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Data formats application and extensions 

SeaDataNet defined ODV ASCII and NetCDF (CF) as standards for harmonised delivery of data sets through the downloading process, while MedATLAS is an optional format.

For Geo-Seas it was required to examine this list both for geological and geophysical data sets and to formulate an extended list of supported data formats.  This has resulted in 2 guidelines that are defining how the SeaDataNet standard file formats should be used for Geo-Seas types of data and what extra data file formats should be supported to handle specific data types.

This manual for data providers describes in detail how to format a range of geological analysis results in a standard ODV ASCII format. It describes the different types of geological data sets that result from analyses carried out on samples and cores. It explains the use of the ODV format and lists the vocabularies and classifications from both the Common Vocabularies and the GeoSciML lexicon which should be used for these data types. It is complimented by a set of example ODV files have been prepared to demonstrate what is required from the data providers.

Practical approach for multiple analyses on a sample / core:
Geological samples/cores taken in the field provide basic metadata for the CDI. Subsequently multiple analyses may be carried out on these samples, for example, grain size analysis, chemical analysis, spectral analysis, etc. In order to describe this in the CDI metadata and to make the resulting analytical data accessible for Geo-Seas users the following approach has been adopted in Geo-Seas:

Each field sample / core is described, including metadata information such as position, date, collector, instrument, platform etc, in a single individual CDI record; in addition all the relevant parameter groups (using P021 vocabulary) for all the analyses that have been carried out on that specific sample are also included in this CDI. However different analyses might have been carried out on different sections of the individual sample/core. This is particularly applicable for core material so that there might be a lithological log analysis which gives a classification of the sediment type for a number of depth intervals. In addition there may be analytical data for a number of subsamples from specific depths in the sample. It was originally planned to combine all these analyses in a single ODV file. However, this has proved to be very complex and difficult to handle, especially because of the various vertical depths down the sample/core. Also understanding these integrated ODV files is potentially very difficult and likely to hamper their subsequent use and representation. In order to prevent the complexity of merging these multiple analyses into one ODV file, a single CDI metadata record has been created which has multiple ODV files associated with it, one for each specific analysis. These files are then packed as a single file (using zip, arj  etc) which is shown as a single packed file in the Download Manager Coupling Table.

This manual for data providers describes in detail the agreed standards for the transport of geophysical data including: ODV data format and standards adopted for geophysical tracks, NetCDF for gridded geophysical datasets and XTF for side-scan sonar. SEG-Y will be used for the seismic and UKOOA P1/90 for the navigation tracks of seismic surveys.

To allow ease of access to the geological and geophysical data sets for end users, Geo-Seas has minimised the number of standard data formats used for data delivery and exchange within the project as far as possible. The majority of the data types selected for the purposes of data delivery within the Geo-Seas project are also used for the SeaDataNet project. This allows the reuse of the existing SeaDataNet technologies and also facilitates interoperability between the various data types. It will also assist in the development of multidisciplinary data products. Geo-Seas partners therefore agreed that Track data (data that are sampled along a trackline) will use the ODV format and Gridded data (data referencing a grid, for example, a DTM) will use the NetCDF format.

However, a number of data types can be delivered in either format. For example, marine geophysical data is generally captured along survey tracks, but after processing this data becomes gridded data which can then be delivered in NetCDF format. A detailed specification for each data format has been drafted. As for all data formats it is essential that sufficient metadata is captured for each data set to ensure that the link can be made to the associated CDI metadata.

The following table gives the agreed overview of the Geo-Seas data types and the proposed data transport formats.

 

 

Data Type

Accepted Formats

 

Geological data (point)

ODV & GeoSciML

 

Geological data (gridded)

NetCDF

 

Grab samples and unconsolidated

ODV & GeoSciML

 

Specimen

ODV & GeoSciML

 

Rock Cores

ODV & GeoSciML

 

Gravimetry (tracking)

ODV

 

Gravimetry (gridded)

NetCDF

 

Magnetic (tracking)

ODV

 

Magnetic (gridded)

NetCDF

 

Bathymetry (tracking)

ODV

Bathymetry (gridded + swath)

NetCDF

Borehole

ODV & GeoSciML

Borehole (images)

PNG

Heat Flow

ODV

Seismics (digital data)

SEG-Y

Seismics (scanned images)

TIFF / PNG

Seismics (navigation)

UKOOA

Side scan sonar

XTF

Images

PNG

Maps (data products)

GeoSciML

       


The NEMO software package can be used for converting any ASCII format to the standard  ODV ASCII data format. The application of geological classifications in ODV for describing lithological logs gave cause for an upgrade of the software, because it was so far only fit for handling numeric values. The upgraded NEMO version is now available.