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Table of Contents:

OF 2004-1014

Disc Contents

Geologic
    Discussion

Data/GIS

• Getting Started

• Navigation

• Seismic-reflection

• Sidescan-sonar mosaics

• Ground-Truthing

Metadata/Data Catalog

References Cited

Contacts

NAVIGATION

Navigation is available in two formats: ASCII field navigation and Environmental Systems Research Institute (ESRI) formatted shapefiles. All of these files are contained in the data/nav directory. The ASCII field navigation is available for the 2000 survey only. The ESRI shapefiles presented here are for the geophysical survey of 2000. For navigation related to bottom photographs and samples, go to the ground-truthing section.

Field Navigation:

These files represent the raw navigation files that were collected during the 2000 survey using the Precise Positioning Service (PLGR) GPS navigation system. The first set of navigation files was recorded using Coastal Oceanographics Hypack software. WARNING: These files have not been checked for errors. In particular be aware of zero depths from the fathometer when that system was not in operation. Use with caution. The second set was recorded using BlueMarble's Geographic Tracker software. For these data, no fathometer information was recorded with the navigation. Again, these files have not been checked for errors, so use with caution.

SET 1:
The navigation is stored in ASCII files using four fields separated by tabs, with each file representing a separate julian day (i.e. jd259.txt). Navigation fixes are at approximately 10 second intervals.

Field 1: Date and time (GMT): julian day(xxx):hour(xx):minute(xx): second(xx)
(note that time fields are colon delimited)
Field 2: Longitude (decimal degrees)
Field 3: Latitude (decimal degrees)
Field 4: Depth from fathometer (in meters - add 1 to 1.5 meters to account for draft)

Julian Day: 259 | 260 | 261 | 262 | 263 | 264 | 265 | 267

SET 2:
The navigation is stored in ASCII files using four fields separated by tabs, with each file representing a separate julian day (i.e. jd259.txt). Navigation fixes are at approximately 2 second intervals.

Field 1: Date and time (GMT): julian day(xxx):hour(xx):minute(xx): second(xx)
(note that time fields are colon delimited)
Field 2: Longitude (decimal degrees)
Field 3: Latitude (decimal degrees)

Julian Day: 269 | 270 | 271

ESRI Shapefiles:

The data/nav directory also contains trackline and shotpoint navigation shapefiles. The trackline shapefile is a polyline indicating where seismic-reflection and sidescan-sonar data were acquired during the survey. The data are in geographic coordinates, NAD83. The shotpoint navigation enables the seismic-reflection profiles to be spatially correlated based on shotpoint fixes. These shapefiles are 100 shotpoint intervals or 500 shotpoint intervals. In each case, the first and last navigated shotpoint is retained. All of these shapefiles can either be read directly from the DVD, or by transferring the "zipped" files to a preferred location and uncompressing them.

These shapefiles are intended to be opened and viewed with the ESRI ArcView or ArcGIS software. For those individuals who do not have the ESRI software or a compatible GIS data browser on their computer, a free viewer, ArcExplorer, is available from ESRI (http://www.esri.com/software/arcexplorer/). Please note that the ArcExplorer software is limited to the Microsoft Windows operating systems and some UNIX operating systems.

These compressed files were created using the Windows program WINZIP v8.0. For those users who do not have software capable of uncompressing the files, software may be obtained from http://www.winzip.com or http://www.pkzip.com.

Download ZIP Files: Chirp tracklines; Chirp 100 & 500 shotpoint nav