tab <- read.table("base_at_part.txt", header=T, sep="\t")
tab
dim(tab)
names(tab)
summary(tab)

plot(tab$WGS84_E,tab$WGS84_N, col="blue", xlab="WGS84 E", ylab="WGS84 N")

#points(tab, pch=21, col="red", bg="yellow", cex=0.5)
#text(tab, "Status==casual", col="red", cex=0.5)

#densité histogramme années
hist(tab$year_record, 
     probability=TRUE, breaks=20, col="light blue")
points(density(tab$year_record, bw=1),  type='l', lwd=3, col='black')

#density (kernel density estimation)
library(MASS) 
kde2d(tab$WGS84_E,tab$WGS84_N) -> tmp 
filled.contour(tmp, color.palette = topo.colors)
tmp
?kde2d