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