On 07.02.2010 22:46, Andrew Wang wrote:
I have this data set that both x& y are ordered vectors of length 600& 700
respectively; z is a 600 by 700 matrix whose entry z[i,j] is either a missing value
(indicated by 'NaN') or a real number between 0 and 1. The contour function
contour(x,y,z)
gives me a blank picture. I guess the reason is that most of z-entries are
missing, only less than 1% are non missing.
Question (1)
Is there a way that I could manipulate the data or function to have the
non-missing values plotted?
Also, trying function "persp" gives me this error message
persp(x,y,z)
Error in persp.default(x, y, z) : invalid 'z' limits
I look at the manual of "persp". I guess, the error message comes from its
internal call
zlim = range(z, na.rm = TRUE)
it appears to me that "persp" can't handle missing value yet its manual states
clearly
z: a matrix containing the values to be plotted ('NA's are
allowed). Note that āxā can be used instead of āzā
for convenience.
Question (2)
Can "persp" handle missing values in z? if the answer is a sounding "yes", how
should I do in my case?
Works for me:
persp(1:2, 1:2, matrix(c(1:3, NA), nrow=2))
Hence you really need to specify an example where it does not work.... -
as the posting guide asks you to do anyway.
Uwe Ligges
Please help, Thanks!
Your frustrated
Andrew
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______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.