Surveys

 

A survey in GSadjust includes all of the loops (and their respective occupations and samples) that are combined in a single network adjustment. The survey represents a single snapshot in time, although in practice, data may be collected over a period of days to weeks if the gravity field is changing slowly.

 

Surveys can be renamed using the F2 key. The survey name must be in the form of a date (YYYY-MM-DD), but need not be the same date as the data within the survey. Survey names don't need to be unique in order to carry out network adjustment, but they do if computing gravity change. The survey date is used when calculating gravity change trends.

 

If results for more than one survey exist, the difference can be calculated using Compute gravity change. This can be used to calculate change over time, or to compare processing styles. For example, The same dataset could be imported twice (first, using Load raw..., then using Append survey to campaign...), and different drift-correction styles assigned to the respective loop in each survey. Compute gravity change would then show the difference.