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"Why LiDAR?" Presentation

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Sanborn's LiDAR Team Presentation

Sanborn's LiDAR Team Presentation

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  • 50khz = 50,000 points per second
  • How is this controlled
  • All LiDAR formats can be viewed in the same software

Transcript

  • 1. LiDAR- Why Do We need it? Benefits of Having High Resolution LiDAR Data September 16 th , 2009 GIS in The Rockies Presented by: Jamie Young General Manager – LiDAR services
  • 2. LiDAR Li ght D etection A nd R anging Aerial sensor Collects/scans data, either photons (reflected light) or laser pulses Aerial GPS (Global Positioning System) Based on GPS satellite triangulation, measures the location of the aircraft up to 0.1 second. IMU (Inertial Measurement Unit) Measures attitude (pitch/yaw/roll) of aircraft every .002 second. Ground GPS Measures the location of the aircraft up to 0.1 second relative to a known ground position
  • 3. LiDAR Collection Sensor for Your project
    • Sensors
      • Optech
      • Leica
      • Toposys
      • Reigl
    • Multi-pulse versus Single Pulse
      • Single Pulse =150khz
      • MPia – Multi-Pulse in air = 300khz
  • 4.
    • Standard LIDAR – 1.4m point spacing
      • 18.5 cm RMSEz, 1.0 m Horizontal
      • General-use, Meets most needs for LiDAR-based DEM
    • FEMA Compliant LIDAR – 1.4m point spacing
      • 18.5 cm RMSEz, 1.0m Horizontal
      • FEMA Map Modernization specified product
      • Meets FEMA guidelines and specifications for LiDAR-based DEM
    • High Density LIDAR – 0.7m point spacing
      • 15 cm RMSEz, 0.5m Horizontal
      • Special use, high accuracy and point concentrated data
      • Meets most needs for LiDAR-based DEM in very dense vegetation and terrain constrained areas
    • High Accuracy LiDAR – 0.7m or more Point spacing
      • 9.24 cm RMSEz, 0.5 Horizontal
      • Supplemental 1 foot accuracy specifications
      • 50% overlap for very dense vegetation
      • Requires very good calibration: Keep overlap
    Typical LiDAR Products Standard, FEMA, High Density
  • 5. Additional LiDAR products
    • Data collection as required by client
    • Breaklines products
    • Contour products
    • Low Density Collection
      • 2-4 meter point sample density
    • Very High Density Collections
      • 20-40 points per meter
    • 3-D Building extraction
      • 3-D Wire frames
      • 3-D Building polygons
  • 6. Additional LiDAR products
    • Clients requiring Additional Classification
      • Water
        • Smooth water bodies
      • Vegetation
        • Low
        • Medium
        • High
      • Buildings
        • Points
        • Foot prints
  • 7. Sanborn Developed Water Body Classification Lake on 7.5 quad map Lake before classification and elevation averaging Lake after classification and elevation averaging ARC surface model
  • 8. Roads 1.4 meter Density Profile at 1.4 meter
  • 9. Road 0.7 Meter Profile at 0.7 meter
  • 10. Road 0.3 Meter Profile at 0.3 meter
  • 11. Best Practices
    • Planning
      • relief
      • Vegetation
      • Application
    • Collection
      • Calibration
      • Control
      • Check Points
      • Field verification
    • Processing
      • Filtering
      • Manual editing
      • Smart editing
    • QA/QC
  • 12. Accuracy Issues Calibration – Process to help verify the Project Data Relative Accuracy of the data is critical – should be able to achieve under 10cm RMSEz and most cases under 5 cm RMSEz Verification of LiDAR Data is critical Manufacture need to listen to LiDAR vendors concerns: Hardware Error Intensity issues
  • 13. Checking Calibration DZ ortho - GeoCue
  • 14. LiDAR Accuracy Standards Things to Consider
    • Accuracy is dependent on:
    • Flying height
    • Sensor parameters
      • Rep Rate
      • Scan Angle – 10 degree of scan angle?
      • Scan frequency
    • System accuracy
    • Terrain
    • Vegetation
    • Data processing
    • and more…!
  • 15. LiDAR Data Accuracy
    • Data meets RMSEz and accuracy requirements
    • Data does not edge match
    • Why?
    • Large Collections
    • Small Collections
    • What can we do?
  • 16. LiDAR Post-processing
    • Development of Production Work Flow to facilitate large Volumes of data
    • IT infrastructure to handle large volumes of data
    • QC processes through out the workflow
    • Latest Filtering Processes and Software packages to ensure the best product.
    • Manual Edit/QC on all Tiles – We look at everything
    • Localized Filtered data based on characteristics of data
    • Internal accuracy assessment on all projects
    • Processes to deal with “Corn rowing”
    • GeoCue Work Flow
    • SC Stereo Pairs and Orthos to facilitate editing process and breakline process
  • 17. LiDAR Software and Viewers Production Software
    • ESRI
      • ARCGIS ®
      • 3D Analyst ™
    • QCoherent
      • LP360
    • Microstation
      • Terrasolid
      • Terrascan
    • Virtual Geomatics
      • New Bore site Total
    • GeoCue
    • More…
  • 18. ROI
    • I talked with several LiDAR Users
      • Very difficult to get information….!!!!
      • estimates that their initial ROI is
      • $1 spent = $4 to $5 return?
      • What they do know is that they get their money back
      • Why?
    • Much more detailed elevation model (NED)
    • Many uses and applications
    • Shelf Life
    • Find Things they did not see before
      • Karst formations in Alaska
      • Sink Holes in Iowa
      • Archeological sites in Kansas
  • 19. What Else What clients have to say…
      • Less expensive? – more economical than traditional surveying or Photogrammetry
      • Faster data? much more detailed
      • Collection around the clock
      • No AT, orthorectification or mosaicing required
      • Reliable terrain data –penetrates canopy
      • Non-intrusive – no land access required for paneling or surveying
      • More accurate then auto-correlation
      • Multiple uses
  • 20. What Else?
    • Clear shortcomings in existing elevation data sets that make shareholders tasks impossible to complete
    • LiDAR lifespan
      • Most states -10 years
      • FEMA -15 to 20 years
    • Current elevation data does not meet business needs
    • Consider different resolutions in different areas to get most money out of collection.
    • Better, cheaper, faster?
    • Remote assess to some regions a concern. Is it here?
  • 21. LiDAR Programs
    • County Updates
      • Gwinnett County, Georgia –Every Year
      • PIMA County, AZ – Every 2 years
    • State Programs
      • Iowa
        • Full state in 3 years
      • South Carolina
        • Buy ups – Spec ups – additional products
      • North Carolina
        • 1999-2002 – 2 to 5 meter data
        • 2009-2011 – 1.4 meter
  • 22. What else?
    • Consider including many agencies to spread the cost
    • Determine the best resolution for all
    • How do you prioritize collection?
      • Population or money usually does this
    • Set up a contracting vehicle or use an existing one
    • Lastly- QA/QC cost to make sure your data is good
  • 23. LiDAR BLOG Submit your LiDAR questions... http://lidarblog.wordpress.com
  • 24. Thank You! and Questions Graphics provided by Leica