Overview 1. Aerial LiDAR in Wisconsin (20 minutes) 2. Demonstration of data in CAD (30 minutes) 3. High Density LiDAR (20 minutes) 4. Aerial lidar technology advancements (15 minutes) 5. Q & A
1. Aerial LiDAR in Wisconsin LiDAR basics History and Current Status Recent Improvements Use Cases
What is LIDAR? Light Detection And Ranging Similar to Radar or Sonar but uses an optical source a laser to measure location based on speed of light Produces millions of XYZ points per square mile Aerial Survey Technology Now standard technology for large area topographic mapping
Definitions Point Cloud dataset of XYZ points collected from a LiDAR sensor LAS the most common format for storing lidar point cloud data Bare Earth DEM Digital Elevation Model created using ground class points Returns each pulse from the laser sensor can have multiple returns PPM refers to the density of lidar data, Points Per Meter (square) NPS refers to the point spacing of lidar data, Nominal Point Spacing QL2 LiDAR Quality Level 2, which is the current spec for countywide lidar in WI 3DEP 3D Elevation Program run by USGS to achieve lidar coverage across the US
Typical Datasets produced from aerial LiDAR Classified Point Cloud Bare Earth DEM Hydro Breaklines 2-ft Contours
Common Applications Floodplain Mapping Contour mapping Drainage studies Terrain analysis Feature extraction Engineering planning/design Volumetric measurements
Status Map
Data Access http://www.doa.state.wi.us/documents/dir/land_information/parcel_initiative/county_contacts.pdf Full Resolution datasets Point Cloud DEM Contours Breaklines
Data Access http://relief.ersc.wisc.edu/wisconsinview/form.php Public Domain Derived DEM s
The last 12 years in Wisconsin 2005-09 2010-12 2013-15 2015-17
Current industry specifications USGS: ASPRS: FEMA: USACE:
Current Status
Vertical accuracy specifications County LiDAR in WI Pre-2015 Current Point Density 1 PPM 2 PPM Vertical Accuracy 0.61 feet RMSEz 0.33 feet RMSEz Contour Interval 2-foot 1-foot Specification FEMA/USGS v1.0 ASPRS/USGS v1.2 QL2
Vertical Accuracy Analysis Calibration Control Non-vegetated, open areas Checkpoint Control Non-vegetated Vertical Accuracy Bare Earth Urban Vegetated Vertical Accuracy Swamp Low Grass Forest
Vertical Accuracy Reporting
Major improvements in last 12 years Sensor technology More returns per pulse Faster scan frequency Software advancements IT infrastructure = Better vertical accuracy (2X) Better horizontal accuracy Improved point classification Better representation of terrain Greater feature extraction capability
1 ppm 1 meter DEM
2 ppm 2 foot DEM
Older Lidar Density
Newer Lidar Density
Point Classification Differences
Northern Wisconsin Flooding, July 2016 Aid in emergency management planning Measure the amount of material lost Estimate costs for fill material to rebuild the site Understand how water will flow at this site in the future Help to engineer smarter structures for the site
2. Demonstration in CAD Loading points Breaklines Generating a surface Load existing DEMs Creating contours Contour comparisons Loading orthoimage layer
Sample Dataset
Point Cloud Definitions LAS Classification -
3. High Density LiDAR Platforms and sensors High Density Aerial LiDAR demo in CAD Mobile LiDAR demo in CAD Terrestrial LiDAR (HD Scanning) LiDAR point cloud vs. UAV image matching
High Density LiDAR Platforms
High Density Aerial - DEMO
Mobile LIDAR - DEMO
Terrestrial LiDAR
Terrestrial LiDAR
Terrestrial LiDAR
LiDAR vs UAV image matching
LiDAR vs UAV
LiDAR vs UAV Data voids under vegetation
LiDAR vs UAV
4. Advancements in Aerial LiDAR Single-photon LiDAR (SPL) Geiger-mode LiDAR (GML) Conventional LiDAR systems
High density over large areas?
Advantages of GML and SPL systems Source: Harris
Advantages of Conventional systems
When does SPL or GML make sense? Source: Harris
When does conventional aerial lidar make sense?
Conventional lidar systems advancing too Source: Riegl
Impact on the LiDAR industry
Impact on the LiDAR industry next 5 to 10 years of choice linear mode is always going to be the sensor
Takeaways from today s presentation