Learn how to perform vertical clearance measurements with the Trimble® Business Center using Mobile Mapping dataset in the context of a best practice workflow. This is a manual procedure where one point has to be picked from the point cloud. The software will then compute the vertical clearance with respect to the ground.
The following steps will guide you through an example using Trimble® MX9 system data.
The application scenario is the calculation of vertical clearance for objects above the road surface. In this example, we assume that data was collected on a multi lane highway and vertical clearance measurements were taken for each overhead road sign, as displayed in the following image. The center of each lane marking is the reference for the clearance measurement.
Tools and procedure
The first step is to focus on the point cloud region of interest making use of the Limit Box function:
Use the Cutting Plane View tool to create a vertical plane passing in the center of the first marking line.
Pick two points to define the vertical plane, and a third point to position the plane in the center of the lane marking.
In the Plane Manager window:
- Click on New, give a name to the new plane (we gave the name Vertical_Clearance here),
- Select the option Vertical Plane and then pick the points Point 1 and Point 2 to align the plane.
- Pick a last point in the center of the lane, marking to position the plane in the center of the lane marking:
Once done, the Cutting Plane View will open. You can now customize the thickness of the cutting plane:
- Zoom on the point cloud in the Cutting Plane View, and focus on the lowest point of the point cloud.
- Click on the tool Measure Vertical Clearance.
- Set the Clearance down option from the Measurement direction menu and pick the point with the lowest elevation from the Cutting Plane View.
The vertical clearance measurement is now completed and can be saved in a specific layer, by clicking on Save.
Now, move on the second lane marking for the second clearance measurement.
- Open the Plane Manager tool again, as it was just closed after the creation of the vertical plane.
- With the Vertical Plane selected from the Plane List, click on Position, pick a point in the center of the second lane marking.
You can now calculate your second clearance measurement. Once finished with all measurements, you can display the values by turning on the Layer where the measurements were stored. The project is complete.
All vertical measurements can be viewed and exported with a .CSV file report. Select the measurements you want to export form the Project Explorer, right click on measurements in the Stored Measurements container, and Select Measure Distance CSV Report as shown here:
An ASCII file report will be generated with all the clearance measurements details:
By following the above steps, you can now perform vertical clearance measurements with Trimble Business Center software.
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