[R] is there a way to avoid "traveling" grid?

Tue Oct 5 17:49:18 CEST 2010

Thierry,
your ggplot solution really looks great and very parsimonious!
May I ask a couple of questions?
1. Is there a way to make the grid appear on top of the colored areas
instead of under them - like I did in the plot solution?
2. In your code line Molten2$variable <- factor(Molten2$variable,
levels = c("z", "y", "x","a")) - how did you chose the order of the
levels? It's important for me to know because I'll have to deal with a
lot of variables and would like to automate this part (you might have
noticed I want the variable with the smallest negatives to be first at
the bottom of the chart and the variable with the smallest positive to
be at the top).
3. In your scale_fill_manual line of code - looks like the order is
manual again. Is there a way to define the colors, so to say
"automatically" - in accordance to the areas of the chart?

Thanks a lot!

On Tue, Oct 5, 2010 at 11:28 AM, ONKELINX, Thierry
<Thierry.ONKELINX at inbo.be> wrote:
> Dear Dimitri,
>
> Ggplot2 solves your problem with the gridlines and requires much less
> code. You only need to reshape your data somewhat.
>
> library(ggplot2)
> #changing the dataset
> my.data2 <- my.data
> my.data2$x <- my.data$x + my.data$a
> my.data2$z <- my.data$y + my.data$z
> Molten2 <- melt(my.data2, id.vars = "date")
> Molten2$variable <- factor(Molten2$variable, levels = c("z", "y", "x",
> "a"))
>
> #basic plot
> ggplot(Molten2, aes(x = date, y = value, fill = variable)) +
>        geom_area(position = "identity")
>
> #changing the lay-out a bit
> ggplot(Molten2, aes(x = date, y = value, fill = variable)) +
>        geom_area(position = "identity") +
>        scale_fill_manual(value = c(z = "orange", y = "green", x =
> "blue", a = "yellow")) +
>        scale_x_date(major = "months", format="%d-%m-%Y") +
>        opts(axis.text.x = theme_text(angle = 90, hjust = 1))
>
> HTH,
>
> Thierry
>
> ------------------------------------------------------------------------
> ----
> ir. Thierry Onkelinx
> Instituut voor natuur- en bosonderzoek
> team Biometrie & Kwaliteitszorg
> Gaverstraat 4
> 9500 Geraardsbergen
> Belgium
>
> Research Institute for Nature and Forest
> team Biometrics & Quality Assurance
> Gaverstraat 4
> 9500 Geraardsbergen
> Belgium
>
> tel. + 32 54/436 185
> Thierry.Onkelinx at inbo.be
> www.inbo.be
>
> To call in the statistician after the experiment is done may be no more
> than asking him to perform a post-mortem examination: he may be able to
> say what the experiment died of.
> ~ Sir Ronald Aylmer Fisher
>
> The plural of anecdote is not data.
> ~ Roger Brinner
>
> The combination of some data and an aching desire for an answer does not
> ensure that a reasonable answer can be extracted from a given body of
> data.
> ~ John Tukey
>
>
>> -----Oorspronkelijk bericht-----
>> Van: r-help-bounces at r-project.org
>> [mailto:r-help-bounces at r-project.org] Namens Dimitri Liakhovitski
>> Verzonden: dinsdag 5 oktober 2010 16:37
>> Aan: r-help at r-project.org
>> Onderwerp: [R] is there a way to avoid "traveling" grid?
>>
>> Hello!
>>
>> If you run the whole code below, it'll produce a stacked diagram. And
>> it looks good - because the tick-marks are aligned with the grid.
>> However, if I stretch the graph window, grid becomes misaligned with
>> the tickmarks. Or, rather, it seems aligned for the first and the last
