Digital Surface Model (DSM)

A Digital Surface Model (DSM) contains the "the first reflected surface detected by the sensor. These first returns may be reflected by bare ground or by surface features such as trees and structures." (U.S. Geological Survey, n.d.)

Sources

"What is the difference between a DEM and a DSM?". USGS, U.S. Geological Survey. n.d.
https://www.usgs.gov/faqs/what-difference-between-a-dem-and-a-dsm
Accessed February 21, 2019.