# [R] persp Error. x,y,z with the same length

Greg Snow Greg.Snow at intermountainmail.org
Wed Apr 11 18:07:44 CEST 2007

``` x and y should be vectors with the coordinates, z should be a matrix
with the heights at the combination of those coordinates.  If x and y
are properly gridded in your dataset, then try something like:

> h   <- Measure3[,4]
> x   <- sort(unique(Measure3[,3]))
> y   <- sort(unique(Measure3[,2]))
> z <- matrix( h, ncol=length(x) )
> persp(x,y,z)

Hope this helps,

--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Felix Wave
> Sent: Wednesday, April 11, 2007 8:56 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] persp Error. x,y,z with the same length
>
> Hello,
> I have a problem in drawing a 3d graphic. I simplified the
> program to show you the problem.
>
> I have a text file with hundreds of entries in 3 columns. I
> scaned these columns with matrix(scan). Then, I transformed
> some datas. Now I have the datas in h,x,y.
> I created a new matrix to use persp . But I got an error. The
> reason is probably the same length of x,y,z.
>
> But what can I do the draw my datas in a 3d graphic? (I want
> to use persp resp. image)
>
> Thanks a lot!
> Felix
>
>
> the code:
> ------------
> h   <- Measure3[,4]
> x   <- Measure3[,3]
> y   <- Measure3[,2]
>
> z   <- matrix(c(x,y,h),ncol=3)
> z
>
> persp(x, y, z)
>
>
> > z
>       [,1] [,2]        [,3]
>  [1,]  0.0    0 0.000000000
>  [2,]  0.1    0 0.000538990
>  [3,]  0.2    0 0.002315760
>  [4,]  0.3    0 0.005333315
>  [5,]  0.4    0 0.009595005
>  [6,]  0.5    0 0.015104450
>  [7,]  0.6    0 0.021865495
>  [8,]  0.7    0 0.029882130
>  [9,]  0.8    0 0.039158475
> [10,]  0.9    0 0.049698760
>
> Default in persp.default(x, y, z) : increasing 'x' and 'y'
> values expected
>
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