6

I typically use Windows-based FUSION to generate grid metrics, which can be used to describe forest structural characteristics. From the FUSION documentation:

GridMetrics computes a series of descriptive statistics for a LIDAR data set. Output is a raster (grid) represented in database form with each record corresponding to a single grid cell.

FUSION and RSAC have excellent documentation and tutorials--for example, page 5 of EXERCISE 5: CALCULATE LIDAR METRICS highlights how to use FUSION to calculate grid metrics such as: count, skewness, cover, 75th percentile value for cell, etc... More details on grid metrics can be found on page 69 of the FUSION documentation.

In an effort to port my LiDAR processing to Linux and open source software, I am curious what functionality PDAL or PCL have for calculating grid metrics?

7

PDAL doesn't provide anything like FUSION's "GridMetrics" at this time. We've been interested in useful statistics or metrics that PDAL could compute for algorithm builders, but we haven't gotten around to implementing anything yet. It would be straightforward to implement a custom PDAL stage to compute these. It will be more productive to ask on the mailing list for more information.

2

You could consider using SPDLib, which has a command called spdmetrics. It can be used to simultaneously calculate multiple vegetation metrics and output them in either raster or vector formats (individual polygons).

There is a tutorial available here that explains how the metrics can be calculated and this XML file provides a full list of the metric primitives and operators.

  • 1
    it links directly to an XML file, so you will probably need to right-click and select 'Copy Link Location' or 'Save Target As' and then open the downloaded file in a text/xml editor. – dmci Jan 4 '16 at 11:38
  • A PDF with a more recent SPDLib tutorial (also includes links to data and example scripts) is available from: spectraldifferences.files.wordpress.com/2013/08/…. This covers metrics amongst other things. – danclewley Jun 14 '16 at 19:55

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