I have a plot made of many samples, usually the sampling rate is 8 samples per seconds but it may be more or less. Each and every sample has a timestamp of course.
I have a UI in which I display the plot to the user. The user may asks for 10 years of data and I'm showing the complete plot on screen. Since the pixel width of the screen is limited (let's say 1000 pixels) the plot is just a rough representation of the real one.
This means that, on a very zoomed out plot, each pixel column represents more than 1 sample, it may represents a week worth of data with thousand and thousand of samples in it.
If the user point selects on a very zoomed out plot, which sample should be "selected"? Is it worth telling the user that he/she actually selected a timerange (i.e. the pixel column, accounting for a week of data) instead of a precise point in time? Is it best to just pick one sample and show its timestamp? What if the user selects a region? (i.e. a starting point and an end point on the plot)