How can i make the breaks on a logarithmic axis come in automatic/even intervals?-CodePudding

i am currenctly plotting a lot of graphs with two different y-axis, where the second one is log transformed. However, for now i am manually setting the breaks and it would be a great help if there were someway to automatically set the breaks so it looks nicer and with natural spacing? (or if there is a better way to log transform the second axis?)

coeff<-1/80000
p1<-ggplot(lf_test, aes(x=time))  
  geom_smooth(aes(y=normalized_gfp),size=2, span=0.3,fill = "#90d850", color = "#00BA38") 
  geom_smooth( aes(y=od / coeff), size=2, span=0.26,color="tomato",fill="tomato")     
  scale_y_continuous(limits = c(0,80000),
                     name = "Relative Flourescence [RFU]/[OD] ",
                     sec.axis = sec_axis(~ 10^(.x*coeff)-1, breaks = c(0.01,0.25,0.5,0.75,1,1.25,1.5,1.75,2.0,2.5,5.0,7.5,10.0,15.0,20.0), name = 'OD600')) 
  theme_grey()  
  theme(
    axis.title.y = element_text(color = "#90d850", size=13),
    axis.title.y.right = element_text(color = "tomato", size=13)
  ) 
print(p1)

My current code and plot looks like this:

Which is derived from a snippet of my dataset that looks like this:

     time          media id   od  gfp normalized_gfp
180 21.36 IO CasA Fe_gfp  1 0.21 1839       8757.143
181 21.36 IO CasA Fe_gfp  2 0.25 4363      17452.000
182 21.36 IO CasA Fe_gfp  3 0.53 2204       4158.491
183 21.60 IO CasA Fe_gfp  1 0.22 1966       8936.364
184 21.60 IO CasA Fe_gfp  2 0.28 4517      16132.143
185 21.60 IO CasA Fe_gfp  3 0.54 2302       4262.963
186 22.08 IO CasA Fe_gfp  1 0.24 2084       8683.333
187 22.08 IO CasA Fe_gfp  2 0.31 4659      15029.032
188 22.08 IO CasA Fe_gfp  3 0.56 2395       4276.786
189 22.32 IO CasA Fe_gfp  1 0.25 2209       8836.000
190 22.32 IO CasA Fe_gfp  2 0.34 4953      14567.647
191 22.32 IO CasA Fe_gfp  3 0.57 2484       4357.895
192 22.56 IO CasA Fe_gfp  1 0.27 2323       8603.704
193 22.56 IO CasA Fe_gfp  2 0.38 5305      13960.526
194 22.56 IO CasA Fe_gfp  3 0.59 2687       4554.237
195 23.04 IO CasA Fe_gfp  1 0.27 2450       9074.074
196 23.04 IO CasA Fe_gfp  2 0.41 5588      13629.268
197 23.04 IO CasA Fe_gfp  3 0.60 2886       4810.000
198 23.28 IO CasA Fe_gfp  1 0.28 2664       9514.286
199 23.28 IO CasA Fe_gfp  2 0.44 5713      12984.091
200 23.28 IO CasA Fe_gfp  3 0.61 2993       4906.557

I hope anyone can help, thank you very much in advance! :)

CodePudding user response：

Transform your left axis breaks using the same function:

library(ggplot2)

coeff<-1/80000
ggplot(lf_test, aes(x=time))  
  geom_smooth(aes(y=normalized_gfp),size=2, span=0.3,fill = "#90d850", color = "#00BA38") 
  geom_smooth( aes(y=od / coeff), size=2, span=0.26,color="tomato",fill="tomato")     
  scale_y_continuous(
    limits = c(0,80000),
    name = "Relative Flourescence [RFU]/[OD] ",
    sec.axis = sec_axis(
      ~ 10^(.x*coeff)-1 ,
      breaks = 10^(seq(0, 8e4, by = 2e4) * coeff) - 1,
      name = 'OD600'
    )
  )  
  theme_grey()  
  theme(
    axis.title.y = element_text(color = "#90d850", size=13),
    axis.title.y.right = element_text(color = "tomato", size=13)
  )