Hi:

This is closer, but it is still not what you want; it does, however, show
what
geom_area is doing when it renders the plot, as can be seen by the colors.

data.set <- data.frame(
  Time = c(rep(1, 4),rep(2, 4), rep(3, 4), rep(4, 4)),
  Type = rep(c('a', 'b', 'c', 'd'), 4),
  Value = c(10, 12, 14, 16, 14, 14, 20, 18, 18, 16, 22, 20, 26, 20, 24, 26)
 )
ggplot(data.set, aes(x = Time, y = Value, group = Type)) +
  geom_area(aes(color = Type), fill = 'transparent', position = 'stack')

You can see that a polygon is drawn (and normally filled) for each group,
but the line colors are not what you want and the polygon edges are not
what you want, either. I'd suggest using cumsum() to get cumulative totals
and using geom_line() instead; it would probably be less work...as in:

library(ggplot2)
data2 <- ddply(data.set, .(Time), transform, Csum = cumsum(Value))
ggplot(data2, aes(x = Time, y = Csum, color = Type)) + geom_line()

HTH,
Dennis

On Tue, Feb 9, 2010 at 8:43 PM, Liam Blanckenberg <
liam.blanckenberg@gmail.com> wrote:

> Hi Hadley,
>
> Thank you for taking the time to help me with this - I've constructed
> the following example to illustrate my problem:
>
> require(ggplot2)
>
> data.set <- data.frame(
>  Time = c(rep(1, 4),rep(2, 4), rep(3, 4), rep(4, 4)),
>  Type = rep(c('a', 'b', 'c', 'd'), 4),
>  Value = c(10, 12, 14, 16, 14, 14, 20, 18, 18, 16, 22, 20, 26, 20, 24, 26)
> )
>
> When I use the following code:
>
>   ggplot(data.set, aes(x = Time, y = Value, colour = Type)) +
> geom_area(aes(fill = Type), position = 'stack')
>
> I get a very nice stacked area chart - each layer on the chart
> represents a Type, with the total height of all the layers
> representing the total Value across all Types for a given Time period
> - this is what you would get numerically with the code:
>
>   with(data.set, aggregate(Value, by = list(Time), sum))
>
> I want to achieve exactly the same thing as this, but instead of
> having a coloured area to represent each layer I just want a coloured
> line for each layer. When I use the following code to try and achieve
> this:
>
>   ggplot(data.set, aes(x = Time, y = Value, colour = Type)) +
> geom_line(aes(colour = Type), position = 'stack')
>
> I get a warning/error message: "Missing ymax in position = 'stack'.
> Maybe you want position = 'identity'?". The plot still renders, but
> the lines are not stacked - the plot looks exactly as it would if the
> following code was used instead:
>
>   ggplot(data.set, aes(x = Time, y = Value, colour = Type)) +
> geom_line(aes(colour = Type), position = 'identity')
>
> I suspect that the "position = 'stack'" argument is being ignored and
> 'identity' is being used by default...
>
> Hope this helps,
>
> Liam
>
>
>
>
> On Wed, Feb 10, 2010 at 10:12 AM, hadley wickham <h.wickham@gmail.com>
> wrote:
> > Hi Liam,
> >
> > Yes, that's what that code should do.  Could you please send a small
> > reproducible example?
> >
> > Hadley
> >
> > On Tue, Feb 9, 2010 at 4:21 PM, Liam Blanckenberg
> > <liam.blanckenberg@gmail.com> wrote:
> >> Hadley,
> >>
> >> Thanks for the pointing that error out to me. Unfortunately, revising
> >> my code to:
> >>
> >> p <- ggplot2(~, aes(x = ~, y = ~, colour = Type)) +
> >> geom_line(aes(colour = Type), position = 'stack')
> >>
> >> still does not generate what I'm after. I'm essentially after a line
> >> plot where each 'Type' ('series' in excel lingo) is stacked in an
> >> analogous fashion to a stacked area chart (i.e. geom_area(aes(Fill =
> >> Type), position = 'stack')) - again using lines rather than areas
> >> though.
> >>
> >> This chart should look just like a stacked area chart, however rather
> >> than each 'layer' (representing a given 'Type') being filled with a
> >> colour, each layer should have just a coloured line representing its
> >> values. Summing each line vertically for a given value on the x-axis
> >> across all the layers (i.e. 'Types') should then give the total y
> >> value for that x value (just like vertically summing an area chart).
> >> Really all I'm after is a stacked area chart where the fill for each
> >> 'Type' has been removed, leaving only a line for each (stacked) Type's
> >> value...
> >>
> >> I hope this is somewhat clear!
> >>
> >> Many thanks,
> >>
> >> Liam
> >>
> >>
> >>
> >>
> >>
> >> On Wed, Feb 10, 2010 at 1:53 AM, hadley wickham <h.wickham@gmail.com>
> wrote:
> >>> Hi Liam,
> >>>
> >>> Your syntax is a little off.  You want:
> >>>
> >>> p <- ggplot2(~, aes(x = ~, y = ~, colour = Type)) +
> >>>  geom_area(aes(fill = Type), position = 'stack')
> >>>
> >>> Position isn't an aesthetic.
> >>>
> >>> Hadley
> >>>
> >>> On Sun, Feb 7, 2010 at 10:40 PM, Liam Blanckenberg
> >>> <liam.blanckenberg@gmail.com> wrote:
> >>>> Hi all,
> >>>>
> >>>> I have been hunting around for hours trying to figure out how to
> >>>> generate a stacked line chart using ggplot2. This type of chart can be
> >>>> generated in excel 2007 by selecting: Chart type > Line > Stacked
> >>>> line. I can generate a stacked area chart using the following code:
> >>>>
> >>>>   p <- ggplot2(~, aes(x = ~, y = ~, colour = Type)) +
> >>>> geom_area(aes(position = 'stack', fill = Type))
> >>>>
> >>>> However, when I try and replicate this using the following code for
> geom_line:
> >>>>
> >>>>   p <- ggplot(~, aes(x = ~, y = ~, colour = Type)) +
> >>>> geom_line(aes(position = 'stack'))
> >>>>
> >>>> the resulting plot is not stacked - i.e. each 'Type' is plotted at its
> >>>> actual value rather than cumulatively to form a stacked chart... I
> >>>> have poured through Hadley's ggplot2 book (ggplot2: elegant graphics
> >>>> for data analysis), the R help list and also done general google
> >>>> searching but cannot find a way to generate this type of plot.
> >>>>
> >>>> R version: 2.9.2
> >>>> ggplot2 version: 0.8.5
> >>>> OS: windows 7 (64-bit).
> >>>>
> >>>> Any suggestions or assistance would be greatly appreciated.
> >>>>
> >>>> Regards,
> >>>>
> >>>> Liam
> >>>>
> >>>> ______________________________________________
> >>>> 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.
> >>>>
> >>>
> >>>
> >>>
> >>> --
> >>> http://had.co.nz/
> >>>
> >>
> >
> >
> >
> > --
> > 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.
>

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