Fugro EarthData, Inc'

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Fugro EarthData, Inc.
What lidar data can do for you Maximizing the
return on investment from this robust source of
geospatial data South Carolina LiDAR Partnership
Workshop 8 April 2008 Harold Rempel
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Presentation Outline

• Lidar 101
• Principles of Lidar
• Sensor
• Aircraft
• Advantage and Disadvantages
• Lidar Accuracy
• Project Design Considerations
• Lidar Production Flow
• Overview
• Data Acquisition/Verification
• Pre-processing/Calibration
• Processing
• Quality Control Processes

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Presentation Outline

• 2008 South Carolina Project
• Deliverables Formats Specifications
• Project Design
• Aerial Acquisition - A Success Story
• Hydro-Breakline Generation
• Project Quality Measures
• The Many Uses of Lidar
• Lidar Applications
• Feasible Products with SC Dataset
• New and Future Services

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Lidar 101
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Lidar 101
P R I N C I P L E S

• What lidar is not
• All weather
• Some haze is manageable fog and clouds are not
• Target must be visible in the sensors EM range
• Able to see through trees
• LIDAR sees around trees, not through them. Fully
  closed canopies (rain forests) cannot be
  penetrated
• Light (or laser) assisted radar
• RADAR uses electro-magnetic (EM) energy in the
  radio range, LIDAR does not.

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Lidar 101
P R I N C I P L E S

• Operational principles
• A pulse of light is emitted and the precise time
  is recorded at t1
• The reflection of that pulse is detected and the
  precise time is recorded at t2
• Using the constant speed of light, the delay
  (t2-t1) can be converted into a slant range
  distance.
• range speed of light time
• Knowing the position and orientation of the
  sensor, the XYZ coordinate of the reflective
  surface can be computed.

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Lidar 101
P R I N C I P L E S
?
pivot
mirror
laser beam
target
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Lidar 101
P R I N C I P L E S
Signal Breakdown
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Lidar 101
S E N S O R

• Basic Sensor Components
• Laser Source
• Laser Detector
• Scanning mechanism controller
• Electronics for timing emissions reflections
• Airborne GPS (position, speed, direction)
• Inertial Measurement Unit (attitude)
• High Performance Computers
• High Capacity Data Recorders

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Lidar 101
AeroScan System
S E N S O R
Supporting electronics
Laser Detector
IMU Controller
Head Unit
Pulsing Laser
Removable Hard Drives
IMU
Scan Mirror Controller
Scan Motor
Operator controls
Scan Mirror (internal)
LIDAR System Controller
Power inverter
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Lidar 101
S E N S O R
ALS50-II (MPiA) System
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Lidar 101
S E N S O R

• ALS50-II (MPiA) Specifications
• Pulse rate up to 150 kHz
• 75º field of view
• Single mirror
• Max flight height 15,000 AMT
• Max 4 range and 4 intensity returns per pulse

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Lidar 101
A I R C R A F T

• Cessna 310
• Twin engine piston
• Maximum speed 210 kts
• Range 678 nm
• Service ceiling 21,300 ft
• Rate of climb 1,650 ft/min

• Cessna 335
• Twin engine piston
• Maximum speed 230 kts
• Range 928 nm
• Service ceiling 26,800 ft
• Rate of climb 1,650 ft/min

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Lidar 101
A D V A N T A G E S

• Aerial acquisition can be executed day or night.
• Lidar point cloud can be used for numerous
  applications
• Lidar is better able to map terrain in dense
  vegetation when compared to photogrammetry.

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Lidar 101
A D V A N T A G E S

• Digital elevation data created from lidar are
  considerably denser and less expensive than those
  collected by traditional methods.
• Lidar is not affected by shadows

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Lidar 101
A D V A N T A G E S
Lidar does not see through the trees, but
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Lidar 101
A D V A N T A G E S
Lidar does provide a better opportunity to
establish an accurate terrain surface
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Lidar 101
A D V A N T A G E S M U LTIPLE RETURN
S
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Lidar 101
A D V A N T A G E S SEE IN SHADOWS
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Lidar 101
D I S A D V A N T A G E S

• Lidar is not all-weather, target must be visible
  in the sensors EM range
• Slight haze is manageable, fog is not
• Lidar does not penetrate tree canopy but rather
  exploits gaps in the canopy
• Lidar ranges affected by extreme absorption or
  reflective properties of certain features
• Contours derived from lidar points alone are not
  aesthetically pleasing and are not
  hydro-corrected.

