[R] persp plot increasing 'x' and 'y' values expected

[Duncan Murdoch]

On 4/25/2006 6:23 AM, Michael Dondrup wrote:
> Hi, 
> of course it can't because the number of unique values is different. You need 
> a unique _combination_ of x,y and hopefully you don't have different z values 
> for any such a pair. try:
> 
> xyz <- unique(cbind(x,y,z))
> persp(xyz)
> 
> If you still get the err, then you had different measurements for the same 
> point.

I think you and Andreas want scatterplot3d (from a contributed package 
of the same name), not persp.  Persp takes very data in a very 
particular format.  See the man page.

In general, it's a good idea to test your suggestions before posting 
them. Yours wouldn't work, because x, y and z *must not* be the same 
length in persp.

Duncan Murdoch

> 
> Am Tuesday 25 April 2006 12:24 schrieb voodooochild at gmx.de:
>> hi peter,
>>
>> thank you for your advice.
>> ok, i see the problem, but if i do
>>
>> x<-unique(data$x)
>> y<-unique(data$y)
>> z<-matrix(unique(data$z),length(y),length(x))
>>
>> it also doesn't work.
>>
>> i want to do a plot, where i can see, how x and y influences z.
>>
>> P Ehlers wrote:
>>> voodooochild at gmx.de wrote:
>>>> hello,
>>>>
>>>> i do the following in order to get an persp-plot
>>>>
>>>> x<-c(2,2,2,2,2,2,3,3,3,3)
>>>> y<-c(41,41,83,83,124,166,208,208,208,208)
>>>> z<-c(90366,90366,92240,92240,92240,96473,100995,100995,100995,100995)
>>>> x<-data$x
>>>> y<-data$y
>>>> z<-matrix(data$z,length(y),length(x))
>>>> persp(x,y,z, col="gray")
>>>>
>>>> but i always get the error message increasing 'x' and 'y' values
>>>> expected, but i think my data values are already increasing, what is
>>>> wrong?
>>> I'm not sure what your data$x, data$y, data$z are (but I can guess).
>>> Why do you think that your x is *increasing*? Is x[i+1] > x[i]?
>>> Does diff(x) yield only positive values?
>>>
>>> What kind of a perspective plot do you expect? You seem to have only
>>> 5 unique points.
>>>
>>> Peter Ehlers
>>>
>>>> best regards
>>>> andreas
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