Please keep discussion on the mailing list.

On 22/08/2016 12:08 PM, Tomas Bayer wrote:
Hello,
we have tried the pre-processing till now but also with this error message:

akima.li <- interp(x, y, F, xo=seq(min(x), max(x), length = 100),
yo=seq(min(y), max(y), length = 100))
Error: could not find function "interp"

We have tried the same with interp.old and interp.new.
We also got the same error message by packages akima and rgl although they
are installed (confirmed by apt and synaptic, too).
Till now, all interpolation routines have failed.
What would we use as the ideal preparation to persp and contour?

If you are using the interp() function from the akima package, it appears you didn't attach it. Use

library( pkg )

to attach a package named "pkg". You may need to install the package first; use

install.packages("akima")

if so.

The variable name F may cause you problems: many people use F as an abbreviation for FALSE; it's a standard variable defined in the base package. It's a good idea to avoid masking that and causing yourself confusion later.

If this advice doesn't fix your problem, then please post a reproducible example for others to try. You might want to select a subset of your data if it's too big or too private to post here.

Duncan Murdoch


Thanks,

Tomas Bayer

On 22/08/2016 11:17 AM, Tomas Bayer wrote:
Hello,
when I plotted non-equidistant data in 3D (using persp and contour), it
was ended with the same error message:

persp(y, x, z, xlab="latitude", ylab="longitude", zlab="altiude",
main="Altitude")
Error in persp.default(y, x, z, xlab = "latitude", ylab = "longitude",
:
  increasing 'x' and 'y' values expected

How to fix it? The original data are in columns

 50.84925    14.65715 614.0  48909.14   -62.49  99  48929  5  122306
 50.84919    14.65702 617.0  48816.32  -145.82  69  48836  6  122331
 50.84908    14.65681 622.0  49113.40     6.64  99  49133  4  122442

You haven't shown us what is in y, x and z, but it looks as though you
haven't got data in the form required by persp, i.e. a vector of
increasing values in each of the first two arguments, and a matrix of
values in the third.  Using your variable names, you'd want z[i,j] to
correspond to y[i] and x[j].

If you just have a collection of (y, x, z) triples, you'll need to do
some pre-processing to fit a surface and produce the required inputs.

Duncan Murdoch




Tomáš Bayer
  ,           ,
 /             \
((__-^^-,-^^-__))
 `-_---' `---_-'
  `--|o` 'o|--'
     \  `  /
      ): :(
      :o_o:
       "-"
GNU's Not Unix!



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