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.

In [ ]:

# !pip install geemap[lidar]

# !pip install geemap[lidar]

Import libraries¶

In [ ]:

import os
import geemap
import whitebox

import os import geemap import whitebox

Set up whitebox¶

In [ ]:

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¶

In [ ]:

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¶

In [ ]:

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

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

In [ ]:

laz

laz

In [ ]:

str(laz.header.version)

str(laz.header.version)

Upgrade file version¶

In [ ]:

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

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

In [ ]:

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¶

In [ ]:

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

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

Visualize LiDAR data¶

In [ ]:

geemap.view_lidar('madison.las')

geemap.view_lidar('madison.las')

Remove outliers¶

In [ ]:

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¶

In [ ]:

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

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

Create DSM¶

In [ ]:

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¶

In [ ]:

m = geemap.Map()
m.add_raster('dsm.tif', palette='terrain', layer_name='DSM')
m

m = geemap.Map() m.add_raster('dsm.tif', palette='terrain', layer_name='DSM') m

Create DEM¶

In [ ]:

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¶

In [ ]:

m.add_raster('dem.tif', palette='terrain', layer_name='DEM')
m

m.add_raster('dem.tif', palette='terrain', layer_name='DEM') m

Create CHM¶

In [ ]:

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

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

In [ ]:

m.add_raster('chm.tif', palette='gist_earth', layer_name='CHM')
m

m.add_raster('chm.tif', palette='gist_earth', layer_name='CHM') m

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Last update: 2023-04-06
Created: 2022-07-27