Lidar Breakdown - ESRI SE
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This document discusses lidar technology, including its history, uses, trends, and data availability. It provides an overview of active lidar systems that use laser ranging to produce 3D point clouds with over 400,000 pulses per second. It reviews the evolution of lidar since the 1960s and covers various applications like coastal zone management, shoreline delineation, and natural disaster assessments. The document also addresses concerns about accuracy and data formats. Additionally, it outlines trends showing increasing lidar coverage over time and the goal of a nationwide elevation dataset by 2020. Maps are presented showing the quality and extent of existing and planned topobathymetric lidar coverage.
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Lidar Breakdown - ESRI SE
- 1. Lidar Breakdown Concerns, Trends & Availability Eric Morris ESRI Southeast User Conference May 4th , 2015
- 2. Active System •Uses laser ranges, scan angle & positional IMU data to produce x,y,z •Post-processing costly •“point clouds” •>400K pulses/sec Basics of Light Detection and Ranging
- 3. A (Brief) History of Lidar • 1960s – Apollo landings • 1977 – NOAA/NASA AOL • 1993 – Airborne GPS & IMU • 2003 – ASPRS LAS 1.0 format (open source) • 2010 – NEEA • 2012 – U.S. Interagency Elevation Inventory • 2014 – 3DEP • ~2020 – GEDI
- 4. Concerns Geodesy Vertical & Horizontal Accuracy
- 5. RMSEZ & ρ
- 6. Raw Data Raw DEM ASCII, LAS, LAZ, ZLAS
- 7. Evolution of Elevation Data
- 9. Why we need lidar
- 10. DSM DTM
- 13. Coastal Zone Management Great South Bay, Long Island, NY
- 16. Willapa, WA
- 17. NOAA Lidar
- 18. Topobathy
- 19. Why Topobathy Tampa Bay, FL
- 20. Why Topobathy 70 m NOAA-NGS Post-Sandy Atlantic Seaboard Mapping Project Avalon, NJ
- 21. Airborne Lidar Bathymetry (ALB) • Applicable to oceans, rivers, lakes • Tides • Snell’s Law • Water Clarity • Eye safety • Air Space • Refraction “Requires more everything” Tampa Bay, FL
- 23. Trends
- 29. 1995 - 2000
- 30. 2001 - 2003
- 31. 2004 - 2006
- 32. 2007 - 2009
- 33. 2010 - 2012
- 34. 2013 - 2015
- 35. Quality Level
- 40. www.coast.noaa.gov/digitalcoast Eric L. Morris Eric.Morris@NOAA.gov Questions? Special Thanks: Kirk Waters, PhD, Applied Sciences, NOAA OCM Amar Nayegandhi, Director of Remote Sensing, Dewberry Chris Parrish, PhD, formerly of NOAA NGS and CCOM-JHC, now at Oregon State Univ.
Editor's Notes
- Chris Parrish’s “simple calculation of lidar”
- Rangefinders used to help Apollo program land on moon. Atmospheric Oceanic Lidar (AOL) Global Position Systems (GPS) Inertial Measurement Unit (IMU) American Society of Photogrammetry and Remote Sensing (ASPRS) LAS – LASer file USIEI 3D- Elevation Prgram Global Ecosystem Dynamics Investigation (GEDI) 1960s – lunar laser ranging (to aid Apollo landing) 1977 – NOAA/NASA AOL looked to the clouds 1993 – GPS & IMU allowed accurate airborne use 2003 – ASPRS LAS 1.0 format (open source) 2010 – National Enhanced Elevation Assessment (NEEA) 2012 – U.S. Interagency Elevation Inventory 2014 – 3DEP ~2020 – GEDI – worldwide canopy at 1 m
- What constitute a concern… mostly what would degrade data quality or hinder collections. Types of data, products. Not going to talk about Geodesy too much, which is a major component of sharing data, because so many people work with different datums and projections. NOAA OCM, NGS and OCS relay on geodesy to be exact, otherwise the data is no longer up to contract and project required accuracies. Explaining h.a. – so good at this point, only a relative check is necessary for most projects due to the Continuously Operating Rerefernce Stations (CORS). The problem for remote sites means gaining basestation data during collection. No matter the basestation situation, Real time-kinematic RTK points coincident is the best way to correct/calibrate the acquired data but also allows for accuracy checks. Pic of me doing field collection for accuracy assessments. 3-D graph shows that the slope of a surface will affect it’s exact accuracy. As the slope increases, the slope increases, that’s why it’s important to get RTK across the x,y,z range of the project area
- QL levels, part of the NEEA assessment to figure out what counties, consortiums, regions, states, national groups need. It was decided that even though QL1 (for topographic data is acquirable, QL3 is the most cost efficient and most worthwhile for 3-5 year cycles. Price estimate of $252.67 per sq mi. 2,644 sq mi for Snohomish = 668K, but the canopy density here would require the QL1 to get the adequate ground density, $547 per sq mi. 1.4 million, double.
- Raw collected format… ascii text, comma delimited. Raw dem, no extra processes, for quick delivery. Only plane allowed to fly over the site, flown immediately following. Collected imagery along with this.
- From profile view to stereo derived photogrammetric contours.
- Elevation.
- DSM, 1st returns basically. DSM is a macro, algorithm derivative of all returns to find the terrain, can have remnants of buildings and vegetation.
- Can’t talk about hazard assessment without talking about the Oso landslide… subsidence measuring.
- Habitat restoration in New York. Input into the Threatened and Endangered Species Geodatabase
- Derived shorelines. Have tremendous effects on insurance rates, taxes, law, jurisdiction, etc
- USGS Coastal Marine Geology Program office. Able to collect bathymetry and topographic lidar together.
- Coastal, but also riverine, no so good in lacustrine/palustrine waters, must be collected as MLLW or MHHW. Light travels slow in water (snell’s law). Backbays are easier to get because of water clarity, higher frequency causes unsafe eye distances, air space along airports and metropolises, refraction (finding where refraction need to be applied – enter IR imagery collection)