Table schema:
CREATE TABLE table_name_68 (elevation_groundstation INTEGER, slope_length VARCHAR, capacity_in_persons_hour VARCHAR, name_or_route VARCHAR)

Question: Which elevation groundstation has a capacity in persons/hour larger than 820, and a Name or route of lager 1, and a slope length smaller than 336?
SQL: SELECT AVG(elevation_groundstation) FROM table_name_68 WHERE capacity_in_persons_hour > 820 AND name_or_route = "lager 1" AND slope_length < 336