Hmm yes that is what I'm looking for in terms of color scale control, but I
need it for contoured plots.  John.

On Mon, Mar 22, 2010 at 10:32 PM, Jim Lemon <jim@bitwrit.com.au> wrote:

> On 03/23/2010 12:48 PM, John K. Williams wrote:
>
>> Hello, I'm having some trouble getting things to look as I want with
>> filled.contour.
>>
>> 1.  My first issue is that I am unable to add line segments to my plot
>> where
>> I want them.  Using the rug pattern example:
>> x<- y<- seq(-4*pi, 4*pi, len = 27);
>> r<- sqrt(outer(x^2, y^2, "+"));
>> filled.contour(cos(r^2)*exp(-r/(2*pi)));
>> segments(0.2,0.2,1,0.2);
>> The line segment is not found in relation to the x-axis but is seemingly
>> squished over by the color bar.
>>
>> If I try to achieve the line this way:
>>
>> filled.contour(cos(r^2)*exp(-r/(2*pi)),plot.axes={lines(c(0.2,1),c(0.2,0.2))})
>> Now when I add the axis back it is misaligned.
>> axis(1).
>>
>> 2. Secondly I'm finding the literature difficult to understand on how to
>> make a nice color scheme.  Below is a nice scheme I found from an example,
>> except I don't understand why the scale seems to cycle into blue again for
>> larger values, even though I think I am setting the number of levels of
>> colors and contour levels to be equal.  Basically I want reds for the
>> highest values and blues for the lowest:
>>
>> filled.contour(cos(r^2)*exp(-r/(2*pi)),nlevels=25,col=hsv(h=seq(from=.7,to=0,length=25)))
>>
>> 3.  I'm used to working with matlab where it was simple to make the color
>> scale the same on multiple figures using caxis().  However I don't see
>> this
>> option for filled.contour (possibly it exists for levelplot() but I was
>> having even less success understanding that one).  I only see the option
>> to
>> set the number of levels which doesn't really accomplish what I want for
>> plots that are going to have widely varying limits.
>>
>>  Hi John,
> I'm not sure that this is what you want, but the examples for the barp
> function in the plotrix package include one for a color scale that extends
> beyond the values that are to be plotted. That is, you can specify the range
> of the color scale regardless of the actual values.
>
> Jim
>
>

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