[R] Beginner Question on Persp()

[Petr Pikal]

Hi

> x<-1:100
> y<-1:100
> z<-rnorm(100*100)
> dim(z)<-c(100,100)
> persp(x,y,z)

works ok
so problem is with your data. "Z" being OK in Minitab does not mean 
it is read OK to R.


On 5 Feb 2007 at 5:50, Tom H. wrote:

Date sent:      	Mon, 5 Feb 2007 05:50:34 -0800 (PST)
From:           	"Tom H." <tom.hatfield at ae.ctscorp.com>
To:             	r-help at stat.math.ethz.ch
Subject:        	[R] Beginner Question on Persp()

> 
> I recently downloaded R for Windows, running on Win XP.  I'm trying to
> create a perspective plot but not having any luck after reading the R
> manual and several examples found on the Internet.
> 
> I have a 100 x 100 matrix of Z data as a tab-delimited text file
> exported from Minitab.  I read this in to R using read.delim; this
> seemed to go ok. I created  X and Y using seq() to get 100 divisions

what does str(Z) says about your data?
z<-list(z)
> persp(x,y,z)
Error in persp.default(x, y, z) : (list) object cannot be coerced to 
'double'

so although z looks like matrix it is actually list

 z1<-z[[1]]
 persp(x,y,z1)

works again OK.

Based on structure of your data you need to extract a matrix for 
using it as z. See ?persp

HTH
Petr

BTW try to transfer it to R just by selection of data list in 
Minitab, pressing Ctrl-C, and using

z <-  read.delim("clipboard")

in R. It works for me.

> for the X and Y axes. Again, everything looked good, when I typed X or
> Y I got a string of 100 numbers.
> 
> However, when I try to do persp(x,y,z) I get an error something like:
> (list) cannot be coerced to double.  I know the basic data (matrix of
> z values) is ok (no hidden non-numeric values) because Minitab will
> graph it just fine. Any suggestions on how to proceed?  Thanks in
> advanced for your help. -- View this message in context:
> http://www.nabble.com/Beginner-Question-on-Persp%28%29-tf3174399.html#
> a8806483 Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
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> PLEASE do read the posting guide
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Petr Pikal
petr.pikal at precheza.cz