Extracting DBH, Height, and Volume from rayextract_trees.txt Outputs

[msacee2012-a11y]

Hello,

I have successfully used the rayextract trees tool to segment a sample of 45 trees from a large-scale TLS/ALS dataset. The process generated three expected outputs:

• A segmented point cloud (.ply)
  

• A mesh model of the trees (.ply)
  

• A comprehensive text file (.txt)
  

I am now at the stage of analyzing the individual tree metrics for my biomass estimation study. Specifically, I am looking to extract the DBH (Diameter at Breast Height), Total Height, and Volumetric Data for each of the 45 isolated trees. Upon reviewing the .txt output, I am having some difficulty identifying which columns or data headers correspond to these specific forest factors.

My questions are:

1. Does the .txt file follow a specific header format (e.g., ID, X, Y, Z, Girth, Height, Volume)? If so, could you clarify the units and order of these parameters?
2. Are there any recommended Python coding to get each and individual tree information (DBH, Height and Volume) in a table?
3. Does the text file report the volume based on the voxel reconstruction or the generated mesh surface?

Thanks in advance.

[thomas-lowe]

Hi,

1. it is an extensible format but is fully specified on the second line of the txt file. The output from rayextract trees is however always the same: x,y,z,radius,parent_id,section_id (with a space separator between each cylindrical segment of the tree). All units are SI.
2. the main thing you want in order to extract more information is treetools, if you are using raycloudtools docker it should already be installed. You can then run treeinfo XXX_trees.txt which will save an _info.txt trees file containing per-tree data at the start of each line:
   height,crown_radius,dimension,monocotal,DBH,bend,branch_slope, and then per-segment extra data: volume,diameter,length,strength,min_strength,dominance,angle,children.
   These are described in the help if you just type treeinfo . To pull it into a table most spreadsheet software can import comma delimited text. Though the trees files also use space and new line as delimiters so you'll need to write a python file if the spreadsheet can't cope with that.
3. the volume is the cylinder volumes on each segment and the total cylinder volume on segment 0 (the root segment), so it is inaccurate where there are overlaps between cylinders.

You can also report per-layer volume and extra branch data as extra parameters to treeinfo.

Also see the README.md in treetools for the file format.

[msacee2012-a11y]

Thank you very much for the suggestions and advise.

[tim-devereux]

Just adding to Tom's comment -

I made this repo to load treefiles into Pandas for analysis:
https://github.com/tim-devereux/PyTreeFile/tree/main

There's also treefile support in this R package:
https://github.com/lmterryn/ITSMe

One thing worth noting on DBH - the values are derived from the final mesh rather than directly from the point cloud, so I'd recommend doing some manual validation before relying on them. It can underestimate DBH on highly tapered trees. This is discussed in this paper:

Devereux, T., Lowe, T., Rivory, J., Reckziegel, R. B., Calders, K., Aryal, R. R., Eaton, G., Cooper, Z., Levick, S., Phinn, S., & Woodgate, W. (2026). RayExtract: A fast, scalable method for tree volume reconstruction from terrestrial laser scanning. Remote Sensing of Environment, 334, 115162. https://doi.org/10.1016/j.rse.2025.115162

If you decide you need point-based DBH estimates, the R package above has methods for that or if you prefer Python, this package handles DBH:
https://github.com/3DFin/dendromatics

[msacee2012-a11y]

Thanks a lot for the cooperation.