Hi Marshall, It sounds like an interesting idea. I would approach it in a slightly different way. I'd recommending writing a function that returns a geom_bar object - that way you can easily add it on to any existing plot, specifying the appropriate parameters.
If you just wanted to plot that layer, you could do ggplot() + my_bar_function(). Hadley PS. Sorry for the delay in responding! On Fri, Apr 9, 2010 at 9:21 AM, Marshall Feldman <ma...@uri.edu> wrote: > Hi Hadley, > > Thanks for the terrific package! > > If you'd like I could give you my code, but conceptually what I'm trying to > do is pretty simple. > > The chart on this page > (http://www.businessinsider.com/20-reasons-why-the-us-economy-is-dying-and-is-simply-not-going-to-recover-2010-2#hard-to-find-jobs-3) > is pretty typical. It shows a line chart of time series data against a > backdrop of shaded bars that indicate periods of recession. This is what I'm > doing. > > The tis package can do this and has a function that works with ggplot2. > However, I see three problems with the approach in tis. (1) It only adds the > bars to an existing plot being displayed. I would like to have it as a > separate object that can be constructed once and added to any number of > plots whether they are displayed or not. (2) I'd like to see the bars by > themselves on a plot. For consistency's sake, once I do this and am > satisfied with the display, I don't want to have to and do a separate > reconstruction. Instead, I want to take the bars from the satisfactory > display. This way there's less room for accidentally breaking the > consistency of the plots. (3) The tis plots are fixed in their format. They > span the y dimension and have widths equal to the durations of the > recessions. There are instances when one might like something different, > such as stacked bars or multiple bars of varying heights (patterns, etc.) > side-by-side that together have a width equal to the recession's duration. > > Obviously what I'm trying to do can be done with more work, but I'm trying > to minimize unnecessary repetitions. I already coded a function that draws > not only the recession bars but also that can draw bars whose height > represents the value of some variable but with widths equal to the durations > of the recessions. Once I create a free-standing plot, I'd like to be able > to use it in various other contexts, including adding it to other existing > plots. The alternative is to reconstruct the plot as a layer and add it to > the other plots, but this is time-consuming and introduces more room for > programming error. > > Thanks for your help. > > Marsh > > On 4/9/2010 8:48 AM, hadley wickham wrote: > > Other then rebuilding the plots, is there any way either (1) to combine > existing ggplot2 plots or (2) to extract a layer from an existing plot > so that it can be added to another? > > > Not really, although you can always pull apart the plot components. > Can you give an example of what you are trying to achieve? > > Hadley > > > > -- Assistant Professor / Dobelman Family Junior Chair Department of Statistics / Rice University http://had.co.nz/ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
