Compare:
persp(matrix(c(1,1,NA,NA,
1,1,NA,NA,
1,NA,NA,NA,
1,NA,NA,1), 4,4), zlim=c(0,2))
persp(matrix(c(1,1,0,0,
1,1,0,0,
1,0,0,0,
1,0,0,1), 4,4), zlim=c(0,2))
--
David.
On Feb 15, 2013, at 12:01 PM, David Winsemius wrote:
>
> On Feb 15, 2013, at 1:14 AM, jas wrote:
>
>> Hello David,
>> thanks again for your reply.
>>
>> Two things remain unclear. That the data is disjointed is ok, as there are
>> only values in hectares, where there are actually buildings and stuff,
>> forest/nature is NA.
>>
>> The presp-scan that I get from persp(grd) has no similarity to the image in
>> 2d. My guess is that the order and regularity in the data somehow gets lost
>> in the process of making the matrix?!
>
> I think the disjointedness is the problem. There are many values where there
> is no adjacent value in one direction of another and so no tessellation can
> be formed. If you look at the image result and note the places where there
> are "solid values" in both x and y directions I think the overall patterns
> match up. The image result is more faithful to the data.
>
>>
>> The grid-extraction that I uploaded contains 40x20 cells. if its a bigger
>> grid with 7million cells, does it still work the same way or can the vectors
>> only be a maximum of 100 cells?
>
> Might be a performance problem although I don't think it is theoretically
> impossible. An 8000 x 8000 matrix consumed my full CPU resources and
> essentially locked up my session. I'm in the process of deciding when to halt
> it.
>
> Are you aware that there are far more knowledgeable persons than I that hang
> out at the R-SIG-Geo list?
>
> --
> David
>
>>
>> Thank you for your help
>> jas
>>
>>
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/3D-plots-of-2D-grids-tp4658517p4658639.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> David Winsemius
> Alameda, CA, USA
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
David Winsemius
Alameda, CA, USA
______________________________________________
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