Came across this interesting map projecting cherry blossom times in Japan for 2019. Looks like a weather map, doesn't it? Tokyo cherry blossoms forecast to hit peak on March 29 - The Mainichi
Well, "Data by Weather Map Co." If that's what you do, then that's what you do. :) They're just tracking 'Somei-yoshino'. It certainly makes for a nice tidy trip plan. We have two cultivars with large populations here - 'Akebono' (blooming early mid-season) and 'Kanzan' (blooming late season). It would be impossible to do map in the lower mainland like that, and we don't have ornamental cherries of any number over such a vast area as that. Even if we were attempt to do it for Victoria, Vancouver, Kamloops, then continuing north and east, if they had the cherries and we had the data, it would be so hard to pick the date to use for Vancouver.
Sorry, I wasn't trying to suggest a map be created for our area. As you pointed out, ours is but a small area compared to that of the entire country of Japan.