comparative_shortest_path

The function performs a Dijkstra algorithm on a 3D voxel file to assign
every voxel to the closest seed point using the igraph package.

Functionality for segmenting individual trees from a forest stand scanned with a close-range (e.g., terrestrial or mobile) laser scanner. The complete workflow from a raw point cloud to a complete tabular forest inventory is provided. The package contains several algorithms for detecting tree bases and a graph-based algorithm to attach all remaining points to these tree bases. It builds heavily on the 'lidR' package. A description of the segmentation algorithm can be found in Larysch et al. (2025) <doi:10.1007/s10342-025-01796-z>.

Julian Frey

CspStandSegmentation

Comparative Shortest Path Forest Stand Segmentation from LiDAR
Data

Zoe Schindler

comparative_shortest_path function

<dl><dt>vox</dt>
<dd>a LAS S4 element with XYZ voxel coordinates in the @data slot.</dd>
<dt>adjacency_df</dt>
<dd>a data.frame with voxel ids (row numbers) in the first
column and a neighboring voxel ID in the second column and the weight
(distance) in the third column. Might be generated using the dbscan::frNN
function (which requires reshaping the data).</dd>
<dt>seeds</dt>
<dd>seed points for tree positions.</dd>
<dt>v_w, l_w, s_w</dt>
<dd>weights for verticality, linearity spericity see
<code>csp_cost_segmentation</code></dd>
<dt>N_cores</dt>
<dd>Number of CPU cores for multi-threading</dd>
<dt>Voxel_size</dt>
<dd>Edge length used to create the voxels. This is only
important to gain comparable distance weights on different voxel sizes.
Should be greater than 0.</dd></dl>

Arguments

Julian Frey &lt;julian.frey@wwd.uni-freiburg.de&gt;

Author

helper function for csp_cost_segemntation — comparative_shortest_path

<dl>

<dt>vox</dt>
<dd>a LAS S4 element with XYZ voxel coordinates in the @data slot.</dd>


<dt>adjacency_df</dt>
<dd>a data.frame with voxel ids (row numbers) in the first
column and a neighboring voxel ID in the second column and the weight
(distance) in the third column. Might be generated using the dbscan::frNN
function (which requires reshaping the data).</dd>


<dt>seeds</dt>
<dd>seed points for tree positions.</dd>


<dt>v_w, l_w, s_w</dt>
<dd>weights for verticality, linearity spericity see
<code>csp_cost_segmentation</code></dd>


<dt>N_cores</dt>
<dd>Number of CPU cores for multi-threading</dd>


<dt>Voxel_size</dt>
<dd>Edge length used to create the voxels. This is only
important to gain comparable distance weights on different voxel sizes.
Should be greater than 0.</dd>

</dl>

comparative_shortest_path: helper function for csp_cost_segemntation

Description

Usage

Value

Arguments

Author

See Also