Create a light-weight surface over a quarry using the speed of a computer-generated point grid to highlight the breaks in all of the slopes, survey the surface and edit your points, create a TIN and edit the surface where necessary, then export your results as a .dxf, .shp, or .xml file to load into CAD software.

Overview

• Step 1: Import Your Drone Survey Data
• Step 2: Create a Boundary for Survey Items
• Step 3: Densify the Boundary
• Step 4: Create a Q-Points Grid
• Step 5: Remove Points from Objects 
• Step 6: Create the Surface
  • Optional: Optimize the TIN to Better Match the Elevation Terrain
• Step 8: Final Review and Edits to the Surface
• Step 9: Export the Surface
• Tips & Tricks

Step 1: Import Your Drone Survey Data

Start your work by creating a new project in Virtual Surveyor. 

1. Create a project.
2. Drag and drop or load your drone survey dataset (Orthophoto + DSM) into Virtual Surveyor.

Step 2: Create a Boundary for Survey Items

Create a boundary to define the area where you want to create the surface. 

1. Enable the Boundary drawing mode from the HOME tab.
2. Draw a boundary around the area you want to create a surface.

In this example, creating the boundary only took four clicks; we'll densify the boundary to the terrain in the next step.

Step 3: Densify the Boundary

You want to densify the boundary so that your surface will fit nicely with the surrounding terrain, i.e. accurately model the surface to the Elevation Terrain.

1. With the Boundary selected, go to the TOOLS for Boundary tab.
2. Go to the Densify tool in the Transform section of the tools.
3. Set the Method to Break Points.
4. Set the Elasticity to 0.5m (or 2ft).
5. Click Densify to drape the boundary onto the Elevation Terrain.

Step 4: Create a Q-Points Grid

Create survey points within the boundary using the Q-Points feature available in the HOME tab. Q-Points is a feature that generally works best over areas of dirt or where the ground is clearly visible.

1. Select the Boundary.
2. In the Point Grid section of the menu bar, change the Type to Q-Points.
3. Set the Elasticity.
   1. For this example, we've set the Elasticity to 0.5m (or 2ft).
4. Click Point Grid to create the surface points.

The Q-Points function scans the terrain and places points at locations that contribute significantly to the topography. Setting the Elasticity to 0.5 m means the resulting surface never deviates more than half a meter from the original Elevation Terrain. When creating your own surface, use your best judgment as a surveyor to maximize your results when using the Q-Points function. The lower you set your Elasticity value, the more detail you will capture on the elevation terrain. More detail means more triangles, so you need to use your own judgement for what is best to create a surface for the terrain you are working on as to whether you need more detail or not.

Step 5: Remove Points from Objects 

Edit the surface by deleting or moving points and survey items that land on worksite equipment, trees, vegetation, etc. 

• You can use the Area Select tool to select and delete multiple points. 
• You can also use Erase, available in the HOME Tab, to select each point and delete them individually.

In the example below, we are removing points from worksite equipment using Area Select.

After you have removed points from the unwanted objects on the terrain, you are ready to create the surface.

Step 6: Create the Surface

1. Select the Boundary. 
2. In the HOME tab, go to the Toposurface group and click Triangulate Within.
   1. Using Triangulate Within confines the surface to stay within the boundary and thereby is contained in the area of interest for your created surface.
3. The surface is created and shown as a TIN by default.

Optional: Optimize the TIN to Better Match the Elevation Terrain

Virtual Surveyor has a tool called Auto-Flip Edges that gives your surface item additional information by optimizing the triangles to match the underlying terrain. This tool is especially effective on bare-earth terrain like open-pit mines and quarries. Select the surface then click on Auto-Flip Edges found in the TOOLS tab.

The image below is a comparison of a triangulated surface with the edges flipped by the Auto-Flip Edges tool. This tool works to align the triangle edges with the breaks in the slopes. 

Step 8: Final Review and Edits to the Surface

After the Surface is created, you may see additional points or vertices that still need to be removed from machinery or other objects and areas from the terrain. You can quickly remove vertices by highlighting the surface and clicking on Edit Surface found in the TOOLS tab. Then select the Remove Vertex edit mode. You can remove vertices by clicking on each point individually, or by holding shift + left-click and dragging a box around a selected area of points.

Step 9: Export the Surface

To use the surface in a CAD software program, go to the Export Tab and export the surface as a .dxf, .xml, or .shp file. You can read more about exporting a survey or just follow the steps below for a quick export.

1. Go to the EXPORT tab.
2. Under the Survey section, choose your desired Format.
3. Click Export Survey and save the file in the desired folder location.

The Export feature works with the concept of "what you see is what you get" or "WYSIWYG". Whatever surface style and/or survey items are displayed or active in the Viewport are exported along with the surface.

Open the surface in CAD. Load the exported file in CAD to preview your work.

Tips & Tricks

• If you didn't use the boundary to create your surface, you may need to use the Remove Edges tool to remove the outer triangle edges that fall outside of your area of interest.
• If the survey specifications require a line survey, take a look at our article Create a Line Survey for a Quarry for ideas on how to quickly create breaklines.
• You can also display the surface as contour lines; read our article About Surface Styles if you'd like more information.