Lidar & 3D visualization
Yesterday at Mammoth Cave
GEO 409: Advanced GIS
What did you do over break?
Yesterday's animation from GEOS-16:
Example lab 5
Corner of Limestone and Avenus of Champions: Esports Theater on University of Kentucky’s campus
Pauer Cartography Award
Submissions are open!
Traditional cartography, 3D mapping, and web maps
Let me know if you want to submit.
Geography Enrichment Award
Want to explore a mapping and GIS topic in more detail?
Get paid to explore this topic!
Let me know if you if you are interested.
Python to process data.
Final project theme?
Virtual field trip to
Play 1-10 Chained Rock ⬇️
(Light Detection and Ranging)
with multiple returns and attributes.
Creates a point cloud (massively sampled locations).
Point cloud attributes
x, y, z position
intensity of return
Custom algorithms classify point
Massive sampling of earth's surface by plane.
Uses GPS and IMU (inertia measurement unit) to map point.
While can penetrate canopy, cannot 'see' under solid structures.
I.e., cannot see under our arches, bridges, overhangs.
Can build true 3D model, e.g., see under and inside.
Increasingly available in consumer products.
Airborne + Terrestrial 🤯
The most detailed model of our environment that has ever been made. Hi, digital twin!
Who's collecting data?
Your car, phone, computer, etc.
VR and AR experiences in real places.
You're 'known' more precisely.
Hey, your living room could fit this new chair!
Massive file size
State divided into 46,105 tiles
with one tile ~ 500 MB.
Difficult to visualize
How to handle these file sizes?
Code most of the processing in ArcPy
to output raster derivatives
and browser optimized point clouds using video game technology.
9 GB point cloud > 250 MB raster
Abundant uses of lidar justify the technology
and our careful workflow.
What use might you discover?
The most detailed, comprehensive digital elevation model of our environment that has ever been made,
Flooding, landslides, geological hazards, etc.
Just look at the shaded relief maps you have already made.
New detail at archeological sites.
Lidar can penetrate dense canopy
and reveal details about past built environments.
Ancient Mayan cities
Above ground features captured, like vegetation,
to model biomass, carbon, etc.
Also used in precision agriculture.
Delineating tree crowns in forest
What can you do with a detailed model of a city?
Reduce greenhouse emissions?
Put solar panels on buildings with most insolation.
Sanborn lidar NYC
Kentucky Aerial Photography & Elevation Data (KYAPED) program
Collected during leaf-off conditions
no snow and water levels at or below normal.
Point cloud has 2.23-foot point horizontal spacing.
Access data in 5k ft x 5k ft tiles, 100–500 MB.
Includes high-resolution aerial imagery.
Create high-resolution elevation products for bare-earth conditions.
A statewide 5-ft resolution DEM is now available.
Two phases show different times.
Algorithms classify point
Need to filter for ground points.
All (non-noise) points give us tree height
| KY classes | Meaning| |-------------|-----------:| |1 |Processed, but Unassigned (above ground features) | |2 |Bare-earth or ground| |7 & 18 |Noise (e.g., birds. Can be low or high, manually identified, if needed)| |9 |Water| |10 |Ignored Ground (Breakline Proximity)|
Heads-up digitizing to enforce hydro rule
Classify bridges and noise.
Field measurements to verify accuracy
Most measurements within .2 ft
LAS file format
format most common in GIS
LAZ file format
A compressed LAS file
Most common storage format
Need a separate utility to decompress and use in ArcGIS Pro.
laszip.exe include in our tools folder
Explore tiles and download data
Create a folder in your root GIS folder called
In that folder, create a folder called
Download two adjacent tiles to that folder
Make sure they are the same Phase, i.e., same version.
Drag and drop the LAZ file, one by one, onto the laszip.exe application
Verify that you have two LAS files.
Create LAS dataset
Treat multiple tiles as a single layer.
Enter Python and the Lesson-05.ipynb
[Create LAS dataset](https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/create-las-dataset.htm) ```py # Create LAS dataset arcpy.CreateLasDataset_management (input_las_files, output_dataset) ```
Point cloud Derivatives
Airborne point clouds can be reduced to high-resolution raster imagery.
Digital Elevation Model
Most often bare-earth surface
Point cloud class code 2
Digital Surface Model
Includes the reflected surface
buildings, trees, bridges, etc.
Point cloud class codes 1, 2, 9, 17
Digital Terrain Model
with vector features to model surface features
lines for streams, polygons for lakes, etc.
Point cloud class codes 2 and digitized features
Steps in model creation
Filter point cloud
Make LAS dataset layer (temporary)
Rasterize LAS dataset layer
[Make LAS dataset layer](https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/make-las-dataset-layer.htm) ```py # Make LAS dataset layer arcpy.MakeLasDatasetLayer_management (in_Dataset, out_Dataset, list_of_points) ```
[LAS Dataset To Raster](https://pro.arcgis.com/en/pro-app/latest/tool-reference/conversion/las-dataset-to-raster.htm) ```py # LAS Dataset To Raster arcpy.MakeLasDatasetLayer_management (in_Dataset, out_image, "#", "#", "#", "#", cell_size) ```
[Hillshade](https://pro.arcgis.com/en/pro-app/latest/tool-reference/3d-analyst/hillshade.htm) ```py # Make Shaded Relief arcpy.HillShade_3d(out_image, hillshade, 270, 50, False, 2) ```
Colorize point cloud
Apply color from overlapping imagery.
Can create realistic view of area of interest.
Creates new LAS files
Doubling your project size.
[Colorize LAS](https://pro.arcgis.com/en/pro-app/latest/tool-reference/3d-analyst/colorize-las.htm) ```py # Colorize LAS files bands = 'RED Band_1; GREEN Band_2; BLUE Band_3' arcpy.ColorizeLas_3d (in_dataset, in_raster, bands, out_dir) ```
Connect Kentucky ArcGIS Server
Add server to new ArcGIS Pro projects
Explore 3D Kentucky
Start in lesson
Run notebook to process data (a few times to practice)
Start with a small buffer distance, e.g. < 1000 feet
Design 3D map and animation
to the world
with an image and a video animation.
Practice making a web page?