search for: gabrielneigh

...in C... I am using Ubuntu 9.04 and R version 2.8.1 . The code in R is a fallows: taimin.xy = taimin[c("dy", "dx")]; coordinates(taimin.xy) <- ~dy+dx; #dy, dx, name of the respective coordinate columns coords<-coordinates(taimin.xy); library(spdep); TaiminGabrielGraph<-gabrielneigh(coords, nnmult = 12); tai.gab.nb<-graph2nb(TaiminGabrielGraph,sym=TRUE); nbtaim_distsg <- nbdists(tai.gab.nb, coords); nbtaim_simsg <- lapply(nbtaim_distsg, function(x) (1-((x/(4*50))^2)) ); MEtaig.listw <- nb2listw(tai.gab.nb, glist=nbtaim_simsg, style="B"); sevmtaig <- ME...

Hi group, I'd like to do spatial analysis of my data using the spdep package. It appears that a file of class nb is necessary, but I do not find what that should look like and if there is a function that creates such file for me. How can I create a nb-object of my data points? Thanks, René Eschen. [[alternative HTML version deleted]]

...matrix based on a nb object created by spdep where sites must have a larger influence in one direction then in the other. Here is an example to better illustrate what I need: Let say I have the following Gabriel connection network library(spdep) library(ade4) data(orbatid) nbgab<-graph2nb(gabrielneigh(as.matrix(oribatid$xy))) plot(nbgab,oribatid$xy) text(oribatid$xy,as.character(1:70),pos=1) # site number arrows(-0.3,0,-0.3,10) # gradient direction In that example, site 1 shouldn't influence site 2 (so it should have a distance if 0 in the distance matrix). However site 1 should influen...

Dear list, following the vignette of the package 'spacemmakeR' I have built a gabriel graph of ten randomly placed points: library(spdep) set.seed(3) xyir<-matrix(runif(20),10,2) nbgab<-graph2nb(gabrielneigh(xyir), sym=TRUE) plot(nbgab,xyir,points=FALSE) points(xyir,pch=20,cex=2,col=c(2,4,4,4,2,2,4,2,4,4)) title(main="Gabriel Graph") Now, I need to determine for any additional point whether it is located within the region surrounded by links between identically colored points. Would anybody...

hi,friends, we all know that moran's I index and Geary'C index can be used to test spatial autocorrelation in both the area data and point data, but i only can find something on how to calculate on the data of area, and can't find the methods to perform it on the point data, could anybody give me some information, thanks in advance! -- Kind Regards, Zhi Jie,Zhang ,PHD Department of