Creating a timeline based on years in R

Question

I am fairly new to coding with R. I am working with relatively easy data just a large amount of it. I am trying to create a timeline based on the years these species of whale were sighted. So I just have two variables (year and species) and 151 observations. There are a total of 25 species to plot on this time line and I have provided a small example of my data below.

year       species
1792    Megaptera novaeangliae
1792    Physeter macrocephalus
1793    Physeter macrocephalus
1832    Physeter macrocephalus
1833    Physeter macrocephalus

I have tried creating the timeline using timelineS and timelineG as well as vistime. TimelineG gets close to creating what I want but it does not seem to plot anything. The code is as follows:

timelineG(t8, start="year", end="year", names="species")

timelineG results

I am just kind of stuck. I do have the month and day that the species were sighted so I can add that back if needed. Thank you in advance for any guidance.

Answer 1

or like this using timelineg,

dta <- data.frame(species = c('Megaptera novaeangliae','Physeter macrocephalus',
                              'Physeter macrocephalus','Physeter macrocephalus',
                              'Physeter macrocephalus'),
                  year = c(1792,1792,1793,1832,1833))

#str(dta)
dta$year <- as.Date(ISOdate(dta$year, 1, 1)) # assuming beginning of year for year 
# str(dta)


timelineS(dta, main = "BGoodwin's species example")