If you find that your Elevation Terrain isn't matching your own independently measured check points, you can utilize the information from the Check Points tool (Average Error & RMSE) to shift your data on the Z axis to improve your absolute accuracy. 

Steps to Adjust the Elevation Terrain

Use the Check Points function to see the before and after results of using Offset Z:

  1. Import independently measured check points into Virtual Surveyor.
  2. Select the Elevation Terrain in the Project View and click on the EXPORT tab.
  3. In the Survey section, click Check Points.

    Important! The Check Points tool uses active points to measure for accuracy; be sure to turn off any points that you don't want to include in the measurement.

  4. In the Check Points Statistics window, see if the Average Error shows as a positive or a negative value.
    1. If it is "0.00", your data is measuring accurately!
  5. If it shows as either a negative or positive value, you may want to apply an offset to increase the accuracy.
  6. In the example image below, the Average Error shows as 0.22 ft. and your RMSE is .25 ft.

  7. Click OK.
  8. Ensure the Elevation Terrain is still selected and click on the TOOLS tab.
  9. Set your Offset Z to 0.22 ft and press Enter to move the Elevation Terrain up.
    1. You will see the terrain update in the Viewport.
  10. Go back to the EXPORT tab and click Check Points.
  11. Your Average Error now shows 0.00 ft and your RMSE is more accurate at only .11 ft.