[R] Plots from categorial data

[deepayan.sarkar at gmail.com]

On 7/1/07, Jim Lemon <jim at bitwrit.com.au> wrote:
> Christoph Krammer wrote:
> > Hello everybody,
> >
> > Since my first message was caught by the spam filter, I just try to do it
> > again:
> >
> > I want to use R to generate plots from categorial data. The data contains
> > results from OCR scans over images with are preprocessed by different
> image
> > filtering techniques. A small sample data set looks as following:
> >
> >
> >>data <- read.csv("d:/tmp_da/sql_data/filter_d_tool.csv", header=T)
> >>data
> >
> >       ocrtool filter_setting avg.hit.
> > 1  FineReader            2x1    0.383
> > 2  FineReader            2x2    0.488
> > 3  FineReader            3x2    0.268
> > 4  FineReader            3x3    0.198
> > 5  FineReader            4x3    0.081
> > 6  FineReader            4x4    0.056
> > 7        gocr            2x1    0.153
> > 8        gocr            2x2    0.102
> > 9        gocr            3x2    0.047
> > 10       gocr            3x3    0.052
> > 11       gocr            4x3    0.014
> > 12       gocr            4x4    0.002
> > 13      ocrad            2x1    0.085
> > 14      ocrad            2x2    0.094
> > 15      ocrad            3x2    0.045
> > 16      ocrad            3x3    0.050
> > 17      ocrad            4x3    0.025
> > 18      ocrad            4x4    0.009
> >
> >
> > I now want to draw a plot with the categories (filter_setting) as X axis,
> > and the avg_hit as Y axis. There should be lines for each ocrtool.
> >
> > But when I draw a plot, the resulting plot always contains bars, even if I
> > specify type="n".
> >
> >>plot(data$filter_setting, data$avg.hit., type="n")
> >
> >
> > When I only plot the categories, without data, there appear strange grey
> > (but empty) boxes.
> >
> >>plot(data$filter_setting, type="n")
> >
> >
> > Who do I get a clean white box to draw the different lines in?
> >
> Hi Christoph,
>
> How about this?
>
> plot(as.numeric(krammer$filter_setting[1:6]),krammer$avg_hit[1:6],
>   type="b",col=2,ylim=c(0,0.5),main="OCR performance",
>   xlab="Filter setting",ylab="Average hits",axes=FALSE)
> points(as.numeric(krammer$filter_setting[7:12]),krammer$avg_hit[7:12],
>   type="b",col=3)
> points(as.numeric(krammer$filter_setting[13:18]),krammer$avg_hit[13:18],
>   type="b",col=4)
> box()
> axis(1,at=1:6,labels=c("2x1","2x2","3x2","3x3","4x3","4x4"))
> axis(2)

And this is mostly equivalent to

with(krammer, interaction.plot(filter_setting, ocrtool, avg_hit))

or (with the original names)

with(data, interaction.plot(filter_setting, ocrtool, avg.hit.))

-Deepayan