Question

When missing data is present or there is a large gap in the dates, ggplot produces a discontinuous line.

Eg:

    q.data<-structure(list(date = structure(c(15544, 15546, 15547, 15548, 
15550, 15552, 15554, 15556, 15575, 15580, 15587, 15588, 15589, 
15593, 15596), class = "Date"), data = c(NA, 0.2, 0.2, 0.3, 0.6, 
0.7, 0.8, 0.9, NA, NA, 1, 1, 1.1, 1.7, 2)), .Names = c("date", 
"data"), row.names = c(NA, -15L), class = "data.frame")

q.data$date<-as.Date(q.data$date, format="%Y-%m-%d")

q.plot<-qplot(data=q.data,
              x=date,
              y=data)+geom_line()

print(q.plot)

I am looking for a way to force a continuous line.

Answer 1

I don’t think it really happens with a large gap in the dates, in the absence of NAs. The NA values seem to be your problem.

I think

q.plot <- qplot(data=na.omit(q.data),...) 

should work, but what I tried (which worked) was

print(q.plot %+% na.omit(q.data))

PS: 1. it would be slightly nicer to use dput to post your data. 2. My solution also gets rid of NA values at the beginning and end of the series, which could conceivably be problematic …