02. Detectable Attributes - VUKOZ-OEL/3d-forest-classic GitHub Wiki

In the current version of the 3D Forest (0.51) the following characteristics can be calculated:

Tree Attributes

  • Position: gives X, Y, Z coordinates of the tree base in the Cartesian coordinates system. More information in section Trees.
  • DBH: this attribute determines diameter at breast height, i.e. the tree stem diameter calculated from a sub-set of points from 1.25 to1.35 m above the tree base. See also: least squares regression and randomized Hough transformation.
  • Height: vertical distance between the tree base and the highest point of the tree, (i.e. the max. difference in Z coordinate in meters).
  • Cloud length: gives the longest distance between two points in the cloud. It is suitable for the length calculation of highly inclined or lying trees.
  • Stem Curve: determines the stem centers and diameters calculated in various heights above the tree base (0.65m, 1.3m, 2m, 3m, etc.).
  • Convex planar projection of the tree: returns polygon with the shortest boundary containing all points of the tree cloud orthogonally projected on the horizontal plane.
  • Concave planar projection of the tree: returns polygon with the smallest area containing all points of tree cloud orthogonally projected on the horizontal plane.
  • The number of tree points: yields the number of points representing a single tree.

Crown Attributes

  • Crown centroid: gives coordinates of the tree crown center position (X, Y, Z) in the Cartesian coordinates system as computed from crown external points. More information in section Crowns.
  • Crown position deviation: returns the crown position deviation from the tree base position. It is defined by distance (m) and direction (°).
  • Crown bottom height: provides the vertical distance (i.e. the difference in Z coordinates in meters) between the tree base position and height of the place where the lowest living branch attaches the main stem.
  • Crown height: computes the vertical distance (i.e. the difference in Z coordinates in meters) between the crown bottom height and its highest point.
  • Crown total height: gives vertical distance (i.e. the difference in Z coordinates in meters) between the lowest and the highest point of the tree crown.
  • Crown volume by voxels: returns crown volume computed from voxels of a given size.
  • Crown volume and surface area by concave polyhedron: computes crown volume and surface area utilizing cross-sections of a given height and concave hull threshold distance.
  • Crown volume and surface area by 3D convex hull: returns volume and surface area of crowns 3D convex hull.
  • Crown intersections: gives volume and surface area of intersecting space between convex hulls of two crowns.