I have three data sets with the same number of points, that each represent the period from high tide to low tide, with a data set corresponding to data from a given day. The data is aligned so that high tide for all three is the same data point, and low tide is the same data point, but these occur at different times of day. 30 data points covers 1 hour.
I want to label the x-axis as HT, HT+1 (to denote 1 hour after high tide), HT+2 (to denote 2 hours after high tide) etc but have no idea how to do this, and can't succinctly describe what I'm trying to do so I'm struggling to find information when I search. Does anyone have any guidance or knowledge about how to do this?