[R] Minor tick marks for date/time ggplot2 (this is better, but not exactly what I want)

[hadley wickham]

On Mon, Jun 1, 2009 at 2:18 PM, stephen sefick <ssefick at gmail.com> wrote:
> library(ggplot2)
>
> melt.updn <- (structure(list(date = structure(c(11808, 11869, 11961, 11992,
> 12084, 12173, 12265, 12418, 12600, 12631, 12753, 12996, 13057,
> 13149, 11808, 11869, 11961, 11992, 12084, 12173, 12265, 12418,
> 12600, 12631, 12753, 12996, 13057, 13149), class = "Date"), site =
> structure(c(1L,
> 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L,
> 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L), .Label = c("unrestored",
> "restored"), class = "factor"), value = c(1.10799962473684, 0.732152347032395,
> 0.410438861475827, 0.458941230025228, 0.429883166858706, 0.831083728521569,
> 0.601942073736539, 0.81855597155132, 1.12612228239269, 0.246006569972335,
> 0.940239233910111, 0.98645360143702, 0.291191536260016, 0.346271105079473,
> 1.36216149279675, 0.878585508942967, 0.525184260519839, 0.803247305232454,
> 1.08086182748669, 1.24915815325761, 0.971046497346528, 0.936835411801682,
> 1.26957337598606, 0.337691543740682, 0.90931142298893, 0.950891472223867,
> 0.290354002109368, 0.426509990013021)), .Names = c("date", "site",
> "value"), row.names = c(NA, -28L), class = "data.frame"))
>
> #I would also like to add tick marks to this graph is possible with no
> label for the months in between the years
> qplot(date, value, data=melt.updn, shape=site, ylab="Distance"
> ,main="Euclidean Distances Time Series", xlim=c(as.Date("2002-1-1"),
> as.Date("2006-3-1")))+geom_line()+theme_bw()+geom_vline(x=as.numeric(as.Date("2002-11-01")))
> + opts(panel.grid.major = theme_line(colour="grey", size=0.75),
> panel.grid.minor=theme_line(colour="grey", size=0.25))

Unfortunately that's currently not possible - tick marks are always
associated with major grid lines, and more importantly currently
scale_date only lets you specify the time between ticks, not their
labels.  Are the minor monthly grid lines not good enough?

Hadley

-- 
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