Morris june2015 usiei_updated
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This document discusses lidar technology, including its history, applications, concerns, and trends. It provides an overview of active lidar systems that use laser pulses to measure distance and generate 3D point clouds. Applications mentioned include assessing geodesy accuracy, slope stability, shoreline delineation, beach erosion, and natural disaster impacts. Topobathymetric lidar is discussed for mapping both land and shallow water areas. Challenges of airborne lidar bathymetry are also summarized, such as the need for accurate tides, dealing with water clarity and refraction effects. Recent trends show increasing lidar data availability and uses through organizations like NOAA and its Digital Coast program.
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Morris june2015 usiei_updated
- 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
- 9. Willapa, WA
- 11. Topobathy
- 12. Why Topobathy NOAA NGS Atlantic Coast Mapping Project Lockwoods Folly Inlet, NC 1 mi
- 13. 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
- 15. Trends
- 20. 1997 - 2000
- 32. 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.
- Can’t talk about hazard assessment without talking about the Oso landslide… subsidence measuring.
- Derived shorelines. Have tremendous effects on insurance rates, taxes, law, jurisdiction, etc
- 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)