On Thu, 21 May 2009, Prew, Paul wrote:
Hello,
I'm trying to use the vcd package to analyze survey data. Expert judges
ranked possible features for product packaging. Seven features were
listed, and 19 judges split between 2 cities ranked them.
The following code (1) works, but the side-by-side plots for Cities PX,
SF are shrunk too much. Stacking PX on top of SF would make for a
better plot. (I could switch the order of Feature and Rank dimensions,
and go with the default side-by-side, but would prefer not to).
Several comments:
- Adding keep_aspect_ratio = TRUE does probably change what you call
"shrunk too much". By default is aspect ratio is kept fixed for
2-way displays.
- I would switch the splitting order of Feature/Rank because you
probably want the distribution of ranks for a given feature and
not the other way round. In that case, you might find etting
split_vertical = TRUE aesthetically more pleasing. But it's probably
a matter of taste.
- Setting gp = shading_max is not really the best choice: If you would
want a conditional independence test based on the maximum of residuals
you should use panel = cotab_coindep. See the JCGS paper in the
references and the accompanying vignette("residual-shadings", package
= "vcd") for more details. But note that the double maximum test
is not the most powerful test against ordinal alternatives (as one
might expect due to the ordered Rank variable).
hth,
Z
(1)
cotabplot(~ Rank + Feature| Cities, data = Pack.dat, gp = shading_max,
rot_labels = c(90, 0, 0, 0),just_labels = c("left", "left",
"left", "right"),set_varnames = c(Feature = ""))
Reading the vcd help, I got lost trying to understand the
panel-generating parameters I should use. My best guess was below (2),
but gave an error message. Clearly, I don't know what the paneling is
asking for. This is where I would like some advice, if anyone is
familiar with vcd.
(2)
#### Tried to change the layout of trellis plot from horizontal to
vertical
Pack.mos<-mosaic(~Feature + Rank, data = Pack.tab, gp = shading_max,
rot_labels = c(0, 0, 0, 0),just_labels = c("left", "left", "left",
"right"),set_varnames = c(Feature = ""))
## attempt to create an object for panel argument in cotabplot function
pushViewport(viewport(layout = grid.layout(ncol = 1)))
pushViewport(viewport(layout.pos.row = 1))
## tell vcd to change the default layout, and what to put in the top
plot
cotabplot(~ Feature + Rank | Cities, data = Pack.dat, panel = Pack.mos,
Pack.dat[["PX"]], gp = shading_max, rot_labels = c(0, 0, 0, 0))
## create mosaic plot that's conditional on Cities; first plot Cities =
PX
## panel argument is an attempt to modify an example in the vcd help
file
popViewport()
## create the graphic
Error: Cannot pop the top-level viewport (grid and graphics output
mixed?)
# no point in gong on to code the plot for layout.pos.row = 2
str(Pack.tab)
Error in `[.structable`(x, i, args[[2]]) : subscript out of bounds
class(Pack.tab)
[1] "structable" "ftable"
dim(Pack.tab)
[1] 7 2 7
Cities PX SF
Rank Feature
1 Flexible 2 0
Integrate.Probes 1 2
Large/heavy 1 0
Lockout 0 1
Recyclable 3 5
Rigid 0 0
Small/light 2 1
2 Flexible 1 6
Integrate.Probes 2 0
Large/heavy 1 1
Lockout 1 0
Recyclable 2 0
Rigid 1 0
Small/light 2 2
3 Flexible 1 1
Integrate.Probes 3 0
Large/heavy 1 1
Lockout 2 1
Recyclable 1 3
Rigid 0 0
Small/light 0 3
4 Flexible 3 0
Integrate.Probes 0 2
Large/heavy 0 0
Lockout 2 2
Recyclable 0 1
Rigid 1 2
Small/light 3 2
5 Flexible 1 1
Integrate.Probes 1 1
Large/heavy 0 3
Lockout 0 2
Recyclable 2 0
Rigid 3 1
Small/light 2 1
6 Flexible 0 1
Integrate.Probes 1 3
Large/heavy 3 2
Lockout 3 1
Recyclable 0 0
Rigid 2 2
Small/light 0 0
7 Flexible 1 0
Integrate.Probes 1 1
Large/heavy 3 2
Lockout 1 2
Recyclable 1 0
Rigid 2 4
Small/light 0 0
sessionInfo()
R version 2.9.0 RC (2009-04-10 r48318)
i386-pc-mingw32
locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
attached base packages:
[1] grid tcltk stats graphics grDevices utils datasets
[8] methods base
other attached packages:
[1] relimp_1.0-1 vcd_1.2-4 colorspace_1.0-0
MASS_7.2-46
[5] RSiteSearch_0.1-5 brew_1.0-3 lme4_0.999375-30
Matrix_0.999375-26
[9] lattice_0.17-22 Rcmdr_1.4-9 car_1.2-13
loaded via a namespace (and not attached):
[1] tools_2.9.0
If someone can give advice on stacking the two cities' plots, I would be
grateful.
Thanks, Paul
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and provide commented, minimal, self-contained, reproducible code.
