[R] ggplot2 customizing a plot

[Ista Zahn]

Hi,

On Thu, Feb 21, 2013 at 4:12 AM, Alaios <alaios at yahoo.com> wrote:
> Hello Ista,
> I would like to thank you for your reply!
>
> Your code is indeed an improvement.
>
> This is my code now and there are two things still missing.
>
> DataToPlot<-matrix(data=runif(9),nrow=3,dimnames=list(seq(1,3),seq(4,6)))
> require(reshape)
> require(ggplot2)
> require(raster)
>
>
> cols<-colours()
> cols<-cols[1:(nrow(DataToPlot)*ncol(DataToPlot))]
> tdm<-melt(DataToPlot)
>
> p<- ggplot(tdm, aes(x = Var2, y = Var1, fill = factor(value))) +
> labs(x = "MHz", y = "Threshold", fill = "Duty Cycle") +
> geom_raster(alpha=.5) +
> scale_fill_manual(values=cols,breaks=c("1","0.9","0.8","0.7","0.6","0.5","0.4","0.3","0.2","0.1","0"))

value looks like numbers, why are you converting it to a factor?

>
> My values go from 0 to 1 (might go slightly over the limits) and I want to
> specify one color for the following ranges, 1, 0.9,0.8,.....,0 .  That means
> that values between the intervals will be "categorized" based on their
> closest match.

I don't really understand this.

> What I also tried is to create a gray scale pallete as this is printer
> friendly so the values from 0.9 to 0.1 get a greyish tone but I failed to do
> that with colours.

How about

ggplot(tdm, aes(x = Var2, y = Var1, fill = value)) +
  labs(x = "MHz", y = "Threshold", fill = "Duty Cycle") +
  geom_raster(alpha=.5) +
  scale_fill_gradient(low="gray90", high="black") +
  theme_bw()

>
> Could you please help me have both
> a. A fixed scale where values are categorized there
> and

Value is numeric, and trying to treat it like a category is only going
to make things difficult.

> b. a greyish pallete for the categories?

Use scale_fill_gradient with different shades of gray as the low and
high values, as shown above.

Best,
Ista

>
> I would like to thank you in advance for your reply
>
> Regards
> Alex
>
>
> ________________________________
> From: Ista Zahn <istazahn at gmail.com>
> To: Alaios <alaios at yahoo.com>
> Cc: R help <R-help at r-project.org>
> Sent: Wednesday, February 20, 2013 4:54 PM
> Subject: Re: [R] ggplot2 customizing a plot
>
> Hi,
>
> On Wed, Feb 20, 2013 at 9:33 AM, Alaios <alaios at yahoo.com> wrote:
>> Dear all,
>> I want some help improve my ggplot as following:
>> Make the plottable area with grid, so is easy one to see where each box
>> refers to x and y values.
>
> I don't think you can easily move the grid to the front, but you can
> make the tiles transparent so the grid can be seen through them by
> setting the alpha < 1.
>
>> Add a color bar but with fixed values, that I want to specify.
>
> use scale_fill_manual
>
>> How  I can do those two?
>
> p<- ggplot(tdm, aes(x = Var2, y = Var1, fill = factor(value))) +
>   labs(x = "MHz", y = "Threshold", fill = "Duty Cycle") +
>   geom_raster(alpha=.5) +
>   scale_fill_manual(values=c("red", "blue", "green", "purple",
> "orange", "pink", "tan", "violet", "yellow"))
>
>
> Best,
> Ista
>
>
>>
>> Before is some code what I have tried so far.
>>
>> Regards
>> Alex
>>
>>
>> DataToPlot<-matrix(data=seq(1:9),nrow=3,dimnames=list(seq(1,3),seq(4,6)))
>>
>>
>> require(reshape)
>> require(ggplot2)
>> require(raster)
>>
>>  tdm <- melt(DataToPlot)
>>
>>
>>
>> p<- ggplot(tdm, aes(x = Var2, y = Var1, fill = factor(value))) +
>>            labs(x = "MHz", y = "Threshold", fill = "Duty Cycle") +
>>            geom_raster() +
>>            scale_fill_discrete()
>>
>>        [[alternative HTML version deleted]]
>>
>>
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>
>