Talking about visual trend compression, I’m working with long-term time-series (like days of 1000Hz signals), and there are similar techniques, like you’re interested not only about data itself, but in some processing results, and for different time scales you have different processed “layers” of data. And to observe that data, you should have several plots with different time-scales, linked to each other as a slider, see for example: Interactive plot, acting as a range slider tool for another plot? - #6 by sairus7
For the most frequent (big) data you can plot small time window, that is loaded interactively when you navigate to another time, so you don’t have to store the whole data in memory.
And for sparse (compressed) data you have big time window, so you can see a whole picture and have a detailed look for any small time window, if needed.