[R] cuts and breaks

Winfried Theis theis at statistik.uni-dortmund.de
Thu Sep 27 18:07:40 CEST 2001

On 27-Sep-01 José Ernesto Jardim wrote:
> Hi
> I'm using the "image" function to produce a plot and I want to define 
> the breaks using "cut" and the colors using "heat.colors".
>  > 
> rs(29))

> Error in image.default(interp(mat2[, 2], mat2[, 1], mat2[, 3]), breaks = 
> cut(mat2[,  :
>         must have one more break than colour
> The error message is not clear to me because I'm using 30 to cut and 29 
> to heat.colors.
> What am I doing wrong ?
I think you use the wrong function for your purpose: "cut" converts a numeric
vector into a factor with levels correponding to intervalls -- but here you
need to define the breakpoints for the intervalls for which each colour is
used. Something along the lines:


should do the trick.

Maybe you should check the functions you want to use first on their real

Cheers, Winfried

E-Mail: Winfried Theis <theis at statistik.uni-dortmund.de>
Date: 27-Sep-01
Time: 16:51:55
Dipl.-Math. Winfried Theis, Fachbereich Statistik, Graduiertenkolleg
"Angewandte Statistik"
Universität Dortmund, 44221 Dortmund
Tel.: +49-231-755-5903  FAX: +49-231-755-4387
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