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Lidar 101
ACCURACY BASICS

• Instrument Accuracy impacted by
• ABGPS precision
• IMU precision
• Timing resolution
• Mechanical tolerances (temperature and pressure
  variations)
• Atmospheric distortions
• Data Accuracy impacted by
• Instrument performance
• Quality of project design (control, flight plan,
  sensor settings)
• Cleanliness of data ( of artifacts remaining in
  model)
• Quality Control procedures

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Lidar 101
ACCURACY BASICS

• Most common guidelines are derived from Appendix
  A of FEMAs Guidelines and Specifications for
  Flood Hazard Mapping Partners.
• In 2002 the National Digital Elevation Data
  Program established guidelines that specifically
  address Lidar data
• Fundamental vertical accuracy 95 confidence
  level 1.2 feet (36.3cm) in open terrain
• Consolidated vertical accuracy 1.6 feet (49.0cm)
  for all land cover classifications combined

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Lidar 101
ACCURACY L ANDCOVER
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Lidar 101
ACCURACY S A M PLEREPORT
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Lidar 101
ACCURACY S A M PLEREPORT
NDEP Guideline
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Lidar 101
ACCURACY S A M PLEREPORT
FEMA Guideline
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Lidar 101
PROJECT DESIGN FACTORS

• Factors to consider in lidar project design
• Project specifications nominal post spacing,
  deliverables, accuracy specifications, purpose of
  the data/project.
• Environmental conditions typical weather,
  smoke/haze
• Ground conditions snow, ground cover
• Terrain flat, urban, mountainous, coastal
• Tidal requirements low/high tide request
• Water bodies size, water levels

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Lidar 101
PROJECT DESIGN TERRAIN

• Terrain is one of the most significant factors
• Tidal areas may require significant coordination
  and some luck
• Heavy vegetation and urban areas exponentially
  increases filtering time over that of flat, open
  areas
• Mountainous area with drastic elevation changes
  have a unique set of issues

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Lidar Shadowing
Lidar 101
PROJECT DESIGN TERRAIN
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Lidar 101
Range Gate Shutout
PROJECT DESIGN TERRAIN
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Lidar 101
PROJECT DESIGN TERRAIN
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Lidar 101
PROJECT DESIGN GPSSTATIONS
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Lidar Production Flow
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Lidar Production Flow
OVERVIEW
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Lidar Production Flow
ACQUISITION VERIFICATION

• Inputs to aerial data include
• ABGPS
• IMU (aircraft orientation)
• GPS base station information (tied to survey
  network)

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Lidar Production Flow
ACQUISITION VERIFICATION

• Output from aerial acquisition
• Raw data
• Processed ABGPS data
• Processed IMU data
• Processed Base station data
• Data QC of the raw data occurs
• On site with the sensor operator
• At the production facility in the Geopositioning
  Dept.

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Lidar Production Flow
CALIBRATION CHECK

• Phase involves the processing of raw lidar, IMU,
  and ABGPS data into xyz points.
• Overlap areas between lines are viewed in a
  differencing image to check for distortion or
  anomalies in the data caused by systematic errors
• Results are compared against the ground survey to
  ensure that the lidar is within specifications

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Lidar Production Flow
PREPROCESSING

• If a deliverable, lidar intensity images are
  produced before auto-filtering by taking the
  lidar point cloud and determining the best post
  spacing-to-pixel resolution match.

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Lidar Production Flow
PREPROCESSING

• Data is then auto-filtered and prepared for
  production.
• Auto-filters are based on a library of macros
  that can be tailored to a project areas unique
  terrain and land cover type.
• This step can classify 90-95 of the artifacts in
  the lidar points cloud.
• Great care must be taken on a large-scale project
  that contains a variety of terrain and land cover
  types.

