Processing collected data

If a project has been configured with the option for manual, desktop post-processing, and post-processable “sessions” have been collected into the project, the workflow for performing and analyzing the corrected data is the same across project types.

All session processing is typically done using the same workflow. Sessions have a status property indicating what step of the workflow they are at.

  1. Sessions are downloaded or checked-in to Terra Office. [Waiting for Correction].

  2. Sessions are post-processed using a post-processing profile. [Corrected Successfully].

  3. Individual features within the session, and / or positions within each feature, are inspected for quality if necessary. (Sessions → Features → Positions)

  4. Updates are made to geodatabase feature geometries (and GNSS metadata attributes) from the post-processed sessions [Updated]

Prior to manually post-processing collected data in the add-in, you must have configured one or more Post-processing profiles.

To review collected sessions:

  1. When in Session Manager mode, the Field Data dockable window will list the collected Sessions for the current project. The list will show the name of the User who collected the data (or the Device that collected the data), the Start Time and End Time of the session (local time zone), some Notes about the session (typically when it was downloaded or stored; mouse-over the session to see the full text in a tooltip), and the current Status. Click the column headings to sort the session list by that column (ascending or descending).

  2. By default, session extents (the extents of the session measurements) will be drawn in a graphics layer on top of the map. They are color-coded based on session status (and if they are selected in the list). If a session is very small, it may be represented only by an “X”. Use the Display session outlines checkbox to hide or show the session extents. If you turn this off, it will also prevent the automatic zoom-to-all-session-extents behavior.

  3. To view session troubleshooting information (satellite and signal-to-noise ratio), right-click a session and select the Show troubleshooting info item from the context menu. In the Show Raw GNSS Data window that opens, review the Satellite Count graph (red lines, scale on left vertical axis) and the Average SNR graph (blue lines, scale on right vertical axis). The vertical bars represent when the user averaged positions for features collected in the session.The horizontal axis is time.

  4. To view session properties (or update the session notes), right-click a session and select the Properties item from the context menu. In the Session Properties window that opens, review the basic session properties. If you want to update the session notes, edit the Session note text area and click Update note.

  5. To zoom to a selected session, select it in the list and click Zoom To . Or, right-click it and select the Zoom to item from the context menu.

To perform post-processing on the collected data:

  1. Select the sessions for post-processing and click Correct… .

  2. In the Correct Sessions window that opens, note the list of Sessions to Correct. If you need to remove a session from the list and not process it, click it and then click Remove.

  3. Select the Processing Profile to Use (they are sorted by distance from the selected sessions) and click Correct to begin the process. If the Delete previous downloads checkbox is selected, Terra Office will always re-download new ones instead of re-using files (for the same profile and time period) that were previously downloaded.

    There will be a line of text that displays under the Processing Profile to Use dropdown. This indicates the base station reference position handling as determined by the Project geodetics and the Post-processing profiles and base stations settings.

  4. During post-processing, status and progress messages are displayed in the large text area to the right in the window. Look for the Finished differential correction message indicating that processing is complete. If you want to save the processing report to a text file, click the Save to file… text link and choose a path and file name.

  5. Click X in the upper right corner to close the Correct Sessions window and return to the Field Data dockable window. Note the updated Status of the session(s).

To inspect the feature data within a corrected (or uncorrected) session:

  1. Select the desired session in the Field Data dockable window and click View Features.

  2. The Field Data dockable window changes to list the features in the selected session. The list includes a Label (layer name and OBJECTID from the geodatabase), Status, Estimated Horizontal Accuracy, and Antenna Type. Click the column headings to sort the session list by that column (ascending or descending).

  3. Each feature in the session will be drawn in a graphics layer on top of the map. They are color-coded based on feature status (and if they are selected in the list). Use the Display estimated accuracy outlines checkbox to hide or show a scaled buffer shape around each feature in the session.

  4. Click one or more features in the list to highlight the selected feature, the accuracy outline (if turned on), and to select the geodatabase feature (typically in ArcMap’s default cyan color). As the results of post-processing have not yet been stored to the geodatabase, this will illustrate the difference in geometries between the post-processed result and the original feature.

