NAVIGATION DATA - ARCHIVE OF CHIRP SEISMIC REFLECTION DATA COLLECTED DURING USGS CRUISES 01SCC01 AND 01SCC02, TIMBALIER BAY AND OFFSHORE E. TIMBALIER ISLAND, LOUISIANA, JUNE 30 - JULY 9 AND AUGUST 1

SEISMIC TRACKLINE MAPS

The edited shotpoint navigation files and 1,000-shot interval files were used to generate trackline maps with ESRI GIS software ArcView 3.2. The maps were then exported to Adobe Illustrator for final editing and conversion to JPEG images. These JPEG images can be found in the MAPS folder located at the top level of each disc. The ESRI ArcView project and shapefiles used to create the maps can be found in the ARC subfolder of the SOFTWARE folder located at the top level of each disc. The project is compatible with ESRI ArcView and ArcGIS software. The shapefiles can also be viewed using public domain software ArcExplorer 2.0 (Windows) and 4.0 (Windows, Unix, Linux), which can currently be downloaded from the ESRI website at http://www.esri.com/software/arcexplorer/index.html.

Click on the links below to see the trackline maps and access the seismic image files.

FULL SURVEY AREA MAP

EDITED SHOTPOINT NAVIGATION

Navigation files were extracted from the SEG-Y seismic trace headers using Seismic Unix software. They were edited to remove spurious data values and processed using PROJ.4 (Unix/Linux shareware currently located at http://www.remotesensing.org/proj) to convert Zone 15 Universal Transverse Mercator (UTM) coordinates to latitude and longitude.

The edited navigation files can be accessed through the links provided below or from within the EDITNAV subfolder of the NAV folder located at the top level of each disc. Also included are edited 1,000-shot interval files that can be accessed through the links provided below or from within the SHOTNAV subfolder of the NAV folder. These files are all stored by Cruise ID in flat ASCII text file format with a .txt extension. The shotpoint navigation files and 1,000-shot interval files both contain eight fields separated by commas. Each of these fields is defined as follows:

Field 1: Longitude (decimal degrees)

Field 2: Latitude (decimal degrees)

Field 3: Trackline Number

Field 4: Shotpoint Number

Field 5: UTM Zone 15 X
Field 6: UTM Zone 15 Y
Field 7: Year
Field 8: Julian Day:Hour:Minute:Second (GMT)

EDITED SHOTPOINT NAVIGATION:
01SCC01 (all lines)
01SCC02 (all lines)

1,000-SHOT INTERVAL NAVIGATION:
01SCC01 (all lines)
01SCC02 (all lines)

NOTE: The navigation data have not been corrected to reflect the 10-m offset between the shotpoint and the GPS antenna.

RAW SHOTPOINT NAVIGATION

Raw navigation data can be found in the RAWNAV subfolder of the NAV folder located at the top level of each disc. The data are stored by trackline number in flat ASCII text file format with a .txt extension. Each file contains six fields separated by a space. Each of these fields is defined as follows:

Field 1: Trackline Number
Field 2: Shotpoint Number
Field 3: UTM Zone 15 X
Field 4: UTM Zone 15 Y
Field 5: Year
Field 6: Julian Day:Hour:Minute:Second (GMT)

WARNING: These data have not been edited.

NOTE: The navigation data have not been corrected to reflect the 10-m offset between the shotpoint and the GPS antenna.