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Lidar Production Flow
PROCESSING PRODUCTS

• During the processing phase, various lidar
  products are produced including (but not limited
  to)
• Bare earth tiles
• Reflective surface (first return) files
• Digital Elevation Models (gridded DEM)

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Lidar Production Flow
PROCESSING M ANUAL FILTER

• The remaining 5-10 of the artifacts in the lidar
  must be removed via manual interaction.
• Technicians view the data in profile and with
  surfacing tools to identify and classify
  remaining artifacts.
• The use of ancillary data (such as recent
  imagery) can enhance this process.
• A strong peer-review and final QC process is
  critical to this step.

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Lidar Production Flow
PROCESSING M ANUAL FILTER
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Lidar Production Flow
PROCESSING M ANUAL FILTER
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Lidar Production Flow
PROCESSING M ANUAL FILTER

• Field Intelligence case example
• Strange mounds found in data that technicians
  could not see in ancillary imagery.
• Could not decide if mounds were a valid ground
  features.
• Field trip to project location resulted in
  immediate improvement and uniformity of the
  manual processing.

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Lidar Production Flow
Q U A LITY C O NTROL

• Typical Quality Control Measures
• Aerial Acquisition
• Review of flight logs
• As flown GPS epochs checked against flight plan
• Visual QC of data coverage
• Check of Airborne GPS/IMU processing against
  specs
• Preprocessing/Calibration
• Check for pitch, roll, yaw anomalies
• Check for data coverage
• Check against ground survey points
• Processing/Packaging
• Sampling of data to ensure consistency of
  filtering
• Check on format and content of deliveries

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Results

• A successful lidar project has
• Solid project design
• Proven work flow
• Quality control throughout the processes
• Strong project management
• Stakeholder agreement on project purpose scope
• Without the above components stakeholders may not
  get what they bargained for in the end

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Results
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2008 South Carolina Project
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2008 South Carolina Project

• 2008 South Carolina Project
• Deliverables Formats Specifications
• Project Design
• Aerial Acquisition - A Success Story
• Hydro-Breakline Generation
• Project Quality Measures

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2008 South Carolina Project
DELIVERABLES _ O V E R V I E W

• Shape files delineating as-flown flight lines
• Lidar point cloud _at_ 1.4 meter nominal spacing
• LAS format
• Classifications
• Class 1 Unclassified (non-ground points)
• Class 2 Ground (bare earth, extra points)
• Class 8 Model Key Point (thinned bare earth)
• Class 9 Water (as classified by
  hydro-breaklines)
• Class 12 Overlap Points (points in overlap area
  between lines)
• ESRI multi-point feature class in Geodatabase
  format
• Hydro-breaklines (feature class in Geodatabase
  format

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2008 South Carolina Project
DELIVERABLES _ O V E R V I E W

• ESRI terrain feature dataset
• Lidar intensity images in GeoTIFF format
• FGDC-compliant metadata (project and tile level)
• Lidar system data report
• Accuracy Assessment Report by County

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2008 South Carolina Project
DELIVERABLES _ SPECS

• Lidar data acceptance criteria
• Accuracy in accordance with NSSDA and FEMA
  guidelines
• Assumes that all errors follow a normal
  distribution
• RMSEz for all land cover categories combined lt
  18.5 cm
• RMSEr lt 1 meter (horizontal accuracy)
• 90 of artifacts and 95 of outliers removed
• No significant gaps in data
• Tiles edge-matched
• Data clipped to boundary of project full tiles
  between county boundaries delivered

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2008 South Carolina Project
DELIVERABLES _ SPECS

• Breakline acceptance criteria
• Reflect all rivers, streams, lakes, ponds,
  resevoirs.
• Continuous flow
• Vertical consistency no vertices with 0
  elevation or excessive values
• Breaklines should not intersect unless at same
  elevation
• Single-line streams defined as water features lt
  50 ft in width
• Double-lined streams defined as water features lt
  50 ft in width

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2008 South Carolina Project
P ROJECTDESIGN _ F L I G H T

• Considerations for this project area included
• Project Schedule
• Resource allocation
• Risks
• Project Specifications
• Flight and Control Design
• Environmental and contractual flight window

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2008 South Carolina Project
P ROJECTDESIGN _ F L I G H T

• 10,194 sq. miles
• 20,757 total line miles
• 49- day acquisition window
• Ideal acquisition window in SC is 60 days

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2008 South Carolina Project
P ROJECTDESIGN _ S U R V E Y

