| Summary: | Progress Code: completed Statement: The quality of the data are varied as they have originate from multiple sources and have been combined into one database. No implicit quality levels have been set. Only observations where the identification of the animal appears certain have been entered. There are however many observations that are recorded against generic species types such as Shearwater sp. or Prion sp. Position data varies. The observers from the first voyages typically logged positions at ship's local noon. The later voyages, from 1975 onwards, improved the position accuracy by recording positions during each hourly observation. For observations without a directly recorded position, the inferred position has been derived from interpolation from the adjacent recorded positions. Most ships in the open ocean travel in fairly consistent directions, especially in fair weather. The error's from such interpolations is at most likely to be less than 60 km for those interpolations done from 24 hour data gaps and substantially less for voyages where there is an hourly log of positions. The vast majority of the observations have been recorded using local ship time with an unknown correction to UTC. On ANARE voyages, as the ship travels over longitude, local ship clocks are migrated forward or back one hour during night time when it is most convenient for day-based activities. This also coincidentally occurs when there are few observations attempted due to low light or darkness. The only exception is the short period around summer solstice. Assuming the estimate of UTC from the ship clock based on longitude of the observation is at most one hour in error and that ships travel at most 12 knots, then a position error based on this timing issue will be less than 20 km (12 nautical miles). It is most likely that this error is nearer 30 minutes of longitude with an associated spatial error in longitude of less than 10km. Given the size of the surveyed region (longitude 40 east to 170 east, distance at 60 deg south of ...
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