Center City Philadelphia is the third most populous downtown district in the United States, trailing only downtown New York and Chicago. It's a confluence of transportation, shopping, business, and government agency activity, with several multilevel spaces within a few blocks. It's also the downtown hub and subway station for the Southeastern Pennsylvania Transportation Authority; the Pennsylvania Convention Center and its main hotel are connected to it.
In early 2010, city officials realized that to serve this area effectively with the city's current GIS, they needed a more complete view of buildings, railways, and surrounding areas – inside and out – for the facilities management, public safety, space planning, and real property departments. They needed more effective data management.
Center City had evolved over a number of additions and renovations during more than 25 years. The challenge for the GIS professionals of Penbay Solutions (an Esri Partner Network Gold member) was to fully understand the existing building infrastructure with respect to several key areas including 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. This required Penbay to collect many different datasets for the final GIS database.
"There are a number of different interests that come together in Center City Philadelphia," said Stuart Rich, chief technology officer of Penbay. "One of the major challenges in getting facilities data into a GIS database is you often have highly variable and less clearly defined inputs than you would like, particularly when there are a number of different contractors delivering different pieces of a total project. One of the business drivers was to have a useful data management set at the back-end. That was why that location was selected as the pilot to show why that data was valuable to the community."
Penbay began work in the fall of 2010. To effectively capture Center City, a 3D LiDAR point cloud that is dimensionally accurate in real-world coordinates was created using Trimble scanning devices. This point cloud was used as a beginning dimensional framework for the derivation of multiple datasets from AEC planning to facilities asset inventories, emergency planning, and real property plans.
A 3D video dataset was created for the captured area so that public safety officials could use it for planning and preparedness work. This deliverable also provided assistance to facilities managers in condition and asset inventory. .LAS files from the 3D point cloud were used to create a 3D architectural skeleton of the pilot area in Autodesk Revit. Once the Revit models were complete, they were exported through AutoCAD files into an Esri geodatabase. The final GIS deliverable provided the city with a view of its indoor space in reference to the surrounding landscape.
"Native LiDAR files have limited value to customers because they're huge, hard to use, and have no real intelligence about who owns the space and how it's being used in them," Rich said. "We took the .LAS files, created parmetric Revit BIM models from them, and then exported them through CAD to GIS. As long as we went through CAD, it went fine."
The final Building Information Systems Data Model (BISDM) was delivered to the city of Philadelphia in a geodatabase and Penbay also delivered several service definitions so that Philadelphia could publish it in ArcGIS server and consume it in ArcScene or ArcGlobe.
Providing Philadelphia with this BISDM-compliant data has allowed them to demonstrate the feasibility of extending their existing GIS data for a holistic, 3D GIS view of the city's busiest area to effectively address its 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," said James Querry, director of enterprise GIS for the city of Philadelphia. "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."
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