Seis Line – QC services – Importing

Seis Line QC – import

The analyst will follow the defined steps within the workflow when importing positioning data from 2D / 3D land and marine seismic surveys.  The steps they follow will include:

  • Select navigation files(s)
  • Geo-reference navigation data
  • File format checking
  • Data attribute computations

 

Select positioning file(s)

Through the Geo Suite Mapper module the Tool Kit provides an inventory of all recognizes data exchange formats published by IOGP / SEG / Shell, e.g. .

  • UKOOA P1/84, P1/90, P1/11
  • SEG P1/83,
  • SPS (r and s),

After the analyst selects the data sets the import function will automatically determine to which file format the files comply, if any.  A report of the file compliance will be made available.  If the files do not comply to any of the recognized formats then Geo Suite will activate the manual import file wizard to enable the analyst to create a user-defined format for that specific data set.  Either way, the analyst will import all the positioning data into the project database and it stores all the metadata, positioning data and computed attribute data for each of the seismic lines recognized in the dataset.

Data import function

 

Data geo-referencing – selecting coordinate reference system

To the analyst the geo-referencing is an integral part of the import process.  They use the import wizard to assign either a 2D projected or geographical CRS to the data.  The one assigned will be selected because it corresponds to a definition found within the data set header or is contained within an accompanying acquisition or processing report.  The selected option will be taken directly from the EPSG database linked into the Geo Suite Catalague module.

As 3D marine data files contain receiver locations and that the receivers positions are quoted in a 2D projected CRS only it is important that a 2D projected CRS is selected from the geo-referencing panel.

  • late binding datum transformation architecture is used within the product and this is followed by the analyst.  As such the CRS definitions within Geo Suite Catalogue do not have the coordinate transformation parameters assigned as part of the 2D geographical CRS definition.  As such a coordinate transformation model must be assigned to the 2D geographical CRS independently of its definition.  This allows the necessary flexibility demanded of the geomatics profession.
  • All data is stored within the project database referenced to the CRS assigned as part of the import process.   However, the data can be viewed within the Mapper module referenced to a different user selected CRS.  An ‘on-the-fly’ coordinate transformation is performed to convert the data between stored CRS and viewing CRS  (See viewing stage).

File format checker

Files being imported into the project are checked to determine whether they actually comply to one of the data exchange formats recognized within the Geo Suite inventory.

As part of the process a set of reports are generated establishing to which format(s) the import files comply.  Should the import file comply with none of the recognized file formats the function activates the Text Import Wizard that enables the analyst to create a user-defined import format.

 

Data attributes

During the import process a set of data attributes are computed.  These attributes are computed from the positions read from the import files.  These include the determination of streamer feather angles, streamer separations, near trace offsets to name a few.

 

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