Raphaël Lavoie
2014-Mar-03 15:42 UTC
[R] Circular density estimate to a raster for mapping in GIS - help
Hi all, I created a circular density estimate using package "circular" from bearings (directions) from 0 to 360° assuming a von Mises distribution. ############# library(circular) Bearing<- c(186,197,158,206,206,185,186,224,183,173,175,240,201,197, 175,173,226,227,233,193,175,217,171,193,190,186,222,185, 208,194,230,184,223,183,190,229,228,234,187) circular(Bearing, type=c("angles", "directions"), units=c("degrees"), template=c("geographics")) plot(Bear <- circular(Bearing, type=c("angles"), units=c("degrees"), rotation = c("clock"), zero=1.570796), ticks=T, stack=T, bins=360, xlim=c(-2,1), ylim=c(-2,1)) mle.vonmises(Bear, mu=NULL, kappa=NULL, bias=FALSE, control.circular=list(units="degrees")) ## estimated (±SE) x <- rvonmises(n=39, mu=199.2, kappa=7.351, control.circular=list(units="degrees")) res25 <- density(x, bw=25, control.circular=list(units="degrees"), kernel="vonmises") circularp(res25$x) lines(res25, points.plot=F, xlim=c(-2,1)) ############# The output is probabilities that an object is going in a given direction (destination) from a specific location (origin). More specifically, there is a probability estimate for each direction (each 360 degree wedge). I would then like to create raster (0.5 x 0.5°) from that circular distribution with the center being the point of origin and the different directions displaying the underlying probabilities that an object is going in a direction (destination). Imagine a pie chart with 360 pie slices having each a specific probability. I tried to use the "raster" package, but can't figure out how to do it. Can anyone help? Thanks! Raph [[alternative HTML version deleted]]