U.S. Geological Survey Data Series 254
Trackline maps were created with ESRI ArcGIS 9.1 software, exported to Adobe Illustrator for further editing, and saved in JPEG format. These images can be accessed through the links provided below or from within the CRUISENAV folder. The navigation data used to create these maps have not been corrected for the offset between the shotpoint and GPS antenna (see fig. 1). For more information about the GIS project, refer to the Software page.
The trackline maps contain links to interactive profiles, printable profiles, and line navigation maps. The line navigation maps, which have been corrected for the GPS offset, were created with CTI SonarWeb software and are stored in the LINENAV folder. Refer to the Profiles page for more information about the interactive and printable profiles.
NOTE: No navigation was written to the SEG-Y headers for most of line 06c01; therefore, no line navigation map or interactive profile could be created for this line. However, navigation was collected for a coincident sidescan sonar trackline. This sidescan sonar navigation was merged with the Chirp shotpoints by the recorded time to create the reconstructed tracklines found on the location and survey maps. Incidentally, the sidescan sonar line started at shotpoint 1500, so no navigation exists for the first 1499 shots of line 06c01.
Survey Area Map
Shotpoint navigation files and 1,000-shot-interval location files were extracted from the trace headers of each line using Seismic Unix software. These files were then processed with PROJ.4 software (http://www.remotesensing.org/proj) to generate latitude and longitude coordinates from UTM coordinates and reformatted for use with ESRI GIS software. The processed navigation data have not been corrected for the offset between the shotpoint and GPS antenna (see fig. 1).
The processed shotpoint navigation and 1,000-shot-interval location files can be accessed through the links provided below or from within the NAV folder. Each ASCII text file contains eight fields separated by commas and defined as follows:
Field 1: Longitude (decimal degrees)
Field 2: Latitude (decimal degrees)
Field 3: Trackline Number
Field 4: Shotpoint Number
Field 5: UTM X (Zone 17)
Field 6: UTM Y (Zone 17)
Field 7: Year
Field 8: Day of Year:Hour:Minute:Second (UTC)
Processed Shotpoint Navigation
Reconstructed Shotpoint Navigaion
Processed 1000-Shot-Interval Location Navigation
Reconstructed 1000-Shot-Interval Location Navigation
Shotpoint navigation files were extracted from the trace headers of each line using Seismic Unix software. Unprocessed navigation files are stored as ASCII text files in the RAWNAV folder. These navigation data have not been corrected for the offset between the shotpoint and GPS antenna (see fig. 1). Each file contains six fields separated by a space and defined as follows:
Field 1: Trackline Number
Field 2: Shotpoint Number
Field 3: UTM X (Zone 17)
Field 4: UTM Y (Zone 17)
Field 5: Year
Field 6: Day of Year:Hour:Minute:Second (UTC)