I am looking for a way in ggplot to plot an historic line of data which then merges into a shaded area representing future uncertainty (like the GHG emissions graphs below - but at the moment I just want one trajectory into the future - and even then based simply on straight lines).
This is the historic data line I want:
Quarter historicData
1: 2022Q3 1.91626
2: 2022Q2 1.78145
3: 2022Q1 1.66113
4: 2021Q4 1.47459
I then want to have a "wedge" going from a single point of 1.91626 at 2022Q3, spreading to a maximum of 47 and a minimum of 37 at 2029Q4
I have looked at geom_ribbon but this appears only to do a constant width?
Could anyone help me please? Many thanks, Tim
