[R] persp fail with non-equidistant dates

[Duncan Murdoch]

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