Maximizing ROI through Feature Automation of Lidar in the Digital Coast

Brian Mayfield, CP, GISP, SP, GIS

OverviewIn September of 2014, Atlantic won the 2014 MAPPS Geospatial Products and Services Excellence Award for utilizing Lidar data available in the public domain to extract 3D buildings for a group of government agencies in Northwestern TN. While their application was not coastal in nature, it does highlight trends and techniques that could easily be applied to solving coastal issues like resiliency and risk assessment of structures along the coast that may have vulnerabilities due to sea level rise and/or storm surge.

Process Overview1.Initial Assessment of Data (Existing Data Only)

2.Establish Algorithmic Lidar Classification Scheme

3.Manual QC and Algorithmic Classification Processes

4.Vector Building Extraction

5.Manual QC and Editing of Building Vectors

6.Final Quality Assurance and Editing of Product Datasets

USGS QL2 Sample ProjectMobile County, AL – 2014 Acquisition

1,229 mi2 Lidar ~ 4.5 ppsm Hydrolines to USGS Specifications Hydro-flattened DEM data 100 QA/QC survey checkpoint

Initial Assessment

Initial Assessment

Getting Started – Ground Class Only

The semi-automated procedureconsisted of various steps in orderto separate the buildings from thevegetation in addition to the otherpoints that are identified asunclassified points.

Run Building Classification Macro1. Classify points between 10

meters below ground and1.8 meters above groundto medium vegetation.

2. Classify first andintermediate echo pointsfrom unclassified to mediumvegetation to remove most ofthe top canopy and powerlines from the unclassifiedpoints - leaving the buildingsintact that normally have onlyecho.

Perform Limited Manual Cleanup

On Dauphin Island,most structures arebuilt on stilts and havedeck structures.

Notice the decks, stiltsand 1 chimney havebeen moved tounclassified (Class 1)

Vectorize Buildings

Atlantic has tested LP360,BAE GXP, Global Mapperand TerraSolid’s TerraScan –all Commercial Off The Shelf(COTS) software solutionswith building extractionroutines.

We found the best results forthis particular applicationcame from TerraScan.

Vectorize Buildings

Manual Editing:

The process does a great job classifying most of thebuildings, but does have difficulty with smaller buildingsand dense vegetation that are in close proximity to thebuildings.

Thus, manual editing is required to clean these features.

Model Check and Edits

Unedited Building

Model Check and Edits

Edited Building

Export Final Data

QUESTIONSBrian Mayfield, CP, GISP, SP, GISPresident & Chief Operating OfficerP: 256.971.991C: 703.340.4141E: kldenney@theatlgrp.com

Huntsville, AL (HQ)Washington, DCHouston, TXNashville, TN

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