如何在ggplot2中的facet_wrap函数上指定时间间隔轴？

Question

I am using this package for data analysis: https://cran.r-project.org/web/packages/wq/vignettes/wq-package.html

And the section for plotTs uses facet_wrap function in ggplot2 , the example has a 5 year interval breakdown on automatic. My data is only 17 years, so my intervals are very useless with 5 year plots. First year is 1996 and last 2013, so is there to specify the breakdown of intervals specific to my case?

plotTs(y[, 1:4], dot.size = 1.3, ylab = "Chlorophyll in San Francisco Bay",
      strip.labels = paste("Station", 21:24), ncol = 1, scales = "free_y")

Answer 1

Since wq is using ggplot2, you could use scale_x_date() . Consider this:

data(sfbay)
sfb <- wqData(sfbay, c(1, 3:4), 5:12, site.order = TRUE,
               type = "wide", time.format = "%m/%d/%Y")

y <- tsMake(sfb, focus = "chl", layer = c(0, 5))
y[1:4, ]
plotTs(y[, 1:4], dot.size = 1.3, ylab = "Chlorophyll in San Francisco Bay",
       strip.labels = paste("Station", 21:24), ncol = 1, scales = "free_y") + 
scale_x_date(date_breaks = "7 years", date_labels = "%Y")

you can play with date_breaks() and date_labels . For more information on scale_x_date() see http://docs.ggplot2.org/current/scale_date.html