semi autimated extraction of 3d buildings for the city of boulder … · 2015. 8. 17. · terrascan...

“Sanborn” and “Sanborn Map” are Trademarks owned by The Sanborn Library, LLC and used under license by The Sanborn Map Company, Inc.

Semi-Automated Extraction of 3D

Buildings for the City of Boulder

• Company Overview

• LiDAR

‒ Collection

‒ Accuracy

‒ Classification

‒ Point Density

• City of Boulder Case Study

‒ Workflow

‒ Samples

• Summary

Overview

Sanborn Office Headquarters

On-Site Locations

Sacramento, CA

Colorado Springs, CO Charlotte, NC

Pelham, NY

Ft. Collins, CO

170 Employees

Four Offices Nationwide

Sanborn Office Locations

Full suite of capabilities

Sanborn Overview

• Started utilizing LiDAR in the late 1998

• Developed first commercial product for hydro flattening in 2004

• Sanborn has completed over 200,000 square miles of mapping within

the State of California over the past five years

• Have completed multiple LiDAR projects within difficult terrain

LiDAR at Sanborn

We have great customers!

National Research Council of the National Academies

• “LiDAR produces very-high-resolution three-dimensional point clouds in a

wide variety of land cover types at accuracies equivalent to or better than

photogrammetry…”

• “LiDAR can be acquired day or night, in cloudy conditions, leaf on or leaf

off and no sun angle limitation…”

• “LiDAR is able to penetrate to the bare earth in vegetated area better than

either IFSAR or photogrammetry…”

• “LiDAR data processing and feature extraction can be incorporated

seamlessly into the production environment designed for

photogrammetry…”

LiDAR Accuracy

USGS 30 Meter DEM vs. LiDAR DEM

LiDAR Accuracy

• ASPRS Standard LiDAR Point Classes

• Tolerance for Misclassification

• QL-0 and QL-1: 0.5%

• QL-2: 1%

• QL-3: 2%

Classification Levels

Classification Levels

All Points

Point Cloud Classification Examples

Ground


Ground and Vegetation


Ground and Buildings


• Background:

– City of Boulder had collected LiDAR in 2014

– Data had been classified manually

• Goal:

To estimate the accurate solar potential for buildings’ rooftops in a

cost-effective manner

Case Study: Solar Potential Estimation for the City of Boulder

• Software: TerraScan

• Process:

1. Auto-filter the LiDAR point cloud in the ground, building and

vegetation classes.

2. Macros are used to auto-filter the data.

3. The auto-filter macro steps have to be modified depending on the

land-cover and type of terrain.

Automated Building Extraction Workflow

Automated 2D Building Footprint Extraction

• Software: LP360 for ArcGIS

• Process:

1. Ingest the data in LP360 for ArcGIS software.

2. Use the points in the building class to derive the 2D building

polygons.

3. The settings to derive the vectors have to be modified depending

on the land-cover and type of terrain.


From LP-360

Automated 2D Building Footprint Extraction

Automated 2D Building Extraction

From LP-360

• Software: TerraScan

• Process:

1. Import the data into TerraScan and use the 2D footprints to

create bounding boxes for extracting 3D wireframes

2. Export as dae files


Automated 3D Building Wireframe Extraction

From TerraScan

• Software: FME

• Process:

– The exported dae files from the previous step are converted to

geodatabase (or other formats) using FME


• Software: ESRI CityEngine/ArcScene

• Process:

– The extracted wire-frames are imported into ESRI CityEngine or

ArcScene for further consumption

– Over 40,000 buildings extracted

– Success rates above 90%


Automated 3D Building Wireframe Extraction

Visualized in ArcScene Visualized in ESRI CityEngine

Step 1

• Auto-filter the LiDAR point cloud in the ground, building and vegetation classes. TerraScan macros are used to auto-filter the data.

• The auto-filter macro steps have to be modified depending on the land-cover and type of terrain.

Step 2

• Ingest the data in LP-360 for ArcGIS software. Use the points in the building class to derive the 2D building polygons.

• The settings to derive the vectors have to be modified depending on the land-cover and type of terrain.

Step 3

• Import the data into TerraScan and use the 2D footprints to create bounding boxes for extracting 3D wireframes

• The exported dae files are converted to geodatabase (or other formats) using FME

Automated Building Extraction Workflow: Review

• Allows users to search for available datasets by geographic

boundaries or location search

• Users can filter the results by file formats, source agency, vintage, etc.

• Preview feature allows the users to visualize the dataset in the LiDAR

web viewer

LiDAR Data Dissemination: GeoData Cache

• Washington DC OCTO

• Sanborn acquired and processed a wide range of high-resolution

imagery products simultaneously in 2015, including:

– 3-inch resolution orthoimagery

– 4-inch resolution oblique imagery

– LiDAR data

• Up to 150 points/sq m (ppm)

High Density Collection

High Density Collection

Washington National Cathedral

Lincoln Memorial

High Density LiDAR Collection

Thomas Park


The Washington Monument


100 ppm 20 ppm 4 ppm

LiDAR Point Density

Sanborn

Indoor Mapping Solution (SPIN)

http://www.sanborn.com/services/SPIN-Indoor-Mapping

• Classified LiDAR can be used for automated extraction of 3D

wireframes, expediting an otherwise time-consuming stereo

compilation process

• The automated workflow is easy to use, scalable and can achieve

success rates above 90% with dense, accurate LiDAR point clouds.

• The workflow is designed to minimize manual editing and represents

considerable improvements in productivity and cost savings.

• High density LiDAR collection can offer new opportunities for

automated 3D building creation, not possible earlier.

• Watch this space!

Summary

Sanborn Mobile Mapping

Questions?

semi autimated extraction of 3d buildings for the city of boulder … · 2015. 8. 17. · terrascan...

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