[R] stacked area chart

[Dimitri Liakhovitski]

Thanks a lot, Ista!

On Tue, Sep 28, 2010 at 10:00 AM, Ista Zahn <izahn at psych.rochester.edu> wrote:
> Hi Dimitri,
> I'm not proficient with base graphics, but here is a ggplot solution:
>
> my.data.m <- melt(my.data, id="date")
> my.data.m$pn <- "+"
> my.data.m[my.data.m$variable %in% c("y", "z"), "pn"] <- "-"
> my.data.m$variable <- factor(my.data.m$variable, levels=c("a", "x", "y", "z"))
> my.data.m$Date <- as.numeric(my.data.m$date)
>
> ggplot(my.data.m, aes(x=Date, y=value, fill=variable)) +
>  geom_area(data=subset(my.data.m, pn=="+")) +
>  geom_area(data=subset(my.data.m, pn=="-")) +
>  scale_x_continuous(breaks=unique(my.data.m$Date),
> labels=unique(my.data.m$date)) +
>  scale_fill_manual(values=c("yellow", "blue", "green", "orange")) +
>  theme_bw() +
>  ylab("Title of Y") +
>  opts(title="Chart title", axis.text.x=theme_text(angle=70, vjust=1, hjust=1))
>
>
> HTH,
> Ista
>
> On Mon, Sep 27, 2010 at 6:05 PM, Dimitri Liakhovitski
> <dimitri.liakhovitski at gmail.com> wrote:
>> I found a solution to my original question (see code below).
>> But I have a question about cosmetics, which I always find very challenging.
>> 1. How can I make all dates appear on the X axis (rotated at 90
>> degrees vs. horizontal)?
>> 2. How can I create vertical grid lines so that at each date there is
>> a gridline?
>> 3. How can I create a legend for colors, but not on top of the graph
>> but on the right side, outside of the graph (because in my real data
>> set I have a lot of variables - so that there'll never be enough space
>> for the legend in the graph itself)
>>
>> Thanks a lot!
>> Dimitri
>>
>>
>> ### Creating a data set with both positives and negatives
>> my.data<-data.frame(date=c(20080301,20080402,20080503,20090301,20090402,20090503,20100301,20100402,20100503),
>> x=c(1.1,1.0,1.6,1,2,1.5,2.1,1.3,1.9),y=c(-4,-3,-6,-5,-7,-5.2,-6,-4,-4.9),
>> z=c(-0.2,-0.3,-0.4,-0.1,-0.2,-0.05,-0.2,-0.15,-0.06),a=c(10,13,15,15,16,17,15,16,14))
>> my.data$date<-as.character(my.data$date)
>> my.data$date<-as.Date(my.data$date,"%Y%m%d")
>> (my.data)
>>
>> positives<-which(colSums(my.data[2:ncol(my.data)])>0) # which vars
>> have positive column sums?
>> negatives<-which(colSums(my.data[2:ncol(my.data)])<0) # which vars
>> have negative column sums?
>>
>> y.max<-1.1*max(rowSums(my.data[names(positives)])) # the max on the y
>> axis of the chart
>> y.min<-1.1*min(rowSums(my.data[names(negatives)])) # the min on the y
>> axis of the chart
>> ylim <- c(y.min, y.max)
>> order.positives<-rev(rank(positives))
>> order.of.pos.vars<-names(order.positives)
>> order.negatives<-rev(rank(negatives))
>> order.of.neg.vars<-names(order.negatives)
>> order<-c(order.negatives,order.positives)
>> order.of.vars<-names(order)   # the order of variables on the chart -
>> from the bottom up
>> ### so, the bottom-most area should be for z, the second from the
>> bottom area- for y (above z)
>>
>> all.colors<-c('red','blue','green','orange','yellow','purple')
>> xx <- c(my.data$date, rev(my.data$date))
>> bottom.y.coordinates<-rowSums(my.data[names(negatives)])
>>
>> plot(x=my.data$date, y=bottom.y.coordinates, ylim=ylim, col='white',
>> type='l', xaxt='n',
>>    ylab='Title for Y', xlab='Date', main='Chart Title')
>>
>> for(var in order.of.neg.vars){
>>        top.line.coords<-bottom.y.coordinates-my.data[[var]]
>>        bottom.coords<-c(bottom.y.coordinates,rev(top.line.coords))
>>        polygon(xx,bottom.coords,col=all.colors[which(names(my.data) %in% var)])
>>        bottom.y.coordinates<-top.line.coords
>> }
>>
>> for(var in order.of.pos.vars){
>>        top.line.coords<-bottom.y.coordinates+my.data[[var]]
>>        bottom.coords<-c(bottom.y.coordinates,rev(top.line.coords))
>>        polygon(xx,bottom.coords,col=all.colors[which(names(my.data) %in% var)])
>>        bottom.y.coordinates<-top.line.coords
>> }
>>
>>
>>
>> On Mon, Sep 27, 2010 at 11:47 AM, Dimitri Liakhovitski
>> <dimitri.liakhovitski at gmail.com> wrote:
>>> Dear R-ers!
>>>
>>> Asking for your help with building the stacked area chart for the
>>> following simple data (several variables - with date on the X axis):
>>>
>>> ### Creating a data set
>>> my.data<-data.frame(date=c(20080301,20080402,20080503,20090301,20090402,20090503,20100301,20100402,20100503),
>>> x=c(1.1,1.0,1.6,1,2,1.5,2.1,1.3,1.9),y=c(-4,-3,-6,-5,-7,-5.2,-6,-4,-4.9),
>>> z=c(-0.2,-0.3,-0.4,-0.1,-0.2,-0.05,-0.2,-0.15,-0.06),a=c(4,3,5,5,6,7,5,6,4))
>>> my.data$date<-as.character(my.data$date)
>>> my.data$date<-as.Date(my.data$date,"%Y%m%d")
>>> (my.data)
>>>
>>> I'd like the variables whose column values sum up to a negative number
>>> to be below zero on that chart and those that add up to a positive
>>> number to be above zero in the chart. I am calculating values for ylim
>>> and for the order of the variable entry (bottom up) like this:
>>>
>>> positives<-which(colSums(my.data[2:ncol(my.data)])>0) # which vars
>>> have positive column sums?
>>> negatives<-which(colSums(my.data[2:ncol(my.data)])<0) # which vars
>>> have negative column sums?
>>>
>>> y.max<-1.1*max(rowSums(my.data[names(positives)])) # the max on the y
>>> axis of the chart
>>> y.min<-1.1*min(rowSums(my.data[names(negatives)])) # the min on the y
>>> axis of the chart
>>> ylim <- c(y.min, y.max)  # ylim for the stacked area chart
>>>
>>> order.positives<-rev(rank(positives))
>>> order.negatives<-rev(rank(negatives))
>>> order<-c(order.negatives,order.positives)
>>> order.of.vars<-names(order)   # the order of variables on the chart - bottom up
>>> ### so, the bottom-most area should be for z, and the second from the
>>> bottom area- for y (above z) - they'll be below zero
>>> ### and above zero we'll have a first and x second (on top of a).
>>>
>>> Thanks a lot for your advice!
>>>
>>> --
>>> Dimitri Liakhovitski
>>> Ninah Consulting
>>> www.ninah.com
>>>
>>
>>
>>
>> --
>> Dimitri Liakhovitski
>> Ninah Consulting
>> www.ninah.com
>>
>> ______________________________________________
>> R-help at 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.
>>
>
>
>
> --
> Ista Zahn
> Graduate student
> University of Rochester
> Department of Clinical and Social Psychology
> http://yourpsyche.org
>



-- 
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com