Validation of Aerial LiDAR Products For Transportation Applications

Transcription

1 Creating Value Delivering Solutions Validation of Aerial LiDAR Products For Transportation Applications Dr. Srini Dharmapuri, CP, PMP Michael Baker Jr., Inc. Lauren Little, PE Alaska DOT Public Facility

2 Agenda 1. Requirements 2. LiDAR Technology Background 3. Methodology 4. Deliverables

3 REQUIREMENTS

4 ADOT&PF Highway Mapping Data Requirement: 85 mile, 2-lane road corridor LiDAR data collect; Survey ground control; Orthoimagery; Civil3D Digital Terrain Model, certified TINs Breaklines developed through LiDARGrammetry Meeting: Engineering quality data Consistent, seamless data Repurposing the data for additional tasks Parks Hwy, Elliott Hwy, Dalton Hwy, AK

5 LiDAR TECHNOLOGY

6 LiDAR Selective Processing Approach From a single LiDAR Capture More efficient creation of deliverables More efficient utilization of project dollars One collection, many options, all customizable and project/budget driven

7 Project Workflow Ground Laser Processing Control Scanning QA/QC Deliverables

8 Why are LiDAR Technologies Exciting? Faster collection & mapping turnaround More cost-effective for appropriate projects Wider variety of deliverable options Data able to be used many times Technology on constant improvement arc

9 METHODOLOGY

10 Parks Highway Area of Interest ADOT Parks Highway Mapping-- Proj PROJ ECT AREA 10

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12 Ground Control Utilized to Constrain LiDAR Data Enhances Overall Accuracy Established via GPS RTK Centerline Profile Cross section profile

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14 Hydro-Flattening

15 LiDAR Data

16 Breaklines captured using LiDARGrammetry

17 TIN with Contours

18 LAS File Completeness Size of all the.las files (xxxxm X xxxxm) Proper file format and projected to the appropriate projection and Datum Proper vertical and horizontal units and Datum. Classification Class 1 unclassified; Class 2 ground; Class 7 low point/noise, overlap Extraction of statistics for each LAS files specifically for all the classes. Number of Points Min Elevation Max Elevation Mean Elevation Point Density

19 Data Void Validation Spatial distribution of geometrically usable points is expected to be uniform and free from clustering. A regular grid, with cell size equal to the design NPS*2 (Nominal Pulse spacing) will be laid over the data. At least 90% of the cells in the grid shall contain at least 1 LiDAR point (first Return). Data Density should be xx Points/Sq meter 1mX1m grid should have the requisite number of points Percentage = Number of grids meeting criteria in each LAS file /Total number of grids in each LAS file

20 Validation of Break Line BREAK LINE ACCEPTANCE CATEGORY PASS/FAIL Check for monotonicity of hydro breaklines. Verify that breakline vertices have z values equal to or less than the surrounding ground points. Vertices should not have a 0 or null elevation Culvert breaklines must snap to stream endpoints on both sides, and have the same elevation as the stream breakline at the snapping location. Automated Automated Automated Automated

21 Accuracy Road Centerline Data Value In feet Average dz Minimum dz Maximum dz Average Magnitude Root Mean Square Std Deviation ADOT Parks Highway Mapping 21

22 Observed Accuracy Dalton Highway Value In feet Average dz Minimum dz Maximum dz Average Magnitude Root Mean Square Std. Deviation 0.108

23 Observed Accuracy Parks Highway Number Easting Northing Known Z Laser Z Dz ARR DA DA DA DA PARKS PARKS PARKS PARKS Average Dz Minimum Dz Maximum Dz Average Magnitude Root Mean Square Standard Deviation

24 Project Amendment AOI #1 ADOT Parks Highway Mapping 24

25 Deliverables

26 Survey Deliverables Field Notes AutoCAD 2012.dwg: Survey Profiles, Crosssections, Control GPS Raw Data GPS Reports Survey Point Files TIN Certification Survey Summary ADOT Parks Highway Mapping 26

27 LiDAR Deliverables TINs (AutoCAD Civil 3D) Survey Data Drawing Tiles (AutoCAD) Documentation (LiDAR Control Report, other) LiDAR Point Cloud (.LAS files) Intensity Images (GeoTIFF files) Raw Point Files Items in red text above are delivered to client as of 10/16/12 ADOT Parks Highway Mapping 27

28 Intensity Imagery ADOT Parks Highway Mapping-- Proj

29 Contours with Intensity Imagery ADOT Parks Highway Mapping-- Proj

30 Contours (Example) ADOT Parks Highway Mapping 30

31 Validation of Aerial LiDAR Products For Transportation Applications Dr. Srini Dharmapuri CP, PMP LiDAR Scientist Michael Baker Jr., Inc. Beaver, PA