Do things by layer, instead of by column

[adrfantini]

It might be possible to check for events by doing things layer by layer sequentially, using a raster for the current value, one for the previous value, one for the year of the start of the event and one for the number of events. Or something along those lines. This might be faster, who knows, but would also have the advantage that you could actually read layer by layer (which is how most of these files are chunked). Maybe as an option?

Currently we read everything in a single shot and perform computation in parallel separately for each cell.