| Class | Subject | Notes |
|
| gloc | altitude | Altitude is measured as height above mean sea level (MSL), although
there are various models for MSL. Negative if below MSL. |
| gloc | latitude | Latitude is measured as positive north of the Equator, negative south
of the Equator. Range: -90 to +90. |
| gloc | longitude | Longitude is measured as east longitude; west longitude can be expressed
as negative numbers. Range is either 0 to 360, or -180 to +180. |
| gloc | time | Time of an observation, or applicable time of an integrated measurement
or grab sample. |
| gloc | launch time | Launch time of an aircraft or sounding platform (balloon, rocket,
dropsonde, etc.). |
| gloc | sample start time | Start time of a grab sample or integrated measurement. Requires an
associated stop time. |
| gloc | sample stop time | Stop time of a grab sample or integrated measurement. Requires an
associated start time. |