Center City in Philadelphia is a confluence of transportation, shopping, business and government agency activity, with several multilevel spaces within a few blocks. To effectively serve this area with its current geographic information system, the City of Philadelphia needed a complete view of the infrastructure of buildings, railways and surrounding areas inside and out for its Facilities Management, Public Safety, Space Planning and Real Property departments. Specifically, the city wanted to understand the building infrastructure with respect to 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 at least three buildings that connect to the defined pilot area; and in-building floor maps. To effectively analyze and manage this critical public safety infrastructure, the city needed access to accurate and comprehensive spatial data information that included varied datasets.
James L. Querry Jr., director of enterprise GIS, turned to PenBay Solutions, headquartered in Brunswick, Maine, a GIS firm that had handled many of the city’s enterprise GIS issues. “Jim wanted to model the city in 3D, and we have a particular expertise in modeling buildings in GIS,” explains Stu Rich, PenBay’s chief technology officer. “We began to explore ways to collect data from building interiors that could be represented in a model.”
Bringing Mobile Mapping IndoorsModeling building exteriors is a standard process that can be achieved using readily available tools, such as laser scanners. However, modeling the insides of buildings is more difficult due to the challenges involved in data collection. Traditionally, a tripod, laser and camera are set up to capture measurements and images at various locations. The equipment is then moved and set up multiple times until all perspectives of a room are captured. It’s an awkward and time-consuming process, and Rich believed there was a better way.
PenBay had recently done some demo work with the Trimble Indoor Mobile Mapping Solution (TIMMS), a new technology that integrates active and passive sensors on a mobile platform. The system accurately and quickly captures georeferenced spatial data with 360 degrees of coverage as the mobile system is moved through a building at walking speed. “The City of Philadelphia wanted 3D data capture with spherical imagery embedded,” Rich says. “The requirements of the project and the capabilities of the TIMMS platform lined up very well.”
In October 2009, the PenBay team arrived in Philadelphia with the TIMMS system. Within two days--just under 12 hours total--the team had gathered a comprehensive dataset of the interiors of all the major Center City buildings, including 3D spherical imagery. Collecting the required data using traditional methods would have taken weeks at a minimum.
Post processing was also much faster. With the TIMMS platform providing close to a 1:1 field-to-processing time ratio, the PenBay team was able to generate the required vector GIS 3D and 2D deliverables just two days after the data collection was complete. “The TIMMS platform is fast, and because the data comes off the system in real-world georeferenced coordinates, it allows us to incorporate those coordinates and the derivatives from those coordinates directly into the GIS infrastructure,” Rich explains.
A Better Sense of SpaceUsing the software provided with the TIMMS package, the PenBay team created 3D LiDAR point clouds that could be used as a beginning dimensional framework for the derivation of multiple datasets from architecture, engineering and construction planning to facilities asset inventories, emergency action planning and real property space plans. The team also generated a 3D video dataset for the entire captured area. These videos were presented in the deliverables as links; when clicked, the links opened a viewer in which the user could rotate the imagery 360 degrees in 3D or 2D to get a more complete view of the area--a capability that was of particular interest to the public safety community for planning and preparedness workflows as well as facilities managers for condition assessment and asset inventory.
PenBay also provided the city with a set of in-building floor maps of the captured area that provided a unique view of the indoor space with reference to the surrounding landscape. All of the deliverables were integrated into the city’s existing Esri Building Interior Space Data Model (BISDM), which is considered the best-practice approach to modeling buildings in GIS. “Being able to understand, for instance, how the subway lines align under the streets of Philadelphia and how the different access to spaces worked within the buildings under street level in the city all was possible because of how the 3D data were incorporated into the city’s larger geodatabase infrastructure,” Rich says.
In providing the city with this BISDM-compliant data, PenBay has allowed them to extend their existing GIS data for a holistic, 3D GIS view of the city’s busiest area to effectively address facility management, public safety, and real property issues. “Philadelphia is excited to be at the forefront of this tremendous advance in 3D in-building and subsurface spatial data collection,” says Querry. “Combined with other city initiatives, such as video surveillance and advanced enterprise GIS, we believe this will play a pivotal role in achieving the vision of making Philadelphia the safest large city in the nation.”
For PenBay, the project has opened new doors on the capabilities of modeling building interiors. The firm is currently involved in other similar initiatives in Washington, D.C., New York City and Boston, with additional projects on the horizon. “The TIMMS platform is particularly good at collecting data on infrastructure that is difficult to access or in which the existing data are unusable, as is often the case with older municipal infrastructure,” Rich says. “Being able to quickly gather georeferenced spatial data on building interiors fits nicely into our vision of incorporating the built environment into the GIS fabric that has evolved over the years.”