I am new to R programming. I am currently working on a research project that can improve mstree() in spdep package. I have a question on how to make Polygon(), Polygons(), SpatialPolygons(), and SpationPolygonsDataFrame() to work. Below are the codes I tried:
library("spdep")
library("sp")
require(maptools)
Dmat<-matrix(nrow=1,ncol=2)
rownames(Dmat)<-c("s1")
Dfram<-data.frame(Dmat)
#diabetesNum is a dataset that I artificially made
nrows<-nrow(diabetesNum)
x1matrix<-data.matrix(diabetesNum)
x1Frame<-data.frame(diabetesNum)
x1Frame4<-as(x1Frame,"S4")
x1X<-prcomp(x1Frame)$x
#Use the first two principal components for coordinates of the points
xycoordinates<-data.frame(x1X[,1:2])
row1<-xycoordinates[1,]
row1M<-data.frame(row1)
xycoordinates[nrows+1,]<-c(row1M)
xycoordinates
PC1 PC2
1 285.60120 -6.541733
2 -78.14211 -30.160212
3 -263.15002 31.236614
4 51.00528 -143.520521
5 -139.55849 27.842465
6 -244.09755 31.258001
7 281.18411 12.072960
8 580.64105 51.538605
9 -135.05802 -38.923404
10 -201.08445 47.932800
11 -137.34100 17.264425
12 285.60120 -6.541733
xycoordinatesF<-data.frame(xycoordinates)
xycoordinatesM<-data.matrix(xycoordinatesF)
pl<-Polygon(xycoordinatesM)
pls<-Polygons(list(pl), ID="1")
Sr<-SpatialPolygons(list(pls))
bho.nb<-poly2nb(Sr)
Error in sp$mbxv[i]:(n * 2) : argument of length 0
...and ERROR! what is the wrong with my code above? I searched and searched on the internet to find out the proper way to use Polygon(), Polygons(), SpatialPolygons(), SpatialPolygonsDataFrame(), and poly2nb() yet I just don't know how to make these functions work! I already have gone through R manual but it is not so much of helpl...... one interesting thing though is that when I view the Polygons object, the Polygons slot is empty; when I view Sr, similarly, the SpatialPolygons slot and Polygons slot are empty. thanks,
