In ArcMap, by default, all the data points in a LAS dataset are displayed as point clouds if no filter is applied. It is possible to display, classify, and extract data points to only ground points to produce a high-quality elevation model like triangular irregular networks (TIN).
In this example, the data points are classified to only ground points and extracted as a TIN-based surface to represent the ground points as a continuous ground surface consisting of triangular facets.
Follow the steps below to extract LAS ground points from a LAS dataset to a TIN-based surface in ArcMap.
The following steps require the 3D Analyst license. To enable the ArcGIS 3D Analyst extension, in the main menu, click Customize > Extensions. In the Extensions dialog box, check the 3D Analyst check box, and click Close.
- Add the LAS dataset to the map.
Refer to ArcMap: Create LAS Dataset for more information on constructing a LAS dataset.
- Classify the ground points in the LAS dataset.
- In ArcToolbox, navigate to 3D Analyst Tools > Data Management > LAS Dataset > Classify LAS Ground.
- Under Input LAS Dataset, choose the LAS dataset layer.
- Optionally, set the Ground Detection Method and the DEM Resolution parameter. Click OK.
- On the LAS Dataset toolbar, for Filters, select Ground from the drop-down list.
- In Point Symbology Renderers , select Class from the drop-down list to display ground points.
- Display ground points classification in the data frame.
- In the Table of Contents, right-click the LAS dataset, and select Properties.
- On the Filter tab, under Classification Codes, check the 2 Ground check box, and click OK.
Ensure only one classification code is selected. If other codes are selected, the TIN layer includes points other than the ground and takes a longer time to process.
- Click Surface Symbology Renderers and select Elevation. A TIN surface of only points representing ground is displayed.
- Use the LAS Dataset to TIN tool to export the LAS dataset as a TIN layer.
- In ArcToolbox, navigate to 3D Analyst Tools > Conversion > From LAS Dataset > LAS Dataset to TIN.
- Under Input LAS Dataset, select the LAS dataset layer.
- Set a name for the Output TIN.
- Optionally, set the Thinning Type, Thinning Method, Thinning Value and Maximum Number of Output Nodes. Click OK.
The image below shows an example of a classified LAS dataset for ground surface exported as a TIN layer.