Change / Delta in timeseries with multiple lines.

[luttik]

I have a line-graph depicting a timeline with multiple lines (i.e. in the data menu I have Date as Group, Fase as line, and sum(size) as "height of line"). What I want to have is a graph with the same metrics but the delta of size (i.e. for every day the amount that size has increased/decreased).

For one line this works with sum(size) - above(sum(size)) but for multiple lines above seems to reference the other line (i.e. Fase) instead of the previous date.

I hope you can help

[luttik · Accepted solution]

I fixed my own problem this is the statement:

aggr(sum(size) - above(sum(size)), fase, date)

For me the issue wat stat the aggregation looks like it should be aggregated by date first and then the fase, but it seems to be the other way around.