There are no EASYG
formatted data on the R/V FAY CD-ROM A simple data format containing observed gravity, ship's velocity components, and date and Greenwich Mean Time. Data in this format were generally digitized by hand (i.e., entered via keypunch or computer terminal) and may include observed magnetics value. Also, the data format may optionally provide ship's speed and heading rather than the ship's velocity components.
An EASYG data format file would consist of three of the following four record types. Data files will always contain a record-type 1 at the beginning of the file or when there is a change in date or in the observed gravity range value. A record-type 1 is always followed by a record-type 2 and indicates the new date or range value. These records are then followed by one or more record-type 3A or 3B until a new change of date or range occurs. Record-type 3B is an alternate data record format to record-type 3A. Record-type 3B is similar to 3A with the exception that the ship's direction is recorded in terms of speed and heading rather than velocity north and east components.
There are no EASYG
formatted data on the R/V FAY CD-ROM
COLS FIELD NAME FORMAT
---- -------------------------------- ------
1-4 change indicator 9900 I4
COLS FIELD NAME FORMAT
---- -------------------------------- ------
1-2 day I2
3-4 month I2
5-6 year I2
8-10 gravity range (milligals) I3
12-13 magnetics range (gammas) I2
COLS FIELD NAME FORMAT
---- -------------------------------- ------
1-4 time of day (GMT as HHMM) I4
1-2 hour of day I2
3-4 minutes of day I2
6-9 observed gravity (milligals) F4.1
11-16 velocity north (knots) F6.2
18-23 velocity east (knots) F6.2
25-27 observed magnetic value (gammas) I3
COLS FIELD NAME FORMAT
---- -------------------------------- ------
1-4 time of day (GMT as HHMM) I4
1-2 hour of day I2
3-4 minutes of day I2
6-9 observed gravity value (milligals) F4.1
11-16 ship's speed (knots) F6.2
18-23 ship's heading (degrees) F6.2
25-27 observed magnetic value (gammas) I3
RANGE is the medium-order digits of the observed
value and
OBSERVED is the 3 low-order digits combined
to create the observed gravity value.
Example:
980326.4 milligals
9 - implied
803 - range
26.4 - observed gravity
This example does not include the optional magnetics data.
1
1234567890
----------
9900
230976 797
2330 88.8
2335 88.5
2340 87.7
2345 87.7
2350 86.6
2355 85.9
9900
240976 797
0 86.7
5 85.5
10 84.0
15 85.2
20 86.0
