Elevation terrains coming from drone surveys may contain man-made objects you don't want to measure. On mining and construction sites, conveyors and other operation structures are common examples of those kinds of objects. Depending on the use case, those items may need to be removed to clean up the digital surface model. For example, it's usually a good workflow for stockpile calculations. Before starting removing items from your elevation terrain, make sure to read this article that explains how to decide to clean the terrain or not.
The Replace Terrain tool allows you to easily clean your data by removing surface objects that are not part of the elevation terrain in a few clicks. You can find the Replace Terrain button in the Tools group of the HOME tab. In this tab you can also find the Remove Object tool that delivers similar results in one click. Nevertheless, this high productivity tool should be used for relatively small and simple objects like machines and vehicles.
|Remove Object||Replace terrain|
|Workflow||1 click||Multiple clicks|
|Main feature||Faster and easier||More robust|
|Applicable plan||Peak||Ridge and Peak|
Quick Usage Guide
- Enable Replace Terrain mode by clicking on the Replace Terrain button in the Home tab.
- Draw a polygon around the area you want to remove within the viewport with left-mouse click.
- Right-mouse click to complete.
- The terrain is flattened (through a terrain modifier).
- When the elevation terrain is fully cleaned up, exit the Replace Terrain mode by clicking on the Replace Terrain button in the Home tab or make a right click.
The Replace Terrain and the Remove Object tools have similar use cases. They both help remove non-expected objects from the elevation terrain. The Remove Object tool is a productivity tool. Nevertheless, similar results could be delivered by the Replace terrain tool, but the user has to spend more time outlining the items to be removed. In addition, the Replace Terrain tool is usually considered as more robust. It could be considered as a remediation tool when the one-click tool can't erase the unexpected object from the elevation data.
- Removing large (excavators, bulldozers...) and small (cars, pick-up trucks...) vehicles and machines.
- Removing conveyors.
- Removing materials (manholes, pipes, shipping containers...).
- Removing machines that stand on a slope or a ditch where the Remove Object tool typically doesn't work.
Tips and Tricks
- When the elevation terrain below the unexpected objects is very complex it makes sense to create a surface (eventually with breaklines) to modify the elevation terrain. Instead of using the Replace Terrain or Remove Object tools, you can create a surface according to your knowledge of the site that includes breaklines, field shots, or other survey items. You can then use the Modify Terrain button available in the Terrain section of the TOOLS tab to create a Terrain Modifier. This workflow may be useful when conveyor arms cross quarry high walls. Have a look to that video to learn how to create surface with breaklines.
- The terrain modification may be deleted and you can come back to your original elevation data by turning off the Terrain Modifier within the project view.