Hawaii LIDAR Datasets
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Data Discovery Day

Data Discovery Day
03/06/2008
Craig Clouet
ESRI

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Hawaii LIDAR Datasets Hawaii LIDAR Datasets Presentation Transcript

  • HIGICC – Data Discovery Day LiDAR: What it is, How to use it Where to get it Craig Clouet & Mathew Barbee Honolulu, Hawaii 2008
  • Agenda • What is LiDAR – Craig Clouet – Types – Data collection & storage • LiDAR Applications – Matt Barbee UH • LiDAR Data Availability – Craig Clouet
  • Hand-held Laser technology
  • – LiDAR stands for Light Detection and Ranging. The system is mounted in an aircraft and is comprised of three primary components: – Laser - collects 50 thousand pulse points per second and records a measurement approximately every 1.5 feet – IMU – a military grade inertial navigation system which measures the movement of the aircraft in three axis 250 times per second. • Kinematic GPS – Receivers log raw data at one second intervals both on the ground and on the aircraft providing extremely precise positioning every one second.
  • Three Main Types of Commercial LiDAR Systems Topographic Mapping SHOALS Terrestrial
  • Topographic Mapping
  • The LiDAR Set-up Portable for Shipping & multiple Platforms
  • SHOALS
  • Terrestrial
  • The terrestrial LIDAR technique, or 3D laser scanning as it is commonly known, consists of sending and receiving laser pulses to build a point file of three-dimensional coordinates of virtually any surface. The time of travel for a single pulse reflection is measured along a known trajectory such that the distance from the laser, and consequently the exact location of a point of interest can be computed. In addition, some lasers use a color sensor to obtain additional visual data on points located both within and outside of laser range. Given the rapid rate of data collection from the newest state of the art topographic laser scanning systems, the location of up to 12,000 surface points can be collected in one second. Thus, an entire surface, be it a building, a cliff face, or a sand bar can be surveyed quickly and accurately. The point file from a given scan is typically transformed into a three-dimensional surface so that cross-sections and volumetric calculations can be performed between consecutively scanned surfaces.
  • Data Structure and Uses of the Elevations
  • LiDAR Point Cloud
  • LiDAR point spacing Determined at Contract DEM spacing Created by user
  • Level of Accuracy and Interpolation
  • Example of the Grid Spacing at 5ft
  • Elevations at each 5 ft cell
  • The Point Cloud
  • Lots of actual data measurements Not too much Interpolation
  • File Formats
  • Or ENZI E N Z I
  • LAS Format The LAS file format is a public file format for the interchange of LIDAR data between vendors and customers. This binary file format is a alternative to proprietary systems or a generic ASCII file interchange system used by many companies. The problem with proprietary systems is obvious in that data cannot be easily taken from one system to another. There are two major problems with the ASCII file interchange. The first problem is performance because the reading and interpretation of ASCII elevation data can be very slow and the file size can be extremely large, even for small amounts of data. The second problem is that all information specific to the LIDAR data is lost. The LAS file format is a binary file format that maintains information specific to the LIDAR nature of the data while not being overly complex.
  • Digital Elevation Models A method to Store Continuous Topographic data Raster
  • Shaded Relief A visual graphic Representation of topography
  • Contours Graphical Representation of elevation Vector format
  • Accuracy 1 National Geodetic Survey, Retrieval Date = JANUARY 13, 2006 TU0562 *********************************************************************** TU0562 DESIGNATION - BATH RM 3 TU0562 PID - TU0562 TU0562 STATE/COUNTY- HI/HONOLULU TU0562 USGS QUAD - KAENA (1983) TU0562 TU0562 *CURRENT SURVEY CONTROL TU0562 ___________________________________________________________________ TU0562* NAD 83(1993)- 21 34 39.91926(N) 158 15 46.06795(W) ADJUSTED TU0562* LOCAL TIDAL - 2.674 (meters) 8.77 (feet) ADJ UNCH TU0562 ___________________________________________________________________ TU0562 EPOCH DATE - 1993.62 TU0562 LAPLACE CORR- 4.63 (seconds) DEFLEC99 TU0562 GEOID HEIGHT- 14.90 (meters) GEOID99 TU0562 TU0562 HORZ ORDER - SECOND TU0562 VERT ORDER - FIRST CLASS II TU0562 TU0562.The horizontal coordinates were established by classical geodetic methods TU0562.and adjusted by the National Geodetic Survey in December 1998. TU0562.The horizontal coordinates are valid at the epoch date displayed above. TU0562.The epoch date for horizontal control is a decimal equivalence TU0562.of Year/Month/Day. TU0562 TU0562.The orthometric height was key entered from printed documents TU0562.and not key verified.
  • Location of NGS Reference Sites
  • Comparison of NGS Elevation and LiDAR Reported Values in Feet 10 Foot Radius from Control point
  • Lidar Products • Example of Airborne 1 deliverables
  • Bare Earth
  • Extracted Feature
  • Bare Earth
  • Extracted Feature
  • Vegetation Response
  • Using the Intensity Return Soil State and Moisture
  • Examples
  • Tile Structure
  • Data is in Geographic Coordinates
  • Issues • Clouds • No Data • Resolution • Vegetation • Interpolation of point features
  • No Data Interpolation Effects
  • Resolution
  • Vegetation
  • Point Features
  • Management of data •Ability to store in original spacing and use where and when as needed. Limitations • Large data sets • Time to process • Requires extra software
  • Tools • ArcGIS works with LiDAR, at the 9.2 release the tools are more robust and easier to use. • There are many other 3rd party and stand alone software solutions. Some free and some commercial.
  • LiDAR Tools
  • LiDAR Tools
  • LiDAR Tools
  • Applications Matthew Barbee
  • LiDAR Resources
  • Coverage in Hawaii
  • Coverage in Hawaii State State USGS NGA - USGS State State
  • USACE ‘s message 1. LIDAR data acquired for local agencies (ie. they paid for the data) Hawaii north shorelines Kauai, Oahu, Big Island, Maui, Molokai up to 15 meter elevation (Hawaii State Civil Defense) Guam topo and bathymetric LIDAR(Guam Department of Homeland Security, Guam DPW)Saipan topo (CNMI EMO, CNMI CRMO, CNMI DPW) 2. Saipan completed. Guam to be completed in March. Hawaii products to start being delivered in late March. 3. Concern from military about raw LIDAR data. Corps will not distribute data, it will need to be released by customers.
  • LiDAR Data Resources People to contact Benton Ching USACE Fort Shafter "Ching, Benton Y POH" <Benton.Y.Ching@poh01.usace.army.mil> Henry B. Wolter USGS Geospatial Liaison, Hawaii and Pacific Basin Islands NSDI Partnership Office 677 Ala Moana Blvd Suite 415 Honolulu, Hawaii 96813 808-587-2409 808-282-8995(cell) hwolter@usgs.gov Craig Tasaka Office of Planning, GIS Program Phone: (808) 587-2895 Fax: (808) 587-2899 Email: Craig_tasaka@dbedt.hawaii.gov
  • Mahalo Matt Barbee SOEST University of Hawaii Matthew [mbarbee@hawaii.edu] Craig Clouet ESRI Honolulu Office 1357 Kapiolani Blvd Suite 1110 Honolulu, Hawaii 96814 (808) - 947-0993 cclouet@esri.com HIGICC