Graphs show data of of "unfinished periods" and "complete periods" in same way.*
Since imho comparison of data of "unfinished periods" with "complete periods" does not make big sense, there should be visiualization for the difference to trigger people to be aware of this problem
One idea is not connecting the data point of "unfinished period" to the others before even this period is finished.
This may look like this:
*why are there unfinished periods?
When comparing data e.g. number of visits, entry pages etc
with data of day before there is a problem:
when checking earlier than 23:59
there is always a difference because
the period taken into account is shorter
than the complete day before
and with this not all "things" of this day has already happened.
An example:
Looking at data at 9:00 in the morning:
actual data is taken from 0:00 to 9:00 = 9h
the data for comparison form 0:00 to 0:00 = 24h
This issue is an extract of
"comparison of data of "unfinished periods" with "complete periods" does not make big sense e.g. in widget" https://github.com/piwik/piwik/issues/10282
which addresses problem in general for data shown in table and in graphs
one other idea was to connect the data point of unfinished period with a dashed/interrupted line
but this approach would be much more "costly" to make it good looking and compatible at all places where graphs are used/shown...
so no connection at all should be fine :-)
another example:
a possible second step:
maybe one can show even an estimated forecast, e.g. like this?
@mattab would be nice to tackle this one at some point as it's always "irritating" for unfinished periods. Maybe there is a way to show the last dot and last line in a light red or something. On hover it could say the day is not yet finished but not sure how complicated it is to implement. Would be useful especially since we want to show more of such graphs.
This would be great, also at the top dashboard where the data of the unfinished day is compared to the completed day.
Added Major
tag and moved into 3.0.0
milestone so we keep an eye on this important issue :+1:
Before working on this need to clarify with @mattab how to solve this problem. Related also https://github.com/matomo-org/matomo/issues/6784 which may need similar solution.
In an ideal world, we would maybe show the forecast line, but this could make the whole issue a lot more complex and time consuming.
So instead maybe we could first start by putting the last section of the line graph into a dash line, indicating to the user that there is something special about this last data point? That might be good enough to remove the "shock" of seeing the data point way down.
That might actually now be easy as our chart libs don't support different looks for the same chart line. Not sure if adding a separat chart line for the last point only would work easily though.
created https://github.com/matomo-org/matomo/issues/18169 . I wouldn't have created one and just waited until someone creates it as we likely won't work on it anytime soon anyway.