USGS Cruise MGNM 99023 Boomer Survey
Field Navigation Data & Shotpoint Maps
Shotpoint Navigation Data:
|The navigation is stored in ASCII
files using eight fields separated by commas.
- Field 1: Longitude
- Field 2: Latitude
- Field 3: Line Number
- Field 4: Shot Number
- Field 5: UTM Zone 18 Easting
- Field 6: UTM Zone 18 Northing
- Field 7: Year
- Field 8: Julian Day:Hr:Min:Sec
| Hudson Shelf
Nearshore Area | Hudson Shelf
Raw Navigation Data:
The raw navigation was collected using a differential GPS system (Ashtech). These
files represent the raw data recorded on floppy disk aboard ship. The data are
in NEMA format. WARNING: These data have not
been checked for errors. Use with caution.
To aid viewing of the original raw navigation data, each data entry was reformatted
(removing the NEMA codes) by filtering the raw data files through a UNIX awk script..
Every navigation fix from the original data has been preserved however.
The navigation is stored in ASCII files using six fields separated by tabs, with
each file representing a separate julian day (i.e. jd208web.txt). Navigation fixes
are at 10 second intervals. The start and end of each line is marked within each
reformatted navigation file.
- Field 1: date and time (julian day:hour (GMT):minute:second)
- Field 2: Latitude (decimal degrees)
- Field 3: Longitude (decimal degrees)
- Field 4: Speed (in knots, computed from the navigation)
- Field 5: Heading (in degrees, computed from the navigation, i.e.
course made good)
- Field 6: Water Depth (derived from a Furuno digital echo sounder).
Depths are in meters, but have not been corrected for the depth of the transducer,
which was about 1 m below the sea surface
Download Files (click on the Julian Day):
Julian Day: 208
| 209 | 210
| 211 | 212