base<- raster("test.tif")
plot(base)

breakpoints<-c(0,5,10,15,20,25)
plot(base, col=terrain.colors(6), breaks=breakpoints)

plot(base, col=colorRampPalette(c("red", "orange", "blue"))(6), breaks=breakpoints)

breakpoints<-c(0,5,10,15,20,25,50)
plot(base, col=colorRampPalette(c("red", "orange", "blue"))(7), breaks=breakpoints)

breakpoints<-c(0,5,10,15,20,25,50)
colors<-c("red", "orange", "blue","green","yellow","cyan","magenta")
plot(base, col=colors, breaks=breakpoints)