, contour, persp?

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## RFC: log='z' for image, contour, persp?

 I've been thinking of adding the possibility of including "z" among the axes to be logged in image, contour, and persp.  In the first two, it would only affect where the breaks were set if they are calculated automatically; it would have a bigger effect in persp. For example, image(x, y, z, log="z") would set 12 colours evenly spaced on a log scale of the z values.  (12 because that's the default). We already support image(x, y, z, log="x") to scale the x axis (though there's a spurious warning; I'll fix that). image(z, log="x") fails because it tries to take a log of zero. Does it seem like a good idea for these 3D functions to support log="z" the way 2D functions do? Duncan Murdoch ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
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## Re: RFC: log='z' for image, contour, persp?

 >>>>> "Duncan" == Duncan Murdoch <[hidden email]> >>>>>     on Tue, 09 May 2006 18:41:09 -0400 writes:     Duncan> I've been thinking of adding the possibility of     Duncan> including "z" among the axes to be logged in image,     Duncan> contour, and persp.  In the first two, it would only     Duncan> affect where the breaks were set if they are     Duncan> calculated automatically; it would have a bigger     Duncan> effect in persp.     Duncan> For example,     Duncan> image(x, y, z, log="z")     Duncan> would set 12 colours evenly spaced on a log scale of     Duncan> the z values.  (12 because that's the default).     Duncan> We already support     Duncan> image(x, y, z, log="x")     Duncan> to scale the x axis (though there's a spurious     Duncan> warning; I'll fix that).     Duncan> image(z, log="x")     Duncan> fails because it tries to take a log of zero.     Duncan> Does it seem like a good idea for these 3D functions     Duncan> to support log="z" the way 2D functions do? Yes, I think it's a good idea. You forgot to mention   filled.contour() which is  image() + "color - legend" For that one, it would be particularly useful to automatically get a "evenly space in log-scale" one.     Duncan> Duncan Murdoch Note that for things like the above, I have added a simple function lseq() in package 'sfsmisc' -- which I have contemplated moving to R.  Maybe this could happen at the same time and you could make use of it for the above. Martin ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel