Data Acquisition; Maintenance, and Dissemination€¦ · In an economy where you are counting every dollar, it's good to know you can count on MAPPS. Overview + LiDAR acquisition

In an economy where you are counting every dollar,

it's good to know you can count on MAPPS.

Data Acquisition; Maintenance,

and Dissemination

Amar Nayegandhi, CP, CMS(RS), GISP

Director of Remote Sensing

Dewberry

December 4, 2014



About MAPPS + MAPPS is the only national association of private

sector firms in the surveying, spatial data and

geographic information systems field in the United

States.

- Regular member firms are engaged in LiDAR, surveying,

photogrammetry, satellite and airborne remote sensing,

aerial photography, hydrography, aerial and satellite

image processing, GPS and GIS data collection and

conversion services.

- Our associate members include firms that provide

products and services to our member firms, as well as

other firms world-wide.



Overview

+ LiDAR acquisition capabilities to support wide area mapping and 3DEP

- Linear-mode LiDAR

- Geiger-mode LiDAR

+ Seamless topobathymetric mapping in coastal and riverine environments

+ Derivative products – building footprints

+ Imagery acquisition enhancements

+ New ASPRS Accuracy Specifications



Linear vs. Geiger mode LiDAR

+ Traditional LiDAR is sometimes referred to as "linear mode,” where individual laser beams are used to measure range.

+ The term "Geiger mode” is used to describe a new breed of LiDAR, where the sensors do not observe individual laser beam returns, but rather the returns of individual photons.

+ Geiger mode LiDAR is also called photon-counting or photon-detecting LiDAR



Linear mode LiDAR

+ Can operate at over 500 KHz and

altitudes of up to 15,000 ft for

efficient wide area mapping.

RIEGL LMS-Q1560 Leica ALS 80 Optech Galaxy

Trimble AX-80



Linear mode LiDAR

+ Private sector is fully capable of meeting all

the requirements of 3DEP for wide area

mapping.



Geiger mode LiDAR + Has been used in DoD applications since 2000.

+ Commercial sector has been involved in processing of these data for many years.

+ System manufacturers are now developing Geiger mode LiDAR sensors, which will be available in 2015.

Geiger mode LiDAR imaging of the Grand Canyon (left), Kennedy Space Center (middle), NGA Headquarters building (right), acquired by ALIRT sensor and processed by Harris Corp.



How is Geiger Mode Different? Linear Mode Lidar Geiger Mode Lidar

• Range computed by measuring time of flight of a laser pulse

• Requires multiple photons for detection

• Single high energy, wide pulse

• Restricts resolving power

• Typically collect full waveform or discrete returns (1-4 for each pulse) using a single detector

• Relatively Slow scanning

• Lower Area of Coverage

• Range computed by measuring time of flight of a laser pulses

• Single photon detection

• Multiple low energy, narrow pulses

• Collect multiple discrete single photon returns from multiple narrow pulses

• Digitization at the detector

• Faster scanning due to compact multi-detector arrays



Geiger mode LiDAR imaging + Uses significantly lower energy and

can operate at much higher altitudes.

+ Each LiDAR “footprint” is an image array

Geiger mode collects thousands of more measurements than Linear mode

Image courtesy Harris Corp.

Linear mode

Geiger mode



Capability comparison

Geiger Mode LiDAR – Faster collection at reduced rate and higher resolution.

Geiger mode LiDAR technology enables collection of very large areas, very quickly

from high altitude



1 2 4 6 8 10 12 14 16 18 20 25 30 35 40 45 50 60 70 80 90 100

Offers unprecedented densities 8+ ppm at affordable cost

Geiger mode LiDAR reduces cost, especially

for higher pulse densities

These efficiency gains keep costs down across a wider range of collection densities

Co

llect

ion

Co

st

Geiger Mode

Linear

Collection Density (points per square meter)



TOPOBATHYMETRIC LIDAR



Airborne topobathymetric LiDAR + Airborne remote sensing technique

used to measure the height of the surface on land and underlying streams, rivers, lakes, bays, and shallow coastal waters in moderately clear water column conditions.

+ The depth range of bathy LiDAR systems is primarily limited by - water clarity (turbidity)

- bottom reflectivity

- type of LiDAR system being used.

+ Current bathy and topobathy LiDAR systems have depth performance of 1 to 3 times the Secchi depth.



Why topobathy LiDAR?

