Lidar Unlocks Subterranean Philadelphia

A 962Kb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE

Center City in Philadelphia is a confluence of transportation, shopping, business and government agency activity, with several multi-level spaces (including underground) within a few blocks. The fifth biggest region in the nation, Center City also boasts the third-largest downtown population. The City of Philadelphia is committed to encouraging business and real estate development in the area and has embarked on an innovative project to build up the area while at the same time making certain the downtown remains ready for business every day.

To effectively serve the city, including this bustling area, City staff relies on their GIS, which is based on Esri ArcGIS. Like most traditional GIS installations however, theirs did not include data for the insides of the Center City buildings or the vast infrastructure under the streets. In order to maintain and grow the City effectively, staff need a complete view of the infrastructure–both inside and out–of buildings, railways and surrounding areas for their facilities management, public safety, space planning and real property departments.

PenBay Solutions, an Esri partner headquartered in Brunswick, Maine, was contracted by the City to provide facility management mapping services for a pilot project aimed at testing the effectiveness of a total 3D GIS solution. This service included interior data collection utilizing an innovative robotic platform employing 3D LiDAR and spherical imagery technology, coupled with advanced global positioning systems (GPS) and inertial measurement unit (IMU) systems to develop vector floor map data for specific areas of interest. The specific platform used was the Trimble TIMMS system. The focus of this effort was to develop spatially accurate floor map data of the underground infrastructure that connects several notable buildings along Market Street in Philadelphia.

PenBay provided this data to the City in a building information system data model (BISDM)-compliant data set, This gives the City the capability to more easily extend their existing GIS data for a holistic, 3D GIS view of the City’s busiest area when needed. Providing data in a structured format allows City staff to address issues more effectively going forward.

One cloud–many uses
This pilot project includes several innovative deliverables.

First is a 3D LiDAR point cloud that will be dimensionally accurate in real-world coordinates. This deliverable will be used as a beginning dimensional framework for the derivation of multiple data sets from architecture, engineering, and construction planning to facilities asset inventories, emergency action planning, and real property space plans.

Also provided to the City is a set of spherical images for the entire captured area. This deliverable should be of particular interest to the public safety community for planning and preparedness workflows. This deliverable also provides assistance to facilities managers in condition assessment and asset inventory.

Last includes a set of in-building floor maps of the captured area. This deliverable should be of interest to real property and space planners, as well as public safety. This provides the City a unique view of their indoor space with reference to the surrounding landscape.

Understanding the inside to make sense of outside space
The City’s challenge was to understand their building infrastructure better. They are interested in seeing the relationship between: pedestrian concourses with platforms, corridors, stair locations, and ramps; ingress and egress points; emergency access and air vent facilities; connections between levels. Partial interiors of a minimum of 3 buildings that connect to the defined pilot area; and in-building floor maps. To effectively analyze and manage this critical public infrastructure they need access to accurate and comprehensive spatial data information, including varied datasets that include data about space like rooms and how they are being used; asset data, such as fire extinguishers and other components found within the rooms; and spherical images that are collected to guide anyone who needs to access the space, such as public safety officials, so they can get a real sense of what a space looks like.

In order to effectively plan and execute this project, a site assessment and requirements validation was conducted at the client site. The goals of this activity were to validate deliverable requirements and define data collection specifications; identify project logistical support requirements, discuss and validate project staging, access, and scheduling dependencies and visually inspect project areas of interest.

Upon completion of the site visit, PenBay staff, in conjunction with the client, developed a detailed list of priorities, points of contact, access dependencies, and geographic proximity that allowed for the creation of a project plan and schedule to capture the data. The decision was made to operate one two-staff crew onsite under the control of the project manager. This plan optimized the use of PenBay and client staff so that there would be a minimal impact on building occupants, and client resources.

Collecting data during business hours
Once the dates for the survey visit were determined–the survey itself took place in the fall of 2010–PenBay started the logistics necessary to mobilize the equipment and staff needed to execute the data collection phase of the project. Upon arrival at the client site, the survey team closely coordinated their collection activities with the client. Since data collection happened mostly at night in order to keep with Center City’s mission of not impacting the community, security escorts were provided by the City for safety as well as to provide unencumbered access to all areas, such as the subway system and secure buildings. Staff took only 20 hours to collect all the data necessary for the pilot project.

After completion of the data collection, PenBay initiated the data processing workflows that took the raw LiDAR point cloud data and spherical imagery captured in the field and created several useful data products including CAD (AutoCAD) and 3D BIM (Revit) files of the area of interest and of course, the primary deliverable of an ArcGIS geodatabase to make the files easily accessible to the City staff over the web.

Through this pilot, PenBay was able to demonstrate how critical deliverables can be created to support the City facilities management initiative, including: creating space definitions defining where boundaries such as hallways and rooms beginning and end within the City GIS; capturing floor plan data to represent interior space and structure accurately; and performing facility surveys quickly, safely and cost effectively. This survey provided the client with a clear and accurate view of how their underground infrastructure links to its above ground buildings and roads.

Built for the future
In total, PenBay collected 340,000 square feet of designated infrastructure. Using a combination of GIS and robotics, PenBay was able to measure pertinent space in a fraction of the time it takes with traditional collection methods. Since these facilities are complex and have a high volume of pedestrian traffic, minimal survey time and disruption was a critical factor that PenBay was able to provide with this highly efficient spatial data collection method. The floor maps, or georeferenced space plans, created by PenBay’s in-building data collection methodology were provided to give the City an accurate understanding of their current building space and floor materials within them.

With their city agency experience, PenBay provided the City with a GIS solution that employs a spatial data collection technology to collect a host of information in one pass. The result is a standards-compliant geodatabase useful to multiple city agencies as an extension of their existing GIS.

PenBay helped the City collect and develop GIS-ready data sets in the form of 2D and 3D map documents that should be of particular interest to several City service functions including Public Safety, Evacuation Planning, Facility Management and Lease Management to make better informed decisions in the future. The City now has a model for a standards-compliant geodatabase that provides a holistic GIS view of its subterranean space and assets.

Stuart Rich is Chief Technology Officer at PenBay with more than 15 years experience developing database applications and geographic information systems (GIS) for government and commercial organizations across the US and internationally. He has several years of extensive GIS experience, with an expertise in ESRI technology and a focus on project management, data analysis and modeling, business process analysis and workflow methodology design.

A 962Kb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE

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