[R] how to change my data to "point data set" in package "SPLANCE"?

[Roger Bivand]

On Sat, 25 Feb 2006, zhang jian wrote:

> Hi!
> I want to use the package "SPLANCE" to do Ripley's K analysis
> I have a basic question about the package.
> I try to find how to do it, but I cannot.

You asked the same question with reference to the spatial package 
associated with MASS last week, and have now asked this one twice. I 
replied to your question about spatial, but have not seen any comment 
from you on that solution. Perhaps your best choice is to study the 
literature of the subject more closely, next to try to learn something of 
how data are represented in R, and when you have done that, and if you 
still have difficulties, ask again. 

Note that the help pages do explain carefully how the functions should be
used, with examples that are documented in the cited references. Please do
try to use the documentation provided with these packages.

Hint: it appears that qumo is a data frame. You can extract the 
coordinates in many ways. Data frames are also seen as lists, and since 
your data frame has coordinates named "x" and "y", the splancs function 
as.points() will work:

library(splancs)
xy <- data.frame(x=rnorm(50), y=rnorm(50))
pxy <- as.points(xy)
plot(pxy)
plot(khat(pxy, sbox(pxy), s=seq(0,2,0.1)), type="l")


> I hope you can help me.
> I donot know how to change my data form to "point data set".
> my data form is:
> > qumo[1:5,]
>      code species  dbh     x      y   tag status branch
> 223 10312    QUMO 54.5  7.83  44.80 10306  alive      0
> 252 10331    QUMO 48.8 11.44  51.05 10333  alive      0
> 346 10424    QUMO 67.0 14.30  69.68 10443  alive      0
> 395 10511    QUMO  7.8  3.10  83.83 10503  alive      0
> 491 10613    QUMO 57.1  9.12 107.00 10607  alive      0
> "x""y" is the coordinate.
> 
> And I think "xl   xu   yl   yu" equl to  "0  500  0  500"
> it is a square.
> 
> Can you help me?
> Thank you very much.
> 
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no