search for: graph2nb

...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(Presabs ~Age+Curv+Zon2005+ZoneMeiji+Wi+Sol+Sl...

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]]

...distance 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 sh...

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. W...

Hi R helpers, Is there a function (package?) in R available which tests "spatial autocorrelation" between points (e.g. vector layer of weather stations)? (e.g. Moran's I...) Via the archives we found out that there is a package 'spdep' which uses grid data for testing spatial autocorrelation. Thanks a lot, Jan