+ Complements acoustic (multi-beam sonar) technology

+ Airborne topobathy LiDAR is of high value in filling the “0 to 10 m” depth gap in coastal and riverine areas

+ Rapid survey of shallow water areas that are difficult, dangerous, or impossible to get using water borne methods

+ Ability to rapidly assess riverine and estuary environments: channel cross sections, biological habitat, riparian conditions

Image courtesy Watershed Sciences, Inc.



Commercial bathy and topobathy

sensors

+ Optech CZMIL

+ Leica AHAB

Hawkeye III

+ Leica AHAB

Chiroptera

+ RIEGL VQ-820-G /

VQ-880-G

Not intended to be an exhaustive list of all available sensors



Performance characteristics of

commercially available topobathy sensors

Sensors CZMIL Hawkeye III Chiroptera VQ-820-G

Manufacturer / Owner Optech Leica - AHAB Leica - AHAB Riegl

Maximum Pulse Repetition Frequency (kHz)

Land Topography 70 kHz 100 - 400 kHz 400 kHz 500 kHz

Shallow bathymetry 70 kHz 36 kHz 36 kHz 500 kHz

Deep bathymetry 10 kHz 10 kHz N/A N/A

Laser Energy per pulse at 532 nm (green)

3 mJ 3 mJ / 0.1 mJ 0.1 mJ 0.02 mJ

Nominal Flying Height 400 m 250 - 600 m 250 - 600 m 600 m

Nominal Laser footprint @ water surface (@ 532 nm green) at nominal flying

height

2 m 4 m (deep); 2 m

(shallow) 1.5 m 0.6 m

Point density (points per square meter) at nominal

flying height 0.25 to 1

13 (topo); 0.3 - 1.2 (bathy)

13 (topo); 1.2 (bathy)

6 - 10 (topo and bathy)

Typical maximum water depth (measured as Secchi

depth) 2.5 - 3 2 - 2.5 1.0 - 2.0 1.0

System weight and power requirements

850 lb / 100 A 374 lb / 100 A 176 lb / 30 A 55 lb / 10 A

Results from Riegl

VQ820G in Sandy River,

Oregon (2012)

21 | Powerpoint title goes here December 20, 2011

Digital Surface Model Seamless topo-bathy model

Study conducted by Dewberry in collaboration with Watershed Sciences, Inc

Comparing with cross-sections

22 | Powerpoint title goes here December 20, 2011

Distance along transect (m)



Ele

vati

on

(m)

Ele

vati

on

(m)

Ele

vati

on

(m)

Ele

vati

on

(m)

1

2 3 4 5

6

1 2 3 4 5

6

LiDAR cross-sections are 2 m wide. Ground (GPS) X-section

3 m

2 m

LiDAR vs. GPS vertical accuracy: 18.4 cm RMSE (303 in-stream comparisons)



Supplemental Sandy topobathy LiDAR and imagery task

for the NOAA NGS shoreline mapping program

+ Dewberry tasked as prime contractor under the NOAA CGSC II contract

+ Teammates – Quantum Spatial (LiDAR and Imagery), RC&A (Imagery Acquisition), Woolpert (Imagery Processing)

+ Project is currently underway (acquisition began Nov 21, 2013).

+ 3 aircrafts with topobathy LiDAR deployed and 2 aircrafts with DMC (imagery)

+ Acquisition completed July 27, 2014

- 304 Flight Missions

- ~6,700 flight lines

- > 32,000 flightline miles (excluding reflies)

6 meters at deepest extent

6.5 meters at deepest extent

Topobathy data preliminary images

Ocean side bathymetry Dovers Beaches - NJ



11 meters at deepest extent, bathy extending nearly 800 meters offshore

Sample profiles – Hatteras Island,

NC



7 cm resolution RGB Imagery

Ocean waves

White water

Beach

Upland Veg.

Tidally influenced wetlands

Back Bay

Typical Barrier Island System (Assateague Island)




Bare Earth Digital Elevation Model – NIR




Using NIR water surface data, Green submerged data and Dewberry’s custom refraction tool To create seamless topobathy Digital Elevation Model

bathymetry

bathymetry

NOT bathymetry



Rich Inlet, Topsail, NC

0.5 m resolution DEM



BUILDING FOOTPRINTS FROM

LIDAR



Building footprints

+ Automated routines to extract buildings

with sparse (1-2 ppsm) data.

