Seismic Reflection, EdgeTech SB-512i chirp tracklines, USGS field activity 2017-003-FA, Mississippi River Delta front offshore of southeastern Louisiana (Esri polyline shapefile, GCS WGS 84)

Scripts within SIOSEIS (version 2015.3.1) and Seismic Unix (version 4.2) were used to process SEG-Y data, create navigation files, and plot images. The processing flow and scripts used to produce navigation files including trackline shapefiles are summarized below and in the following processing steps.
1) SIOSEIS (version 2015.3.1) was used to read SEG-Y files, renumber shots starting from one, extract the envelope-detected trace, and write out new SEG-Y files. The original shot numbers, which were assigned by SonarWiz sequentially over the duration of an acquisition session despite SEG-Y file changes, are preserved in the raw SEG-Y data.
2) The SIOSEIS script Sio_medianstk was used to minimize cross talk from the multichannel seismic acquisition sources (boomer and sparker) with a two-trace median stack (trim 50 percent of the values furthest from the median amplitude) and improve water bottom picking. This script was used for all lines even when multi-channel acquisition was not simultaneously occurring, due to the improvements made to water bottom picks.
3) The script Read512i_mstk was used to read median filtered stacked and renumbered SEG-Y files, write a Seismic Unix file, and extract SEG-Y trace header information, including shot number, longitude, latitude, year, Julian day, and time of day (UTC). Header information from each SEG-Y file was saved to text files after an AWK (no version) filter was used to maintain the first and last shots, shots at multiples of 100, 500, and shots with unique navigation coordinates. Geographic coordinates (WGS 84) were converted to UTM zone 16 N coordinates (WGS 84) using Proj (version 4.6.0). End shots and shots at multiples of 100 may not have unique navigation coordinates. Separate text files containing the first and last shots and even 500 shot intervals were also saved. A 500 shot interval was chosen because it corresponds to the annotation interval provided along the top of the seismic-reflection profile images. Read512i_mstk called a Python script 512itoSQL17003.py, written by Wayne Baldwin, which imported the CSV files to a Spatialite (version 4.3.0) enabled SQLite (version 3.21.0) database, creating two tables containing point geometries for the unique and 500 shot interval navigation. The script also created line geometries from the unique navigation (sorted by LineName and Shot) and wrote them to an additional database table. The tracklines are based on all the shot navigation.
These process steps and all subsequent process steps were conducted by the same person - Wayne Baldwin.

The 512i trackline features were added (Add Data) into ArcMap (version 10.3.1) from the SQLite database, then exported (Right click on database feature class > Data > Export Data) to the new Esri polyline shapefile 2017-003-FA_512i_Tracklines.shp

XTools Pro (version 12.0) for ArcGIS desktop (version 10.3) was used (TABLE OPERATIONS - TABLE RESTRUCTURE) to rename the table attribute heading 'Shot_init' to 'Shot_ini' in the polyline shapefile's attribute table. All other attribute headings were left unchanged.

Added keywords section with USGS persistent identifier as theme keyword.