• 212 ground survey points
• 8 airport GPS base stations
• Close coordination with surveyor required
• Not to be confused with independent survey check
  points

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2008 South Carolina Project
P ROJECTDESIGN _ P R O D U C T I O N

• 12,036 tiles
• Tiles based on statewide 5,000x 5,000 grid
• Final products to be edge-matched for
  consistency
• Delivery by Lot with 2 counties per Lot

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2008 South Carolina Project
P ROJECTDESIGN _ A S F L O W N

• As-flown trajectory files
• Verifies planned vs. actual
• Includes turns
• Turn line miles 3,840

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2008 South Carolina Project
AERIALACQUISITION _ SUCCES
S

• An Acquisition Success Story
• 2 crews per aircraft mobilized, effectively
  doubling flight time
• Ground survey crews established base stations and
  collected survey control well ahead of the
  aircraft.
• Entire project area of 16 counties collected
  within 14 days of flying after contractual notice
  to proceed.
• To date, 100 of the flight data has passed
  through the Geopositioning group QC.

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2008 South Carolina Project
HYDROBREAKLINES

• Breaklines are required to accurately define
  stream banks to facilitate HH engineering and
  modeling
• The synthetic breakline approach proved to be
  efficient and cost effective
• The hydro breaklines produced in this manner are
  NOT recommended for use in generating contours

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2008 South Carolina Project
HYDROBREAKLINES
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2008 South Carolina Project
HYDROBREAKLINES
TIN SURFACE WITH BREAKLINES
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2008 South Carolina Project
QU ALITYMEASURES

• Aerial Acquisition
• Approval of project boundary and flight design by
  PM and stakeholders
• Hand-off of data to Geopositioning group as soon
  as each lift is flown
• Review of daily flight reports
• Timely processing of ABGPS/IMU and check against
  specifications
• Processing
• Large boresight team utilized to identify
  problems immediately
• Extensive ground survey allowing flexibility in
  processing and stronger checks
• Peer-review process throughout production steps
• Data review and sampling is threaded into the
  entire production flow and not just at the end of
  the process.

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2008 South Carolina Project
QU ALITYMEASURES

• Specific QC Measures
• Data evaluation for collection errors
• Excessive noise
• Gaps
• Steps
• Hillshade checks for artifact review
  (filtering)
• Peer review independent review of every tiles
• Tile/Block QC lead technician reviews all
  blocks of tiles for consistency in filtering and
  edge-matching
• Final delivery QC format and coverage checks
• Dewberry Davis
• Review data delivered to ensure compliance with
  specifications
• Independent field survey checks and accuracy
  reports

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The Many Uses of Lidar

• The Many Uses of Lidar
• Current Applications
• Future Applications
• Feasible Products with SC Dataset
• New and Future Services

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The Many Uses of Lidar

• Lidar data can be utilized by numerous
  disciplines in private, federal, state and local
  communities
• A statewide lidar project benefits a multitude of
  users at the private, federal, state, and local
  levels.
• Applications include (to name a few)
• Disaster response
• 3D Modeling
• Line of sight analysis
• Flood plain modeling
• Volume analysis
• Transportation mapping
• Orthophoto rectification
• Land cover mapping
• Contour Generation

• Forestry
• Archeology
• Bathymetry
• Environmental Monitoring
• Military Applications
• Shoreline Management
• Mining
• Gas Oil Exploration

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The Many Uses of Lidar

• Applications are only limited by imagination

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The Many Uses of Lidar
DISASTERRESPONSE
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The Many Uses of Lidar
SUPPORTCONTOURS
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The Many Uses of Lidar
3 D MODELING
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The Many Uses of Lidar
AVIATION OBSTRUCTION ANALY
SIS
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The Many Uses of Lidar
CITYMODELS
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The Many Uses of Lidar
VIEWSHED ANALYSIS
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The Many Uses of Lidar
POWERLINEINSPECTION
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The Many Uses of Lidar
POWERLINEINSPECTION
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The Many Uses of Lidar
TRANSPORTATION MAPPING
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The Many Uses of Lidar
VOLUMEANALYSIS
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The Many Uses of Lidar
TREECANOPY HEIGHTS
Courtesy NCFMP Duke University - Tyler Bax and
Joseph Sexton
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The Many Uses of Lidar
CUSTOMIZATION OFDATA

