Identifying ground

Purpose:
  • Filter and classify ground points

filters.ground

  • Progressive Morphological Filter [Zhang2003].

  • Exact (slow) and Approximate (fast)

  • Ground only, no other types

Zhang2003

Zhang, Keqi, et al. “A progressive morphological filter for removing nonground measurements from airborne LIDAR data.” Geoscience and Remote Sensing, IEEE Transactions on 41.4 (2003): 872-882.

Ground (execution)

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pdal translate ./exercises/analysis/ground/CSite1_orig-utm.laz \
-o ./exercises/analysis/ground/ground.laz \
smrf \
-v 4

Ground (view)

_images/ground-classified-included.png

Ground (noise)

Noise!

_images/ground-classified-included-side.png

Ground (ground only)

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pdal translate \
./exercises/analysis/ground/CSite1_orig-utm.laz \
-o ./exercises/analysis/ground/ground.laz \
smrf range \
--filters.range.limits="Classification[2:2]" \
-v 4

Ground (denoised first)

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pdal translate ./exercises/analysis/ground/CSite1_orig-utm.laz \
-o ./exercises/analysis/ground/denoised-ground-only.laz \
outlier smrf range  \
--filters.outlier.method="statistical" \
--filters.outlier.mean_k=8 --filters.outlier.multiplier=3.0 \
--filters.smrf.ignore="Classification[7:7]"  \
--filters.range.limits="Classification[2:2]" \
--writers.las.compression=true \
--verbose 4

Ground (view)

_images/ground-filtered.png