Stacked Area Histogram in R
I ran a Pig job on a Hadoop cluster that crunched a bunch of data down into something R can handle to do a cohort analysis. I have the following script, and as of the second to last line I have the data in the format:
> names(data)
[1] "VisitWeek" "ThingAge" "MyMetric"
VisitWeek is a Date. ThingAge and MyMetric are integers.
The data looks like:
2010-02-07 49 12345
The script I have so far is:
# Load ggplot2 for开发者_如何学编程 charting
library(ggplot2);
# Our file has headers - column names
data = read.table('weekly_cohorts.tsv',header=TRUE,sep="\t");
# Print the names
names(data)
# Convert to dates
data$VisitWeek = as.Date(data$VisitWeek)
data$ThingCreation = as.Date(data$ThingCreation)
# Fill in the age column
data$ThingAge = as.integer(data$VisitWeek - data$ThingCreation)
# Filter data to thing ages lt 10 weeks (70 days) + a sanity check for gt 0, and drop the creation week column
data = subset(data, data$ThingAge <= 70, c("VisitWeek","ThingAge","MyMetric"))
data = subset(data, data$ThingAge >= 0)
print(ggplot(data, aes(x=VisitWeek, y=MyMetric, fill=ThingAge)) + geom_area())
This last line does not work. I've tried lots of variations, bars, histograms, but as usual R docs defeat me.
I want it to show a standard Excel style stacked area chart - one time series for each ThingAge stacked across the weeks in the x axis, with the date on the y axis. An example of this kind of chart is here: http://upload.wikimedia.org/wikipedia/commons/a/a1/Mk_Zuwanderer.png
I've read the docs here: http://had.co.nz/ggplot2/geom_area.html and http://had.co.nz/ggplot2/geom_histogram.html and this blog http://chartsgraphs.wordpress.com/2008/10/05/r-lattice-plot-beats-excel-stacked-area-trend-chart/ but I can't quite make it work for me.
How can I achieve this?
library(ggplot2)
set.seed(134)
df <- data.frame(
VisitWeek = rep(as.Date(seq(Sys.time(),length.out=5, by="1 day")),3),
ThingAge = rep(1:3, each=5),
MyMetric = sample(100, 15))
ggplot(df, aes(x=VisitWeek, y=MyMetric)) +
geom_area(aes(fill=factor(ThingAge)))
gives me the image below. I suspect your problem lies in correctly specifying the fill mapping for the area plot: fill=factor(ThingAge)
ggplot(data.set, aes(x = Time, y = Value, colour = Type)) + geom_area(aes(fill = Type), position = 'stack')
you need to give the geom_area a fill element and also stack it (though that might be a default)
found here http://www.mail-archive.com/r-help@r-project.org/msg84857.html
I was able to get my result with this:
I loaded the stackedPlot() function from https://stat.ethz.ch/pipermail/r-help/2005-August/077475.html
The function (not mine, see link) was:
stackedPlot = function(data, time=NULL, col=1:length(data), ...) {
if (is.null(time))
time = 1:length(data[[1]]);
plot(0,0
, xlim = range(time)
, ylim = c(0,max(rowSums(data)))
, t="n"
, ...
);
for (i in length(data):1) {
# Die Summe bis zu aktuellen Spalte
prep.data = rowSums(data[1:i]);
# Das Polygon muss seinen ersten und letzten Punkt auf der Nulllinie haben
prep.y = c(0
, prep.data
, 0
)
prep.x = c(time[1]
, time
, time[length(time)]
)
polygon(prep.x, prep.y
, col=col[i]
, border = NA
);
}
}
Then I reshaped my data to wide format. Then it worked!
wide = reshape(data, idvar="ThingAge", timevar="VisitWeek", direction="wide");
stackedPlot(wide);
Turning integers into factors and using geom_bar rather than geom_area worked for me:
df<-expand.grid(x=1:10,y=1:6)
df<-cbind(df,val=runif(60))
df$fx<-factor(df$x)
df$fy<-factor(df$y)
qplot(fy,val,fill=fx,data=df,geom='bar')
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