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Fit a crown & metrics

Fit a simple geometric shape to a tree's crown and read off per-tree metrics — tree height, crown volume, crown center, and crown dimensions. Each fitted crown becomes a mesh in the scene with its statistics attached, and you can export every crown to a CSV table (one row per crown) that records the shape's fit parameters, not just its statistics.

Fitting is done per scan, and — for a cloud that carries tree labels — per tree within a scan. You can select several scans at once and fit them all in one run.

Inputs

Each scan you fit must be a segmented individual tree with the ground handled. Phytograph reads the classification labels the segmentation tools write and adapts the fit to what's present:

Step Label Effect on the fit
Segment ground points ground_class Ground points are excluded and give the height baseline.
Separate leaf and wood wood_class The crown is fit to the leaf points only (trunk/branches excluded).
Segment individual trees tree_instance One crown is fit per tree in the cloud.

Missing labels are ambiguous — you'll be warned

If a scan has no ground / tree / wood labels, Phytograph can't tell whether you segmented that step manually (removed the ground, split one tree per cloud) or simply forgot to run it. So a missing label raises a warning in the setup modal rather than silently proceeding or blocking you:

  • No tree labels → the fit assumes the cloud is a single, manually-segmented tree. If it actually holds several trees or unsegmented data, segment the trees first (or split them into separate clouds).
  • No ground labels → tree height is measured from the tree's lowest point as the ground baseline. Make sure the ground was removed / the base sits at ground level, or segment the ground.
  • No leaf/wood labels → the crown includes trunk and branch points. Separate leaf and wood for a leaf-only crown.

A scan is only disabled in the picker when it's structurally unusable (too few points, or no backing data).

Run the fit

  1. Select one or more scans, then open Tools → Fit Crown & Metrics (or press Cmd/Ctrl+K and search "crown").
  2. Choose the scans to fit. Ineligible scans are grayed out with a reason; scans missing labels show a warning banner but stay fittable.

  3. Pick a crown shape:

    Shape Best for
    Ellipsoid Rounded, broadleaf crowns (a good default).
    Rectangular prism Reporting width × depth × height directly.
    Cone Conifers and young trees (apex at the crown top).
    Alpha shape Faithfully hugging an irregular crown outline.

    Ellipsoid, prism, and cone are fit axis-aligned (upright and square to the world axes), so the reported dimensions read as width × depth × height.

  4. Set the fuzziness (range 0–0.5, default 0.2). 0 bounds every point (including a lone branch shooting outside the crown); higher values trim the outermost points so an outlier branch doesn't inflate the shape with empty space. See Crown metrics for how the trim works.

  5. (Alpha shape only) Optionally override the alpha radius — leave blank for automatic.
  6. (Optional) Tick Export crown table to CSV. Give the export a file name (it defaults to the first selected scan's name), and — for an alpha shape — pick the crown mesh format (OBJ, PLY or STL). The line under the name field previews exactly what will be written.
  7. Click Fit crowns.

Results

Each fitted crown is added to the Meshes panel. Expand a crown mesh to see its metrics:

  • Tree height — crown top minus the ground baseline.
  • Crown volume — the fitted shape's volume.
  • Crown center — the center of the fitted shape, in world coordinates.
  • Crown dimensions — width × depth × height of the fitted shape.
  • Surface area and points used.

The source scans are hidden after a successful fit so the crowns are visible; re-show them from the Scans panel any time.

CSV export

With Export crown table to CSV ticked, Phytograph writes one row per crown when the fit completes. Each row carries the crown's metrics and the parameters that define its shape — an ellipsoid's semi-axes, a cone's base radius and height — so a row is enough to rebuild the solid. See File formats for the column list.

Alpha shapes also write a mesh

An alpha shape has no such parameters: it's a concave hull, so its geometry is the result. Those crowns therefore get a mesh file written alongside the CSV, and the row's mesh_file column names it.

Because that means more than one file, an alpha export asks you to choose a folder rather than a save location; the CSV and every crown mesh are written into it together. The mesh file names are <file name>_<scan>_tree<N>.<ext> (or …_crown when the whole cloud was fitted as a single tree).

The other three shapes need no mesh — their parameter columns already describe them completely — so they leave mesh_file empty and are saved through the ordinary save dialog as a single CSV.

Exporting a crown mesh on its own

Any fitted crown is a normal mesh in the scene, so you can also select it and export it from the Export window at any time — see Import & export. The mesh_file column exists so that a table stays a complete record without that extra step.

See also