R help - Mar 2012 - Spacing of text does not match spacing of bars in barplot

I have a very standard barplot. My labels are too long to be printed
horizontally under each bar, so I am using text to put the labels on a 45
degree slant. 

However, the labels are spaced more narrowly than the bars, so on an 8
vertical bar plot, the end of the eighth label is lined up with the seventh
bar.

Preferably I don't want to do every text label separately (I'm having
this
problem on all the graphs where I'm using text()

Using Windows and version 2.14.1

X2sum <- c(42.6,  3.6,  1.8,  3.9, 12.1, 14.3, 14.6 ,28.4)
X2.labels <- c("No earnings", "Less than $5000/year",
"$5K to $10K" , "$10K
to $15K"  , "$ 15K to $20K" ,       "$20K to $25K"  ,  
"$25K to $30K"
,      "Over $30K"   )      

barplot(X2sum)
text(1:8, par("usr")[3] - 0.5, srt = 45, adj = 1, labels =X2.labels,
xpd TRUE)

Thanks,

Jon


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The return value of barplot contains the locations
of the bars that it just drew.  Use that instead of
1:8 when you draw the text:

 > barCenters <- barplot(X2sum)
 > text(barCenters, par("usr")[3] - 0.5, srt = 45, adj = 1, labels
=X2.labels, xpd = TRUE)

Look at help(barplot) for details.

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com 
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at
r-project.org] On Behalf Of jon waterhouse
> Sent: Friday, March 02, 2012 11:52 AM
> To: r-help at r-project.org
> Subject: [R] Spacing of text does not match spacing of bars in barplot
> 
> I have a very standard barplot. My labels are too long to be printed
> horizontally under each bar, so I am using text to put the labels on a 45
> degree slant.
> 
> However, the labels are spaced more narrowly than the bars, so on an 8
> vertical bar plot, the end of the eighth label is lined up with the seventh
> bar.
> 
> Preferably I don't want to do every text label separately (I'm
having this
> problem on all the graphs where I'm using text()
> 
> Using Windows and version 2.14.1
> 
> X2sum <- c(42.6,  3.6,  1.8,  3.9, 12.1, 14.3, 14.6 ,28.4)
> X2.labels <- c("No earnings", "Less than
$5000/year", "$5K to $10K" , "$10K
> to $15K"  , "$ 15K to $20K" ,       "$20K to $25K"
,       "$25K to $30K"
> ,      "Over $30K"   )
> 
> barplot(X2sum)
> text(1:8, par("usr")[3] - 0.5, srt = 45, adj = 1, labels
=X2.labels, xpd > TRUE)
> 
> Thanks,
> 
> Jon
> 
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/Spacing-of-text-does-not-match-spacing-of-
> bars-in-barplot-tp4439635p4439635.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> 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.

On Mar 2, 2012, at 1:52 PM, jon waterhouse wrote:
> I have a very standard barplot. My labels are too long to be printed
> horizontally under each bar, so I am using text to put the labels on a 45
> degree slant. 
> 
> However, the labels are spaced more narrowly than the bars, so on an 8
> vertical bar plot, the end of the eighth label is lined up with the seventh
> bar.
> 
> Preferably I don't want to do every text label separately (I'm
having this
> problem on all the graphs where I'm using text()
> 
> Using Windows and version 2.14.1
> 
> X2sum <- c(42.6,  3.6,  1.8,  3.9, 12.1, 14.3, 14.6 ,28.4)
> X2.labels <- c("No earnings", "Less than
$5000/year", "$5K to $10K" , "$10K
> to $15K"  , "$ 15K to $20K" ,       "$20K to $25K"
,       "$25K to $30K"
> ,      "Over $30K"   )      
> 
> barplot(X2sum)
> text(1:8, par("usr")[3] - 0.5, srt = 45, adj = 1, labels
=X2.labels, xpd > TRUE)
> 
> Thanks,
> 
> Jon

Read ?barplot and take note of the Value section:

A numeric vector (or matrix, when beside = TRUE), say mp, giving the coordinates
of all the bar midpoints drawn, useful for adding to the graph.

If beside is true, use colMeans(mp) for the midpoints of each group of bars, see
example.


Thus:

  mp <- barplot(X2sum)

  text(mp, ...)

You correctly read the R FAQ on the matter, but that example uses plot() rather
than barplot(). The midpoints of the bars are not at integer values.

HTH,

Marc Schwartz