55 lidar

LiDAR data analysis and visualization with whitebox and leafmap

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 [1]:

# !pip install leafmap

# !pip install leafmap

In [2]:

# !pip install laspy[lazrs]

# !pip install laspy[lazrs]

Import libraries¶

In [3]:

import os
import leafmap
import whitebox

import os import leafmap import whitebox

Set up whitebox¶

In [4]:

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)

Downloading WhiteboxTools pre-compiled binary for first time use ...

Decompressing WhiteboxTools_linux_amd64.zip ...

WhiteboxTools package directory: /home/runner/miniconda3/envs/test/lib/python3.11/site-packages/whitebox
Downloading testdata ...

Out[4]:

0

Download sample data¶

In [5]:

url = "https://open.gishub.org/data/lidar/madison.zip"
filename = "madison.las"

url = "https://open.gishub.org/data/lidar/madison.zip" filename = "madison.las"

In [6]:

leafmap.download_file(url, "madison.zip", unzip=True)

leafmap.download_file(url, "madison.zip", unzip=True)

madison.zip already exists. Skip downloading. Set overwrite=True to overwrite.

Out[6]:

'/home/runner/work/leafmap/leafmap/docs/notebooks/madison.zip'

Read LAS/LAZ data¶

In [7]:

laz = leafmap.read_lidar(filename)

laz = leafmap.read_lidar(filename)

In [8]:

laz

laz

Out[8]:

<LasData(1.3, point fmt: <PointFormat(1, 0 bytes of extra dims)>, 4068294 points, 2 vlrs)>

In [9]:

str(laz.header.version)

str(laz.header.version)

Out[9]:

'1.3'

Upgrade file version¶

In [10]:

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

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

In [11]:

str(las.header.version)

str(las.header.version)

Out[11]:

'1.4'

Write LAS data¶

In [12]:

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

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

Histogram analysis¶

In [13]:

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

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

Out[13]:

0

Visualize LiDAR data¶

In [14]:

leafmap.view_lidar("madison.las")

leafmap.view_lidar("madison.las")

Remove outliers¶

In [15]:

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)

Out[15]:

0

Visualize LiDAR data after removing outliers¶

In [16]:

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

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

Create DSM¶

In [17]:

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 )

Out[17]:

0

In [18]:

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

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

Visualize DSM¶

In [19]:

m = leafmap.Map()
m.add_raster("dsm.tif", palette="terrain", layer_name="DSM")
m

m = leafmap.Map() m.add_raster("dsm.tif", palette="terrain", layer_name="DSM") m

Out[19]:

Create DEM¶

In [20]:

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)

Out[20]:

0

Visualize DEM¶

In [21]:

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

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

Out[21]:

Create CHM¶

In [22]:

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

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

In [23]:

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

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

Out[23]: