How can I create a raster layer with filled circles centered in "c(df$lat,cd$lon)" and radius "df$radius" from a dataframe?
df <- data.frame(lat=c(40.4,42.4,42.4,42.4,42.3),
lon=c(-0.3,1,1.5,2.7,2.1),
radius=c(4.4,8.4,11.4,5.4,10.3))
df
# lat lon radius
# 40.4 -0.3 4.4
# 42.4 1.0 8.4
# 42.4 1.5 11.4
# 42.4 2.7 5.4
# 42.3 2.1 10.3
library(dismo)
df <- data.frame(lat=c(40.4,42.4,42.4,42.4,42.3),
lon=c(-0.3,1,1.5,2.7,2.1),
radius=c(4.4,8.4,11.4,5.4,10.3))
Note the use of lon/lat, not lat/lon
p <- df[,2:1]
The radius is in meters so your numbers are very small. I'll change them
rad <- df[,3]*2500
Compute circles
cc <- circles(p, rad, lonlat=TRUE, dissolve=FALSE)
plot(cc)
points(p)
Get the polygons
pls <- polygons(cc)
To get a RasterLayer you can either use predict(cc, ) or rasterize(pls, )
r <- raster(extent(pls), res=.01)
pr <- predict(cc, r)
(if you do not want the overlaps to be counted, use dissolve=TRUE in the circles function)