  5. If a feature in the session does not meet the accuracy threshold specified for the layer, it will be indicated in the Status column. This will prevent geodatabase features from being updated based on the session. Either re-process the session to achieve better accuracy, or use the Exception button to indicate that you accept that a particular feature does not meet the accuracy requirement.

  6. To disconnect, or unlink, a session feature from the geodatabase feature (e.g., to no longer include it in updates made to the session), select it in the list and click Unlink . The button label changes to Link so that you can re-link them if desired.

    This is not a common part of the workflow.

  7. To zoom to a specific feature or features, select them in the list and click Zoom To.

  8. If you made changes to the features in the session (i.e., you used either the Link / Unlink button, the Exception button, or you performed additional updates to positions within a feature (see next set of steps below), click Apply to update the session.

  9. Click Finish to return to the list of sessions in the Field Data dockable window. You will be prompted to apply your changes if any were made (see step 8 above).

To inspect the position data within a corrected (or uncorrected) feature:

  1. Select the desired feature in the feature list of the Field Data dockable window (this presumes you have already clicked View Features from the list of sessions) and click View Positions button.

  2. The Field Data dockable window changes to list the positions in the selected feature. The list includes the Part (of the geometry construction), Local Time (of the GNSS observation), Status, and Estimated Horizontal Accuracy. Click the column headings to sort the session list by that column (ascending or descending). To view additional columns of position properties, use the Show Extended Data checkbox.

  3. Each position in the feature will be drawn in a graphics layer on top of the map. They are color-coded based on position status (and if they are selected in the list). Use the Display estimated accuracy outlines checkbox to hide or show a scaled buffer shape around each position in the feature.

  4. For viewing the positions in parts hierarchically (e.g., in a line or polygon with complex constructions such as averaged vertex, averaged vertex, path, averaged vertex, path), use the Tree View radio button to toggle the list.

  5. Click one or more features in the list to highlight the selected feature and the accuracy outline (if turned on). As the results of post-processing have not yet been stored to the geodatabase, this will illustrate the difference in geometries between the post-processed result and the original feature. It can also be used to show outlying positions within a feature that affect the overall geometry and accuracy.

  6. To remove a particular position from the feature geometry, uncheck the checkbox at the beginning of its row in the list. To re-select all of the positions for the feature, click Use All.

  7. To edit a left/right offset construction (from the TerraSync workflow), click its entry in the Tree View and click Edit… . Currently, that is the only type of advanced construction that is editable in the office.

  8. Click Finish to return to the list of features in the Field Data dockable window. You will be prompted to apply your changes if any were made.

To push all updated feature geometries and metadata (e.g., accuracies) into the geodatabase after processing and quality checks:

  1. From the session list in the Field Data dockable window, select one or more sessions and click Update Features. This will affect feature geometries and any metadata fields that were configured in the project.

  2. If the project is a TerraFlex Cloud project, you are also prompted to update the features in the cloud.

Some additional, less commonly used functionality is also available from the session list in the Field Data dockable window:

  • To delete a session after processing (but not the features created or updated from it), select it in the list and click Remove.

    This is an irreversible action and should only be done when you are sure you no longer need the session for (re-)processing.

  • To reverse the post-processing of a session and restore the geometries and metadata as originally collected in the field (i.e., what it was at the time of check-in or download), right-click the desired session and choose the Restore to original item from the context menu. If you want to propagate that into the geodatabase features, select the session and click Update Features.

  • To rebuild the feature geometries in a session using the best results from post-processing or real-time corrections, right-click the desired session and choose the Rebuild with best results item from the context menu. This can be useful if the post-processing profile is set to always use the last results regardless of accuracy and you do not want to re-process the session(s) to see how the results would change. If you want to propagate that into the geodatabase features, select the session and click Update Features.

  • To rebuild the feature geometries in a session using the last results from post-processing, right-click the desired session and choose the Rebuild with last results item from the context menu. This can be useful if the post-processing profile is set to always use the best results (may not be the last results) and you do not want to re-process the session(s) to see how the results would change. If you want to propagate that into the geodatabase features, select the session and click Update Features.