[Leftcoast]

I find it useful.  The lines coming from the origin show the slope for each doubling frequency and were incredibly useful at the beginning of the infection, less so now. The doubling rate looks to be based on a 7-day average and shows how long it would take to double at that rate. 

It works for me since the chart identifies the highly impacted counties by cumulative cases (LA, San Diego, Riverside) plus the high growth rate counties by color code and slope (Fresno, Humboldt, Kings).

[Leftcoast]

I find it useful.  The lines coming from the origin show the slope for each doubling frequency and were incredibly useful at the beginning of the infection, less so now. The doubling rate looks to be based on a 7-day average and shows how long it would take to double at that rate. 

It works for me since the chart identifies the highly impacted counties by cumulative cases (LA, San Diego, Riverside) plus the high growth rate counties by color code and slope (Fresno, Humboldt, Kings).