[R] Help with color.scale {plotrix}

[Kumar Mainali]

Hi Sarah,

Thanks for the explanation. This solves my first problem. I hope somebody
will be able to answer my second question. Copied here from previous email
>>

Another question: some of my matrices have missing cells and I do not want
to assign any colors to the missing cells. The following code gives me
error. I am trying to use the output (cellcol) to the
function color2D.matplot.

> cellcol<-matrix("#000000", nrow=nrow(plotdata),ncol=ncol(plotdata))
> cellcol[x<0.33]<-color.scale(x[x<0.33],c(1,0.8),c(0,0.8),0, na.color=NA)
Error in cellcol[x < 0.33] <- color.scale(x[x < 0.33], c(1, 0.8), c(0,  :
  NAs are not allowed in subscripted assignments
In addition: Warning messages:
1: In min(x) : no non-missing arguments to min; returning Inf
2: In max(x) : no non-missing arguments to max; returning -Inf
ᐧ

Postdoctoral Associate
Department of Biology
University of Maryland, College Park

On Fri, Oct 9, 2015 at 11:48 AM, Sarah Goslee <sarah.goslee at gmail.com>
wrote:

> Hi Kumar,
>
> You're overthinking it:
>
> in RGB, colorspace, cs1 is red, cs2 is green, cs3 is blue.
> So if cs1=c(1,1),cs2=(c(0,1),cs3=0 (or c(0,0) because of R's recycling)
> the first color in the sequence is c(1, 0, 0) or red ##FF0000 and the
> second color is c(1, 1, 0) #FFFF00 or yellow.
>
> Sarah
>
> On Fri, Oct 9, 2015 at 11:16 AM, Kumar Mainali <kpmainali at gmail.com>
> wrote:
> > Hi Jim,
> >
> > Thank you! Your color code does work. I still do not understand how red
> to
> > yellow in RGB space translates to cs1=c(1,1),cs2=(c(0,1),cs3=0. In other
> > words, I have RGB values for red and yellow. How do I go from there to
> the
> > code you sent?
> >
> > Another question: some of my matrices have missing cells and I do not
> want
> > to assign any colors to the missing cells. The following code gives me
> > error. I am trying to use the output (cellcol) to the
> > function color2D.matplot.
> >
> >> cellcol<-matrix("#000000", nrow=nrow(plotdata),ncol=ncol(plotdata))
> >> cellcol[x<0.33]<-color.scale(x[x<0.33],c(1,0.8),c(0,0.8),0, na.color=NA)
> > Error in cellcol[x < 0.33] <- color.scale(x[x < 0.33], c(1, 0.8), c(0,  :
> >   NAs are not allowed in subscripted assignments
> > In addition: Warning messages:
> > 1: In min(x) : no non-missing arguments to min; returning Inf
> > 2: In max(x) : no non-missing arguments to max; returning -Inf
> > ᐧ
> >
> > Postdoctoral Associate
> > Department of Biology
> > University of Maryland, College Park
> >
> > On Fri, Oct 9, 2015 at 7:24 AM, Jim Lemon <drjimlemon at gmail.com> wrote:
> >
> >> Hi Kumar,
> >> The color.scale function translates numeric values into one or more
> >> intervals of color by a linear transformation into the numeric values
> that
> >> specify colors. One of three color spaces (rgb, hcl and hsv) can be
> >> specified, and the endpoints can be specified as "extremes=c(<minimum
> >> color>,<maximum color>" or as three vectors of numbers. By default, the
> RGB
> >> color space is used, so:
> >>
> >> # starts at RGB #FF0000 and finishes at RGB #FFFF00
> >> red to yellow - extremes=c("red","yellow") OR
> cs1=c(1,1),cs2=(c(0,1),cs3=0
> >> # starts at RGB #FFFF00 and finishes at RGB #00FF00
> >> yellow to green - extremes=c("yellow","green") OR
> >> cs1=c(1,0),cs2=(c(1,1),cs3=0
> >>
> >> Obviously the shades of colors that you want may differ from the above,
> so
> >> you have to play with the values to get the ones you want. In many
> cases,
> >> you will have to specify more than two numbers for the color specs to
> get
> >> the "in between" colors right, especially if the span of the colors is
> >> large.
> >>
> >> Jim
> >>
> >> On Fri, Oct 9, 2015 at 4:15 PM, Kumar Mainali <kpmainali at gmail.com>
> wrote:
> >>
> >>> Hi Jim and others:
> >>>
> >>> I needed color code for some color gradients in color.scale function. I
> >>> found that the following translates to green to yellow to
> >>> red: c(0,1,1),c(1,1,0),0. How does this string translate to the color
> >>> gradient? I would like to know the gradient code for red to yellow,
> yellow
> >>> to green and other ranges.
> >>>
> >>> Thanks,
> >>> Kumar Mainali
> >>>
>

	[[alternative HTML version deleted]]