Survey Data Processing

In most cases, raw survey data is imported or synchronised to the NEXUS IC database together with the event records. You can also import survey data manually. All survey data must be assigned to a survey set. For more information, see Configure Survey Sets.

You can check survey data associated with specific events on the Event Details pane of the INSPECTION screen (see Event Details).

Matching Survey Sets to Events

Events get their survey data from a particular survey set based on the event’s date and time. That date and time is looked up in the survey data, and the corresponding survey values (Easting, Northing, depth, etc.) for that date and time are displayed. The threshold for survey matching is +3/-2 seconds: if there is survey data up to 2 seconds before, or up to 3 seconds after the event’s date and time, NEXUS will match that event to the closest survey data point. Thus, if you are importing survey data into NEXUS from an external file (for example, a track reposition file supplied by a surveyor), you must ensure that the file has data at least once every 4 seconds. This ensures that there will definitely be a suitable data point to match to any event. It’s accepted to have gaps in a survey set import, provided there are no events you care about in the time span covered by the gap.

Note

In a single survey set, a single point in time can only have one set of survey values associated with it. If you need two events at the exact same time with different survey values, ensure that they are in different survey sets.

Track Repositioning

In case you use the services of a survey company that performs the post-processing of survey data, you need to update the survey data in the NEXUS IC database by importing the smoothed survey data that they provided. This is called track repositioning.

When performing track repositioning, you create a new survey set for the smoothed survey data and reassign that survey set to the relevant events. Track repositioning requires a CSV or MS Excel file of the processed survey data, most likely in the format originally provided in the survey string.

Note

Once you’ve performed track repositioning, consider re-running the anomaly triggers (see Run Anomaly Triggers).

To perform the update of survey data in NEXUS IC based on the smoothed survey data, follow the steps below:

  1. Create a new survey set for the smoothed data. You can create a new survey set in the following ways:

    • In the main menu, go to Configuration ‣ Events ‣ Survey Sets and in the Configuration - Survey Sets dialog, click Add to create a new survey set (see Configure Survey Sets)

    • On the INSPECTION screen:

      1. Select the relevant events on the Event Details tab.

      2. On the Event Details pane, go the Survey tab.

      3. In the Survey Set field, click ellipsis.

      4. In the Select Survey Set dialog, click Add and specify the name of the survey set.

  2. Import the smoothed survey data into the new survey set. To do that, in the Configuration - Survey Sets or Select Survey Set dialog (see step above), select the new survey set and click Import. Follow the steps in the import wizard (see Import Events).

  3. On the Event Details tab of the INSPECTION screen, select the events that you want to reposition. You can filter events in the dialog (for example, by workpack) as required.

  4. On the Event Details pane, go the Survey tab.

  5. In the Survey Set field, click ellipsis.

  6. In the Select Survey Set dialog, select the new survey set.

    Result

    The survey data gets updated for all the selected events.

See also

Configure Survey Sets