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Using LiDAR Data within Smallworld. Mark Field – FCSI. Overview. LiDAR – We have heard about it, but what is it? How’s it collected What data is in it Variations of LiDAR data How is it stored in Smallworld Example set of tools - PowerPoint PPT Presentation
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Using LiDAR Data within Smallworld
Mark Field – FCSI
Overview
• LiDAR – We have heard about it, but what is it?– How’s it collected– What data is in it– Variations of LiDAR data
• How is it stored in Smallworld• Example set of tools• How this implementation can be used to
develop useful data
What is LiDAR?
• Light Detection And Ranging– aka Laser Detection And Ranging (LADAR)
• Can be used in side and downward-looking– Laser speed gun, weather “radar”, airborne
• Data is gathered by detecting the reflection of the light– Distance, intensity, return number
• Raw results are “point clouds”
LiDAR Collection Illustration
Source: https://www.e-education.psu.edu/lidar/node/1405
Variations of LiDAR• Raw, Unfiltered Data(LAS format)– Contains noise, artifacts
• Filtered, Classified (LAS format)– Contains point cloud data– Multiple returns– Classified into ground, vegetation, building, etc.
• Ground Points (LAS format)– Contains single “layer” of ground
• Digital Elevation Models (DEM, DTM, TIN)– Rasterized version of ground points
Variations of LiDAR (cont.)
• LAZ– Lossless Compressed LAS
• Categorized XYZ – ASCII– Files separated into single category
Implementation by FCSI
• Expanded FCSI’s N-Dimensional Geometry– 5+ Dimensional TIN Structure (XYZTV)
• TIN Node now contains all LiDAR Data
– X, Y, Z– Intensity– Return– Number of Returns– Scan Direction– GPS Time
– Edge of Flight?– Classification– Scan Angle– User Data– Point Source– Color (RGB)
Example Tools by FCSI
• Point Viewer– Points colored by return, intensity, elevation,
classification– Filter points by return, intensity, classification
• DEM Updater– Update DEM values based off LiDAR
• Manual Feature Extraction
Point Viewer
DEM Update
Elevation Extraction
Issues with LiDAR
• Number of Points is extremely large– 1000’ x 100 ‘ of Missouri contains 560,000 points!– 5000’ x 5000’ 5.3 to 8.2 Million points!– 5.3 Million = 463MB gdb.ds (1MB rwo.ds)
• What will it be used for?– DEM/TIN – Rasterize externally– Ensure data is what you want to use
• Is it classified?• Does it contain non-ground data (multiple returns)?
• External tools do exist that may be more effective
How Can LiDAR Be Used?
• Very accurate terrain models– TINs or DEMs
• Identify features for corridor management– Buildings– Vegetation– Towers, Poles, Lines
Questions?/Contact
• Mark Field• [email protected]• FCSI Booth 19• Cell: 407-376-6105• @mbfbsae90• mbfbsae90