This function allows the user to visualize the working operation of the local maxima finder tree detection algorithm by creating a beautiful GIF of the process.
The function works by taking an input CHM, performing local maxima tree detection with lidR locate_trees, and subsequently plotting the moving window as it proceeds through the CHM cells.
This work is based on the demonstration by ptompalski his original code can be viewed here.
chm: A Canopy Height Model (CHM) raster layer. (SpatRaster)
f: A function or fixed number defining the moving window size, defaults to a variable window size based on CHM height (Popescu and Wynne 2004).
dir_out: Directory path where the output GIF and temporary frames will be stored.
gif_out_name: Name of the output GIF file, defaults to "ITD_animation.gif".
buffer: Buffer distance added around the animation frame, defaults to 2.5m.
delay: Delay in seconds between frames in the GIF, defaults to 0.05 (5ms).
circular: Logical, if TRUE, the moving window is circular, defaults to TRUE. Otherwise, window is square.
subset: Logical, if TRUE, only a subset of the CHM cells defined by sub_range is used for animation, defaults to TRUE.
sub_range: Range of indices to define the CHM subset for the animation, defaults to 450:1450.
col_pal: Color palette for the CHM visualization, defaults to scale_fill_viridis_c().
clear_frames: Logical, if TRUE, temporary frame images are deleted after creating the GIF, defaults to FALSE.
skip_cells: Integer, number of CHM cells to skip when creating the animation, defaults to 1 (no skipping).
ttop_size: Size of the points representing tree tops, defaults to 4. (see plot.sf)
ttop_shape: Shape of the points representing tree tops, defaults to 4. (see plot.sf)
ttop_col: Color of the points representing tree tops, defaults to "black". (see plot.sf)
hillshade: Logical, if TRUE, a hillshade layer is created and used as the background, defaults to FALSE.