Seis Line – QC services – Publishing

Seis Line QC – Publishing

The final process performed by QC analyst is to export the edited files to a format required by the client.  The format chosen will reflect the data exchange format required for importing to their corporate data store, with the data being referenced to the required coordinate reference system.  At his disposal the QC analyst will have the following:

  • An inventory of data format encoders to match the data import decoders.
    • This permits data to be exported to any required exchange format regardless of the original import format.
  • Choice of CRS to which the data is referenced.
    • This can be different for the CRS used to import the original data.
      • For example, original data was referenced to local geodetic datum and the export will be referenced to global geodetic datum
  • The analyst will only export a sub-sets of the original data.  This can either:
    • By decimating the data, i.e. only exporting every 20th event.
    • Only exporting lines that successfully passed the QC processes.
  • Exporting the data to a GIS file formats such as .shp, .kml, kmz.

  • As part of the QC process the company endeavors to replicate the metadata for the dataset.  This requires that the fields within the Header Block of the exchange file be populated where possible.  The analyst has panels enables to capture the associated metadata associated so it can be written to the exported file:

  • Where required the analyst will change the CRS to which the exported data is to be referenced.  This will be determined by client requirements who will often wish the store all their positioning data, for a specific geographic area, referenced to the same geodetic datum and projected onto the appropriate map projection.  Consideration must also be given to the format to which geographical coordinates are written, e.g. sexagesimal, decimal degrees, degrees and decimal minutes.

  • Typically, a  sub-set of the lines contained within the project will be exported.  The analyst will use the ‘Select Lines’ panel to determine which sub-set to be chosen.  This will allow only ‘good lines’ to be chosen, or allow only ‘bad lines’, or a user defined selection.

Export to KML file format

  • The analyst will export the seismic line data to both KML file format and .shp file using the GIS export function.   The KML option is selected from the export panel and the data is automatically transformed to WGS84 2D geographical CRS [4326] to be compliant with the published format.  Typically, for land seismic surveys the exported file is superimposed on to google earth to give a general correlation against the terrain features over which the data was acquired.  This is considered to be a secondary visualization check external to the software and is good if the client cannot supply any background imagery from the original data acquisition.

Export to Shp file format

  • The seismic line data is also exported to ESRI .Shp file format using the GIS export function.  The export function will export two .shp files, namely:  Shot points (event points) and seismic line.   The CRS to which the data is exported is a user-defined variable is assigned as part of the export process.  This includes assigning the coordinate transformation model as part of the late binding architecture.

 

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