122 lidar

LiDAR data analysis and visualization with whitebox and geemap

Create a new conda env to install required packages:

conda create -n geo python
conda activate geo
conda install -c conda-forge mamba
mamba install -c conda-forge pygis
pip install laspy[lazrs]

Uncomment the following line to install packages in Google Colab.

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# !pip install geemap[lidar]

# !pip install geemap[lidar]

Import libraries¶

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import os
import geemap
import whitebox

import os import geemap import whitebox

Set up whitebox¶

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wbt = whitebox.WhiteboxTools()
wbt.set_working_dir(os.getcwd())
wbt.set_verbose_mode(False)

wbt = whitebox.WhiteboxTools() wbt.set_working_dir(os.getcwd()) wbt.set_verbose_mode(False)

Download sample data¶

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url = "https://github.com/giswqs/data/raw/main/lidar/madison.laz"
if not os.path.exists("madison.laz"):
    geemap.download_file(url)

url = "https://github.com/giswqs/data/raw/main/lidar/madison.laz" if not os.path.exists("madison.laz"): geemap.download_file(url)

Read LAS/LAZ data¶

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laz = geemap.read_lidar("madison.laz")

laz = geemap.read_lidar("madison.laz")

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laz

laz

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str(laz.header.version)

str(laz.header.version)

Upgrade file version¶

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las = geemap.convert_lidar(laz, file_version="1.4")

las = geemap.convert_lidar(laz, file_version="1.4")

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str(las.header.version)

str(las.header.version)

Write LAS data¶

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geemap.write_lidar(las, "madison.las")

geemap.write_lidar(las, "madison.las")

Histogram analysis¶

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wbt.lidar_histogram("madison.las", "histogram.html")

wbt.lidar_histogram("madison.las", "histogram.html")

Visualize LiDAR data¶

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geemap.view_lidar("madison.las")

geemap.view_lidar("madison.las")

Remove outliers¶

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wbt.lidar_elevation_slice("madison.las", "madison_rm.las", minz=0, maxz=450)

wbt.lidar_elevation_slice("madison.las", "madison_rm.las", minz=0, maxz=450)

Visualize LiDAR data after removing outliers¶

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geemap.view_lidar("madison_rm.las", cmap="terrain")

geemap.view_lidar("madison_rm.las", cmap="terrain")

Create DSM¶

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wbt.lidar_digital_surface_model(
    "madison_rm.las", "dsm.tif", resolution=1.0, minz=0, maxz=450
)

wbt.lidar_digital_surface_model( "madison_rm.las", "dsm.tif", resolution=1.0, minz=0, maxz=450 )

In [ ]:

geemap.add_crs("dsm.tif", epsg=2255)

geemap.add_crs("dsm.tif", epsg=2255)

Visualize DSM¶

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m = geemap.Map()
m.add_raster("dsm.tif", colormap="terrain", layer_name="DSM")
m

m = geemap.Map() m.add_raster("dsm.tif", colormap="terrain", layer_name="DSM") m

Create DEM¶

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wbt.remove_off_terrain_objects("dsm.tif", "dem.tif", filter=25, slope=15.0)

wbt.remove_off_terrain_objects("dsm.tif", "dem.tif", filter=25, slope=15.0)

Visualize DEM¶

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m.add_raster("dem.tif", colormap="terrain", layer_name="DEM")
m

m.add_raster("dem.tif", colormap="terrain", layer_name="DEM") m

Create CHM¶

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chm = wbt.subtract("dsm.tif", "dem.tif", "chm.tif")

chm = wbt.subtract("dsm.tif", "dem.tif", "chm.tif")

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m.add_raster("chm.tif", colormap="gist_earth", layer_name="CHM")
m

m.add_raster("chm.tif", colormap="gist_earth", layer_name="CHM") m