Matthias Kuhn f80a33be65 [FEATURE] Expose @parent variable in aggregate functions
This makes it possible to access attributes and geometry from the parent
feature when in the filter of the "aggregate" expression function.

With this in place aggregates can be calculated per feature.

E.g. max "measurement" for each point_station per polygon_research_area.

Or a default attribute value when digitizing features:

    aggregate(layer:='countries', aggregate:='max', expression:=\"code\",
filter:=intersects( $geometry, geometry(@parent) ) )
2016-10-27 23:11:50 +02:00
..
2016-09-21 23:30:04 +02:00
2016-10-01 17:58:12 +02:00
2016-09-21 09:12:54 +10:00
2016-05-14 00:21:50 +02:00
2016-09-21 23:30:04 +02:00
2016-09-21 23:30:04 +02:00
2016-09-21 09:12:54 +10:00
2016-04-29 14:10:26 +02:00