Extract the tree canopy height from a lidar dataset in ArcGIS Pro

Summary

The Digital Surface Model (DSM) and the Digital Terrain Model (DTM) are two of the most common lidar-derived data, representing the top of the earth's surface and the elevation of the surface, respectively. In ArcGIS Pro, the height or distance between the ground and the top of the tree canopy can be extracted from the DSM and DTM layers using the Raster Calculator geoprocessing tool. This method is useful in creating a forestry model of the first return defined by the lidar dataset, for example, the Canopy Height Model (CHM). The workflow provided in this article involves creating DSM and DTM layers from a lidar dataset to extract the tree canopy height, as shown in the image below.

Procedure

1. Open the project in ArcGIS Pro.
2. Create the DSM layer from the lidar dataset using the LAS Dataset To Raster tool.
   1. In the Contents pane, right-click the LAS dataset layer, hover over LAS Filters, and click 1st Return.
   2. In the Geoprocessing pane, search for and open LAS Dataset To Raster (Conversion Tools).
   3. In the LAS Dataset To Raster pane, for Input LAS Dataset, select the LAS dataset layer from the drop-down list.
   4. For Output Raster, click Browse and specify a location and name for the output raster.
   5. For Cell Assignment, select Maximum from the drop-down list.
   6. For Sampling Value, specify the value to define the resolution of the output raster.
   7. Click Run.

3. Create the DTM layer from the lidar dataset using the LAS Dataset to Raster tool.
   1. In the Content pane, right-click the LAS dataset layer, hover over LAS Filters, and click Ground.
   2. Repeat Steps 2b through 2g. For Cell Assignment, select Minimum from the drop-down list.

4. Subtract the DTM layer from DSM layer using the Raster Calculator tool to get the tree canopy height.
1. In the Geoprocessing pane, search for and click Raster Calculator (Image Analyst Tools).
2. In the Raster Calculator pane, for Rasters, double-click the DSM layer to add the layer to the expression box.
3. For Tools, double-click the minus (-) operator.
4. In the Rasters parameter, double-click the DTM layer to add the layer to the expression box.
5. For Output raster, click Browse and specify a location and name for the output raster.
6. Click Run.