• Custom-scaled DEMs for coastal hydrology
  applications

Courtesy NCFMP Duke University Ryan OBanion
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The Many Uses of Lidar
ENDANGERED SPECIES

• Reintroduction sites for federally endangered
  species of butterfly

Courtesy NCFMP Duke University Becky Bartel
and Joseph Sexton
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The Many Uses of Lidar
ELEVATIONMAPS
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The Many Uses of Lidar
WHATCANSC DATASUPPORT

• Applications that can be directly derived from
  the 2008 SC Lidar dataset
• Disaster response
• 3D Modeling
• Line of sight analysis
• Flood plain modeling
• Volume analysis
• Transportation mapping
• Orthophoto rectification
• Land cover mapping
• Contour Generation
• Contour generation from lidar points typically
  requires the addition of accurate breaklines to
  support certain contour intervals and accuracy
  specifications.

• Forestry
• Archeology
• Bathymetry
• Environmental Monitoring
• Military Applications
• Shoreline Management
• Mining
• Gas Oil Exploration

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The Many Uses of Lidar
NEWFUTURE

• Advancements in technology directly benefit the
  customer.
• Expanded sensor capabilities, process
  improvements, and new partnerships are directly
  benefiting the customer.
• Examples of new services/partnerships include
• Lidargrammetry
• FLI-MAP
• Urban Reality

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The Many Uses of Lidar
NEWFUTURE LIDARGRAMMETRY

• Up until recently, intensity data have been
  primarily used to create ancillary information
  such as black-and-white supporting images, or to
  improve automated-filtering routines and
  sensor-calibration.
• With the advent of sensors capable of scan rates
  above 100kHz, it is now feasible to generate
  intensity stereo pairs with resolution better
  than 1-meter.
• With this capability, vendors can integrate a
  photogrammetric workflow with highly accurate
  lidar data, allowing for the stereo-collection of
  features without imagery.

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The Many Uses of Lidar
NEWFUTURE LIDARGRAMMETRY

• Pros
• Lidargrammetry workflow can exploit current skill
  sets and equipment (resources) with minimal
  training.
• Has been shown to reduce manual editing time of
  lidar
• Stereo models can be larger, covering greater
  areas
• Rapid delineation of breaklines/planimetric
  features
• Cons
• Water features may be partially missing due to
  reflectivity
• Defining clean edges of planimetric features such
  as buildings can be difficult due to pixel size
• Vegetation can obscure features

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The Many Uses of Lidar
NEWFUTURE LIDARGRAMMETRY
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The Many Uses of Lidar
NEWFUTURE LIDARGRAMMETRY
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The Many Uses of Lidar
NEWFUTURE LIDARGRAMMETRY
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The Many Uses of Lidar
NEWFUTURE LIDARGRAMMETRY
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FLI-MAP
NEWFUTURE SERVICES
FLI-MAP lidar mapping system

• Designed primarily for corridor mapping

• Helicopter platform
• High-density, high-accuracy data set
• Simultaneous lidar and imagery data capture
• Up to 250kHz pulse rate
• 70 points/m2 at 100m flying height and 20 m/s
  speed
• Laser ranging accuracy 1 cm
• 60 laser swath angle, 3 look angles (forward,
  nadir, backward)
• Image sources line scan imagery, frame
  photography, and video

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FLI-MAP
NEWFUTURE SERVICES
How it Works
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FLI-MAP
NEWFUTURE SERVICES
3D visualization of colorized lidar points from
FLI-MAP acquisition
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FLI-MAP
NEWFUTURE SERVICES

• FLI-MAP Applications
• Corridor Mapping Applications
• Transmission lines
• Railways
• Highways
• Pipelines
• Levees
• Area Mapping Applications
• Rail yards
• Oil Gas assets

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FLI-MAP
NEWFUTURE SERVICES
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Urban Reality
NEWFUTURE SERVICES

• Terrestrial 3D laser scanning system
• Screen renderings 3D data of the Fugro EarthData
  facility collected by Urban Reality.
• Total data set is over 3.5 million points.
• Data was collected from a van mounted system,
  driving 20 MPH.
• Total data collection and processing lt 1 hour.

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Questions