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
>>>>> "Duncan" == Duncan Murdoch <murdoch at stats.uwo.ca> >>>>> 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
Yes, it does. I've needed it more often than not. -Don At 6:41 PM -0400 5/9/06, Duncan Murdoch wrote:>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 > >______________________________________________ >R-devel at r-project.org mailing list >https://stat.ethz.ch/mailman/listinfo/r-devel-- -------------------------------------- Don MacQueen Environmental Protection Department Lawrence Livermore National Laboratory Livermore, CA, USA