MotaF - 1 year ago 92
R Question

# R plot,why is introducing of axis limits creating havoc?

My code

``````library(Hmisc)

p1=r1[1]
per1=log10(p1)
p2=r2[1]
per2=log10(p2)
p3=r3[1]
per3=log10(p3)
p4=r4[1]
per4=log10(p4)

m1=nrow(per1)
m2=nrow(per2)
m3=nrow(per3)
m4=nrow(per4)

xmin <- floor( min(per1,per2,per3,per4))
xmax <- ceiling( max(per1,per2,per3,per4))

lxmax=10^(xmax)
lxmin=10^(xmin)

rhoaxy = r2[3]
phaxy = r2[5]

rhoayx = r3[3]
phayx = r3[5]

rhoaxx = r1[3]
phaxx = r1[5]

rhoayy = r4[3]
phayy = r4[5]

per2=unname(per2)
per2=unlist(per2)
per3=unname(per3)
per3=unlist(per3)

rhoaxy=unname(rhoaxy)
rhoaxy=unlist(rhoaxy)
rhoaxy=log10(rhoaxy)
rhoayx=unname(rhoayx)
rhoayx=unlist(rhoayx)
rhoayx=log10(rhoayx)

ymin1=floor(min(rhoaxy)-1)
ymax1=ceiling(max(rhoaxy)+1)
ymin2=floor(min(rhoayx)-1)
ymax2=ceiling(max(rhoayx)+1)
ymin=min(ymin1,ymin2)
ymax=max(ymax1,ymax2)

png("withlim.png")

plot(per2,rhoaxy, col='red', xlab='Per (s)', ylab = 'Rho-xy/yx',ylim=c(ymin, ymax))
par(new=TRUE)
plot(per3,rhoayx, col='green', xaxt='n', xlab= NA, yaxt = 'n', ylab = NA)

dev.off()
``````

The image I got

If I delete ylim

My question is,why are the axis limits changing the image content?The values from the second image correspond to proper data values.The first image is with values that do not represent rhoaxy and rhoayx.

So you've got the superposition of 2 plot, with a different Y axis. If you want the same ylim on both plot, add `ylim=c(ymin, ymax)` on the second plot also.