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:
- Import independently measured check points into Virtual Surveyor.
- Select the Elevation Terrain in the Project View and click on the EXPORT tab.
- 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.
- In the Check Points Statistics window, see if the Average Error shows as a positive or a negative value.
- If it is "0.00", your data is measuring accurately!
- If it shows as either a negative or positive value, you may want to apply an offset to increase the accuracy.
- In the example image below, the Average Error shows as 0.22 ft. and your RMSE is .25 ft.
- Click OK.
- Ensure the Elevation Terrain is still selected and click on the TOOLS tab.
- Set your Offset Z to 0.22 ft and press Enter to move the Elevation Terrain up.
- You will see the terrain update in the Viewport.
- Go back to the EXPORT tab and click Check Points.
- Your Average Error now shows 0.00 ft and your RMSE is more accurate at only .11 ft.