[R] Barchart bar lengths not proportionate

[S Ellison]

I think you should rather look at the origin= parameter in barchart. See

?panel.barchart for a discussion of this exact problem:
"  origin: the origin for the bars.  For grouped displays with 'stack
=
          TRUE', this argument is ignored and the origin set to 0. 
          Otherwise, defaults to 'NULL', in which case bars start at
          the left (or bottom) end of a panel.  This choice is
somewhat
          unfortuntate, as it can be misleading, but is the default
for
          historical reasons.  For tabular (or similar) data, 'origin
=
          0' is usually more appropriate; if not, one should
reconsider
          the use of a bar chart in the first place (dot plots are
          often a good alternative). "

The result of setting origin is more sensible:
require(lattice)
da <- expand.grid(A=c("a","b"), x=1:4)
da$y <- c(1,5,6,3,2,0,6,0)

barchart(y~x|A, data=da, horizontal=FALSE)

barchart(y~x|A, data=da, horizontal=FALSE, origin=0)

>>> Walmes Zeviani <walmeszeviani at hotmail.com> 14/01/2010 14:49:01 >>>

Rex,

I think this problem can be solved using xlim()/ylim() argument. Look
at the
follwing code:

require(lattice)
da <- expand.grid(A=c("a","b"), x=1:4)
da$y <- c(1,5,6,3,2,0,6,0)

barchart(y~x|A, data=da, horizontal=FALSE)

barchart(y~x|A, data=da, horizontal=FALSE,
         ylim=c(0, 1.05*max(da$y)))

At your disposal.
Walmes.



Rex C. Eastbourne wrote:
> 
> When I use barchart (with default formatting options), I get bars
whose
> lengths/heights are not proportional to their value. For example:
> 
> http://drop.io/wbagm6s/asset/capture-png 
> 
> Many of the values in this chart are 1; however, because the blue
bars
> extend to the left of the "0" tick mark, those bars appear to
represent
> higher numeric values. Is there a way to make the length of the bar
> proportional to the data value, so that people looking at my chart
are not
> misled?
> 
> Thanks,
> 
> Rex
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.
> 
> 


-----
..oooO
..................................................................................................
..(....)... 0ooo...                              Walmes Zeviani
...\..(.....(.....)...     Master in Statistics and Agricultural
Experimentation
....\_)..... )../....       walmeszeviani at hotmail.com, Lavras - MG,
Brasil
............
(_/............................................................................................
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