Background
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Standard definitions of data levels are necessary to inform how data has been processed and to ensure consistently and limit ambiguity when discussing, delivering or describing data. The following definitions are modelled on those defined by NASA for Earth Observations data products.
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L3 v.1
L4 – Verified Final Survey Data
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Data Level
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Notes
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L0
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L0 – Raw Data
L0 data is native format, as recorded by the sensor. It should include all necessary datagrams required for a comprehensive bathymetry and backscatter processing, including raw backscatter per beam (BA) and raw backscatter in time series (TS), and all required ancillary data. Water column data if collected should be stored in a separate file.
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L1
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L1 – Georeferenced Point Data - uncleaned
L1 Data is raw data processed to form a georeferenced bathymetric point cloud with no cleaning
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L2
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L2 – Georeferenced Point Data – Fully Cleaned
L2 data will be cleaned relative to the CUBE Surface.
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L3 v.0
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L3 Gridded Final Survey Product data
L3 is the delivered Final Survey Data for a survey. L3 will be a CSAR CUBE / SDTP surface, which will include density and uncertainty.
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Data Versions
Versioning of bathymetry data is classified as V0 and V1 and directly refers to the vertical datum that the data is published as, as well as the state of the data.
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V0 (Version 0) bathymetry data is published at geodetic vertical datums (e.g. Mean Sea Level (MSL)) and is mainly refers to data that has been manually cleaned, and distributed for release.
Rough Notes
At the time of writing there is a considerable “backlog” of data that has been cleaned for delivery in response to a client request but has either:
Been distributed through GA’s public facing tools as a bespoke deliverable (either for an individual survey, or as part of a compilation), or
Has never been distributed at all.
In both of these instances, the data represents a product of value, albeit limited in that the processing that has been undertaken to date has not been explicitly captured. It is with this data in mind that the GA-ASB data hub is defining a “version 0” for this backlog data.
Important to note – “version 0” is not relevant to any new, incoming data, or data that has never been cleaned or is only partially cleaned previously. Version 0 represents a “quick win” and will be replaced at a later date.
Version 1
V1 (Version 1) is classified as bathymetry data that may have been manually cleaned, surface cleaned, and exported to two vertical datums, Ellipsoid and MSL. This version will be used for all new surveys.
Rough Notes
Version 1 represents the first, truly consistent processing outcome for the GA ASB Data Hub data. Any data within the existing backlog that has not been produced as a V0 will be produced as a V1, via a prioritised publication schedule that takes into account both backlog and new incoming data.
Version 1 will be:
Created using an automated, reproducible processing pipeline