Re: [R-sig-Geo] Spatial simulation

2007-06-02 Thread Virgilio Gomez-Rubio
Dear Kitty, What I usually do when I want to generate a spatially varying variable is to generate some points at random in the study area and then do a kernel smoothing on those points. The values of my variable at (x,y) are the values of the kernel smoothing at that point. Hope this helps. Virg

Re: [R-sig-Geo] Spatial simulation

2007-06-02 Thread Terry Griffin
I conducted similar simulations using invIrM in the spdep package. Dr. Anselin has a nice tutorial entitled Spatial Regression Analysis in R, A Workbook ( http://www.sal.uiuc.edu/stuff/stuff-sum/pdf/rex1.pdf ) (90 pp., 456K) at http://www.sal.uiuc.edu/stuff/stuff-sum/tutorials where I began to

[R-sig-Geo] Spatial simulation

2007-06-02 Thread Kitty Lee
Yes, let me be more specific. Say I have two variables, X and Y. I know that at the individual level, the relationship between them is: Y=a + bX+ error I try to run some simulation where X is spatially clustered. I can generate spatially clustered points, e.g. nsp.u2<-pcp.sim(25,40,.001, sp