sync
Sync the plotted alert impacted-area overlays to the given desired set, WITHOUT floor scoping (property-level / back-compat). Every supplied area whose rings are usable is plotted regardless of the current visible floor.
Parameters
the map's custom plot surface
the FULL desired set of active-alert impacted-area polygons (empty removes every previously plotted overlay)
Floor-aware sync: keeps the plotted overlays in sync with the desired set, scoped to the current visible floor. The FULL areas set is retained for re-sync on floor change.
An area is kept in the desired (plotted) set when it is property-level (floorId == -1, always visible) OR it is on the current floor (floorId == currentFloorId and its building matches currentBuildingId or is -1). Concrete-floor areas on a different floor are excluded so the stale-removal branch hides them; returning to that floor re-plots them via the plot branch. When currentFloorId == FLOOR_ANY no floor scoping is applied.
Parameters
the map's custom plot surface
the FULL desired set of active-alert impacted-area polygons
the currently selected building (-1 if none)
the currently visible floor (FLOOR_ANY = no scoping)