Data Acquisition; Maintenance, and Dissemination

Transcription

1 Data Acquisition; Maintenance, and Dissemination Amar Nayegandhi, CP, CMS(RS), GISP Director of Remote Sensing Dewberry December 4, 2014

2 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.

3 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

4 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 photoncounting or photon-detecting LiDAR

5 Linear mode LiDAR + Can operate at over 500 KHz and altitudes of up to 15,000 ft for efficient wide area mapping. Trimble AX-80 RIEGL LMS-Q1560 Leica ALS 80 Optech Galaxy

6 Linear mode LiDAR + Private sector is fully capable of meeting all the requirements of 3DEP for wide area mapping.

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

8 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

9 Geiger mode LiDAR imaging + Uses significantly lower energy and can operate at much higher altitudes. + Each LiDAR footprint is an image array Geiger mode Image courtesy Harris Corp. Linear mode Geiger mode collects thousands of more measurements than Linear mode

10 Capability comparison Geiger mode LiDAR technology enables collection of very large areas, very quickly from high altitude Geiger Mode LiDAR Faster collection at reduced rate and higher resolution.

11 Collection Cost Geiger mode LiDAR reduces cost, especially for higher pulse densities Linear These efficiency gains keep costs down across a wider range of collection densities Geiger Mode Collection Density (points per square meter) Offers unprecedented densities 8+ ppm at affordable cost

12 TOPOBATHYMETRIC LIDAR

13 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.

14 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.

15 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

16 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 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 m m 600 m Nominal Laser water surface (@ 532 nm 4 m (deep); 2 m 2 m green) at nominal flying (shallow) 1.5 m 0.6 m height Point density (points per square meter) at nominal flying height Typical maximum water depth (measured as Secchi depth) System weight and power requirements 0.25 to 1 13 (topo); (bathy) 13 (topo); 1.2 (bathy) 6-10 (topo and bathy) lb / 100 A 374 lb / 100 A 176 lb / 30 A 55 lb / 10 A

17 Results from Riegl VQ820G in Sandy River, Oregon (2012) Study conducted by Dewberry in collaboration with Watershed Sciences, Inc 21 Powerpoint title goes here December 20, 2011 Digital Seamless Surface topo-bathy Model model

18 Elevation (m) Elevation (m) Elevation (m) Elevation (m) 1 Comparing with cross-sections LiDAR cross-sections are 2 m wide. LiDAR vs. GPS vertical accuracy: 18.4 cm RMSE (303 in-stream comparisons) Ground (GPS) X-section 3 m 6 Distance along transect (m) m Distance along transect (m) Powerpoint title goes here December 20, 2011 Distance along transect (m)

19 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, Flight Missions - ~6,700 flight lines - > 32,000 flightline miles (excluding reflies)

20 Topobathy data preliminary images 6 meters at deepest extent Ocean side bathymetry Dovers Beaches - NJ 6.5 meters at deepest extent

21 Sample profiles Hatteras Island, NC 7 meters at deepest extent 6 meters at deepest extent 11 meters at deepest extent, bathy extending nearly 800 meters offshore

22 Typical Barrier Island System (Assateague Island) 7 cm resolution RGB Imagery Back Bay Tidally influenced wetlands White water Upland Veg. Beach Ocean waves

23 Typical Barrier Island System (Assateague Island) Bare Earth Digital Elevation Model NIR

24 Typical Barrier Island System (Assateague Island) 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

25 Rich Inlet, Topsail, NC 0.5 m resolution DEM

26 BUILDING FOOTPRINTS FROM LIDAR

27 Building footprints + Automated routines to extract buildings with sparse (1-2 ppsm) data. + May not meet planimetric accuracy standards for low-density LiDAR

28 NEW ASPRS ACCURACY SPECIFICATIONS

29 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.

30 Common horizontal accuracy classes

31 Horizontal accuracy interpreted from ASPRS 1990 legacy standard Common Orthoimagery Pixel Sizes Associated Map Scale cm 1: cm 1: cm 1:200 5 cm 1: cm 1: cm 1:1, cm 1:2,400 ASPRS 1990 Accuracy Class Associated Horizontal Accuracy According to Legacy ASPRS 1990 Standard RMSE x and RMSE y RMSE x and RMSE y (cm) in terms of pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels pixels

32 Vertical accuracy / quality examples for digital elevation data

33 Vertical accuracy compared to ASPRS 1990 standard Vertical Accuracy Class RMSE z 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 cm cm cm cm cm cm cm cm cm

34 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.

35 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 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.

36 Thank you. Questions? Amar Nayegandhi Director of Remote Sensing Dewberry Ph: (office) Cell: