[R] Help with color.scale {plotrix}

[Sarah Goslee]

Presumably you need something like
cellcol[x < 0.33 & !is.na(x)]
just as the error message suggests. I don't think it's a color.scale issue.
On Oct 9, 2015 3:27 PM, "Kumar Mainali" <kpmainali at gmail.com> wrote:

> 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
>> >>>
>>
>
>

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