# dsmtin

From lidR v2.1.0
by Jean-Romain Roussel

##### Digital Surface Model Algorithm

This function is made to be used in grid_canopy. It implements an algorithm for digital surface model computation using a Delaunay triangulation of first returns with a linear interpolation within each triangle.

##### Usage

`dsmtin(max_edge = 0)`

##### Arguments

- max_edge
numeric. Maximum edge length of a triangle in the Delaunay triangulation. If a triangle has an edge length greater than this value it will be removed to trim dummy interpolation on non-convex areas. If

`max_edge = 0`

no trimming is done (see examples).

##### See Also

##### Examples

```
# NOT RUN {
LASfile <- system.file("extdata", "MixedConifer.laz", package="lidR")
las <- readLAS(LASfile)
col <- height.colors(50)
# Basic triangulation and rasterization of first returns
chm <- grid_canopy(las, res = 1, dsmtin())
plot(chm, col = col)
# }
# NOT RUN {
# Potentially complex concave subset of point cloud
x = c(481340, 481340, 481280, 481300, 481280, 481340)
y = c(3812940, 3813000, 3813000, 3812960, 3812940, 3812940)
las2 = lasclipPolygon(las,x,y)
plot(las2)
# Since the TIN interpolation is done within the convex hull of the point cloud
# dummy pixels are interpolated that are strictly correct according to the interpolation method
# used, but meaningless in our CHM
chm <- grid_canopy(las2, res = 0.5, dsmtin())
plot(chm, col = col)
# Use 'max_edge' to trim dummy triangles
chm = grid_canopy(las2, res = 0.5, dsmtin(max_edge = 3))
plot(chm, col = col)
# }
```

*Documentation reproduced from package lidR, version 2.1.0, License: GPL-3*

### Community examples

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