>> tick mark, but not for tickmarks in between.
>> Can it be addressed?
>> Thank you!
>>
>> Dimitri
>>
>>
>> ### Creating a data set with both positives and negatives
>> my.data<-data.frame(date=c(20080301,20080401,20080501,20080601
> ,20080701,20080801,20080901,20081001,20081101,20081201,20090101,20090201
> ,20090301,20090401,20090501,20090601,20090701,20090801,20090901,20091001
> ,20091101,20091201,> 20100101,20100201,20100301,20100402,20100503),
>> x=c(1.1, 1, 1.6, 1, 2, 1.5, 2.1, 1.3, 1.9, 1.1, 1, 1.6, 1, 2, 1.5,
>> 2.1, 1.3, 1.9, 1.1, 1, 1.6, 1, 2, 1.5, 2.1, 1.3, 1.9),
>> y=c(-4,-3,-6,-5,-7,-5.2,-6,-4,-4.9,-4,-3,-6,-5,-7,-5.2,-6,-4,-
>> 4.9,-4,-3,-6,-5,-7,-5.2,-6,-4,-4.9),
>> z=c(-0.2,-0.3,-0.4,-0.1,-0.2,-0.05,-0.2,-0.15,-0.06,-0.2,-0.3,
>> -0.4,-0.1,-0.2,-0.05,-0.2,-0.15,-0.06,-0.06,-0.2,-0.3,-0.4,-0.
>> 1,-0.2,-0.05,-0.2,-0.15),
>> a=c(10,13,15,15,16,17,15,16,14,10,13,15,15,16,17,15,16,14,10,1
>> 3,15,15,16,17,15,16,14))
>> my.data$date<-as.character(my.data$date)
>> my.data$date<-as.Date(my.data$date,"%Y%m%d")
>> (my.data)
>> str(my.data)
>>
>> positives<-which(colSums(my.data[2:ncol(my.data)])>0) # which vars
>> have positive column sums?
>> negatives<-which(colSums(my.data[2:ncol(my.data)])<0) # which vars
>> have negative column sums?
>>
>> y.max<-1.1*max(rowSums(my.data[names(positives)])) # the max on the y
>> axis of the chart
>> y.min<-1.1*min(rowSums(my.data[names(negatives)])) # the min on the y
>> axis of the chart
>> ylim <- c(y.min, y.max)
>> order.positives<-rev(rank(positives))
>> order.of.pos.vars<-names(order.positives)
>> order.negatives<-rev(rank(negatives))
>> order.of.neg.vars<-names(order.negatives)
>> order<-c(order.negatives,order.positives)
>> order.of.vars<-names(order)   # the order of variables on the chart -
>> from the bottom up
>> ### so, the bottom-most area should be for z, the second from the
>> bottom area- for y (above z)
>>
>> all.colors<-c('red','blue','green','orange','yellow','purple')
>> xx <- c(my.data$date, rev(my.data$date))
>> bottom.y.coordinates<-rowSums(my.data[names(negatives)])
>>
>>
>> par(mar=c(5,4,4,6),xpd=F)
>> plot(x=my.data$date, y=bottom.y.coordinates, ylim=ylim, col='white',
>> type='l', xaxt='n',
>>       ylab='Title for Y', xlab="", main='Chart Title')
>>
>> for(var in order.of.neg.vars){
>>       top.line.coords<-bottom.y.coordinates-my.data[[var]]
>>       bottom.coords<-c(bottom.y.coordinates,rev(top.line.coords))
>>
>> polygon(xx,bottom.coords,col=all.colors[which(names(my.data)
>> %in% var)])
>>       bottom.y.coordinates<-top.line.coords
>> }
>>
>> for(var in order.of.pos.vars){
>>       top.line.coords<-bottom.y.coordinates+my.data[[var]]
>>       bottom.coords<-c(bottom.y.coordinates,rev(top.line.coords))
>>
>> polygon(xx,bottom.coords,col=all.colors[which(names(my.data)
>> %in% var)])
>>       bottom.y.coordinates<-top.line.coords
>> }
>>
>> axis(1, labels =format(as.Date(my.data$date, origin="1970-01-01"),
>> "%Y-%m-%d"), at=my.data$date, las=2,cex.axis=0.7)
>> grid(nx=(length(my.data$date)-1),ny=NULL,col = "lightgray", lty =
>> "dotted",lwd = par("lwd"))
>>
>> legend(par()$usr[2],
>>   mean(par()$usr[3:4]),
>>   c("Blue","Yellow","Green","Orange"),
>>   xpd=T,
>>   bty="n",
>>   pch=12,
>>   col=c("Blue","Yellow","Green","Orange"))
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>>
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-- 
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com