+ May not meet planimetric accuracy

standards for low-density LiDAR



NEW ASPRS ACCURACY

SPECIFICATIONS



Purpose + Replaces the existing ASPRS Accuracy Standards for Large-Scale

Maps (1990), and the ASPRS Guidelines, Vertical Accuracy Reporting for LiDAR Data (2004) to better address current technologies.

+ This standard includes positional accuracy standards for - digital orthoimagery,

- digital planimetric data and

- digital elevation data.

+ Accuracy classes, based on RMSE values, have been revised and upgraded from the 1990 standard

+ The standard also includes additional accuracy measures for: - orthoimagery seam lines

- aerial triangulation accuracy

- LiDAR relative swath-to-swath accuracy,

- recommended minimum Nominal Pulse Density (NPD),

- horizontal accuracy of elevation data,

- delineation of low confidence areas for vertical data, and

- the required number and spatial distribution of check points based on project area.



Common horizontal accuracy

classes



Horizontal accuracy interpreted from ASPRS

1990 legacy standard

Common

Orthoimagery Pixel

Sizes

Associated Map

Scale

ASPRS 1990

Accuracy Class

Associated Horizontal Accuracy

According to Legacy ASPRS 1990

Standard

RMSEx and RMSEy

(cm)

RMSEx and RMSEy

in terms of pixels

0.625 cm 1:50

1 1.3 2-pixels

2 2.5 4-pixels

3 3.8 6-pixels

1.25 cm 1:100

1 2.5 2-pixels

2 5.0 4-pixels

3 7.5 6-pixels

2.5 cm 1:200

1 5.0 2-pixels

2 10.0 4-pixels

3 15.0 6-pixels

5 cm 1:400

1 10.0 2-pixels

2 20.0 4-pixels

3 30.0 6-pixels

7.5 cm 1:600

1 15.0 2-pixels

2 30.0 4-pixels

3 45.0 6-pixels

15 cm 1:1,200

1 30.0 2-pixels

2 60.0 4-pixels

3 90.0 6-pixels

30 cm 1:2,400

1 60.0 2-pixels

2 120.0 4-pixels

3 180.0 6-pixels



Vertical accuracy / quality examples for

digital elevation data



Vertical accuracy compared to

ASPRS 1990 standard

Vertical

Accuracy Class

RMSEz

Non-Vegetated

(cm)

Equivalent Class 1

contour interval per

ASPRS 1990 (cm)

Equivalent Class 2

contour interval per

ASPRS 1990 (cm)

Equivalent

contour interval

per NMAS (cm)

1-cm 1.0 3.0 1.5 3.29

2.5-cm 2.5 7.5 3.8 8.22

5-cm 5.0 15.0 7.5 16.45

10-cm 10.0 30.0 15.0 32.90

15-cm 15.0 45.0 22.5 49.35

20-cm 20.0 60.0 30.0 65.80

33.3-cm 33.3 99.9 50.0 109.55

66.7-cm 66.7 200.1 100.1 219.43

100-cm 100.0 300.0 150.0 328.98

333.3-cm 333.3 999.9 500.0 1096.49



3DEP/LiDAR • November 2013 National Academy of Public

Administration (NAPA) report “FEMA Flood

Mapping: Enhancing Coordination to Maximize

Performance” included the following

recommendation:

+ “The Office of Management and Budget should

use the 3DEP implementation plan for

nationwide elevation data collection to guide

the development of the President’s annual

budget request.”



Summary + Currently available linear-mode LiDAR technology is capable

of meeting all requirements of the 3D Elevation Program.

+ Geiger-mode LiDAR is a new technology that is more efficient for mapping wide areas at much higher densities.

- The private industry is developing multiple Geiger mode LiDARs, operational in 2015.

+ Seamless topobathy data for floodplain mapping is now feasible with new and improved topobathy systems (in relatively clear coastal and riverine conditions).

+ Satellite imagery is positioned to acquire very high-resolution imagery at reduced costs.

+ New ASPRS Accuracy specifications to be published in early 2015 better addresses current and future technologies.

+ MAPPS urges TMAC to endorse the NAPA recommendation that OMB use 3DEP.



Thank you. Questions?

Amar Nayegandhi Director of Remote Sensing Dewberry [email protected] Ph: 813 421 8642 (office) Cell: 727 967 5005

Documents

Data Acquisition; Maintenance, and Dissemination€¦ · In an economy where you are counting every dollar, it's good to know you can count on MAPPS. Overview + LiDAR acquisition