Uncover

The partyPartyThe party can include both adventurer and companion units. must fully explore the battle map by gaining all required skyshardsSkyshardA delve is fully explored when all of its skyshards have been revealed and gained. Unless the encounter specifies otherwise, 3 skyshards are required.—by default 3—and then successfully retreat. If the party retreats before fully exploring the battle map, the encounter is failed. Unlike other objectives, the party gains XPXP (Experience Points)The party's total gained XP is tracked by the XP dial. An adventurer's unspent saved XP is tracked on the Saved XP track on the adventurer mat. from each skyshard it acquires in the delveDelveDelve battles represent adventurers navigating an uncharted, labyrinthine space.—up to that delve's required limit— so long as the entire party is not defeatedDefeatedA unit is defeated when it loses its last HP chip or an effect states that it is defeated, in which case no XP is gained. This is true even if the party retreats before it has gained all required skyshards (see Retreating from Battle).

Uncover vs Survey

Aspect	Uncover	Survey
XP Rewards	1 XP for each collected skyshard and encounter reward (if successful). You still gain XP for skyshards if you retreat with at least 1 party member still alive.	Encounter Reward XP only
Partial Completion	You gain XP for each skyshard even if retreating before completing the encounter.	Not possible, encounter is failed.
Encounter Duration	End of battle round, however it is optional even after objective is met.	End of battle round, not optional.