I'm a ggplot2 newbie and have a rather simple question regarding time-series plots.
I have a data set in which the data is structured as follo开发者_JS百科ws.
Area 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
MIDWEST 10 6 13 14 12 8 10 10 6 9
How do I generate a time series when the data is structured in this format.
With the reshape
package, I could just alter the data to look like:
totmidc <- melt(totmidb, id="Area")
totmidc
Area variable value
1 MIDWEST 1998 10
2 MIDWEST 1999 6
3 MIDWEST 2000 13
4 MIDWEST 2001 14
5 MIDWEST 2002 12
6 MIDWEST 2003 8
7 MIDWEST 2004 10
8 MIDWEST 2005 10
9 MIDWEST 2006 6
10 MIDWEST 2007 9
Then run the following code to get the desired plot.
ggplot(totmidc, aes(Variable, Value)) + geom_line() + xlab("") + ylab("")
However, is it possible to generate a time series plot from the first object in which the columns represent the years.
What is the error that ggplot2 gives you? The following seems to work on my machine:
Area <- as.numeric(unlist(strsplit("1998 1999 2000 2001 2002 2003 2004 2005 2006 2007", "\\s+")))
MIDWEST <-as.numeric(unlist(strsplit("10 6 13 14 12 8 10 10 6 9", "\\s+")))
qplot(Area, MIDWEST, geom = "line") + xlab("") + ylab("")
#Or in a dataframe
df <- data.frame(Area, MIDWEST)
qplot(Area, MIDWEST, data = df, geom = "line") + xlab("") + ylab("")
You may also want to check out the ggplot2 website for details on scale_date
et al.
I am guessing that with "time series plot" you mean you want to get a bar chart instead of a line chart?
In that case, you have to modify your code only slightly to pass the correct parameters to geom_bar(). The geom_bar default stat is stat_bin, which will calculate a frequency count of your categories on the x-scale. With your data you want to override this behaviour and use stat_identity.
library(ggplot2)
# Recreate data
totmidc <- data.frame(
Area = rep("MIDWEST", 10),
variable = 1998:2007,
value = round(runif(10)*10+1)
)
# Line plot
ggplot(totmidc, aes(variable, value)) + geom_line() + xlab("") + ylab("")
# Bar plot
# Note that the parameter stat="identity" passed to geom_bar()
ggplot(totmidc, aes(x=variable, y=value)) + geom_bar(stat="identity") + xlab("") + ylab("")
This produces the following bar plot:
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