The Need for Comprehensive 3D City Models (Part 1)


At PenBay, we have spent a significant amount of time over the past several years working on ways to model the insides of buildings in GIS. I have written repeatedly about the subject and it is an area that continues to fascinate me. On my recent trip to Vancouver to speak at the GeoWeb 2009 conference, however, I was inspired by Thomas Kolbe’s work on CityGML to think more about collections of buildings and how they work together in an urban environment. As we move to this city and regional scale, the level of granularity at which we model our buildings has big implications on scalability, performance, and the tool sets that we use for visualization and analysis.  For the purposes of our discussion here, let's define a “City” is a reasonably large collection of buildings in a condensed area. This city might be a traditional municipality like Philadelphia or Chicago, it might be a military city like Langley Air Force Base, or it might be a college campus like Boston University.

Communities of Interest

There are many different communities of interest that need to develop a more comprehensive understanding of the urban and suburban environment in three and four dimensions with the fourth dimension being time. I have tried to identify some of the more common communities of interest along with their specific concerns below.

Landscape Planners

Landscape planners and urban designers are some of the “GeoDesigners” that Jack described in his plenary presentation at the ESRI UC this summer.  These are the folks that are responsible for designing the urban and suburban environments of the future. Some of these communities like the University Planning Office at Harvard or MIT are thinking about the futures of their campus environments 50 and 75 years out. Landscape planners and urban designers need to be able to visualize the impact of newly proposed projects on the city environment. They need to be able to understand how proposed projects will affect the skyline, how they will affect available sunlight in the surrounding area, how they will impact the local transportation infrastructure, how they will impact utility infrastructure, and how they will affect the need for public services such as schools and public safety. Landscape planners are often interested in land use and permitting issues. They will often influence land-use entitlement policy such as which parts of a proposed project can be used for retail, commercial, and residential space. In some parts of the world taxation policy is being applied in three dimensions. For example, the local taxes that are paid in Singapore are partly determined by the availability of sunlight in the occupied space and the impact of sunlight availability on the surrounding area.


Security personnel are primarily concerned with preventing bad things from happening.  Their infrastructure is made up of monitoring devices like closed-circuit TV cameras and automated number plate recognition systems, physical barriers like fences, bollards, and vehicle barriers, as well as access control infrastructure like security screening areas and sophisticated locks. Security concerns include analyzing the environment for security vulnerabilities, monitoring the environment in real time for suspicious activities, and modeling the impacts of potential unfortunate scenarios. Security personnel need to be able to conduct 3-D line of sight analyses, model blast impact zones, develop restricted area court on scenarios, etc.

Public Safety

In my mind, I find it helpful to define public safety differently from security although the worlds often overlap. I think about security as being primarily concerned with preventing bad things from happening. Public safety on the other hand is primarily concerned with responding after something bad has already happened. Classic public safety agencies, therefore, would be the fire department and emergency medical services. These agencies are often concerned with locations of potentially dangerous items that may exist in an area that they will need to operate in an emergency situation. The locations of hazmat closets and propane tanks are of particular interest to fire departments for example. Fire departments are also very interested in the locations of available fire response equipment like fire extinguishers and stand pipes inside a building and how a given building or set of buildings relates to the available water supply in the surrounding area. Like the security community, public safety personnel are also very interested in understanding how to manage the local transportation infrastructure in the case of an emergency. If they have to evacuate 1500 people from a high-rise building in downtown Manhattan, where do they put those people?  Where do they set up triage centers?  How do they control access and egress from their operational area?  How do they gain access and egress from the buildings that they need to operate in? How do they understand the nature of the population that might be resident in the building at the time of the event?

Space Management

Space Management is primarily the concern of the building owner or occupier.  Space managers are interested in understanding the form, function, assignment, and availability characteristics of their space in 3-D overtime. They are also interested in monitoring and managing various performance metrics of their spaces both individually and collectively. Performance metrics such as cost per square foot, energy consumption per square foot, occupancy rates, and personnel density help the space manager optimize the use of their occupied space. Often a space manager will rely on a computer aided facilities management (CAFM)  system such as Archibus or Centerstone to support workflows related to move management, room reservations, lease administration, etc.  Being able to share geographic information with other facilities management information across system boundaries is a critical requirement of the space management community.

Commercial Real Estate

The commercial real estate community shares a number of the concerns of the space management community but at a slightly less granular scale. Commercial real estate portfolio managers are often interested in understanding their portfolios at the suite or building level rather than at the individual room level. That said, they share a requirement to be able to visualize occupancy rates and other portfolio performance metrics in four dimensions across their portfolio holdings and are often interested in how their portfolio relates to the demographics of the surrounding area.

Public Administration

There are a number of public administration agencies that have interests inside the building. Some of these agencies are interested in regulating land-use entitlement. Their interests are in understanding permitted uses of buildings in three dimensions over time. They will also have a requirement to administer local taxation policy in three dimensions. Other agencies will be concerned with regulating certain activities inside buildings. There are whole host of inspection workflows administered by your typical city administration from restaurant inspections to day care inspections to fire safety inspections and many others. All of these inspection workflows require a basic understanding of the layout of the interior of the building along with the locations of certain domain specific elements. Depending on the workflow, those elements might include exhaust hoods, toilets, sprinkler systems, stand pipes, etc.

Facilities Management

For the purposes of our discussions here, I use the term facilities management to mean the maintenance activities required for a collection of buildings. Facilities management personnel are primarily concerned with the existing condition of the buildings under their control and the locations of anything that might require scheduled or unscheduled maintenance. Facilities management personnel often use some sort of work order management system like SAP or IBM Maximo to help organize and document their work. For this community, the ability to interchange geospatial locations of maintainable assets across system boundaries is a critical requirement.

Environmental Monitoring / Public Health

The environmental health and human safety community is concerned with monitoring environmental quality inside and outside buildings across the landscape.  They will often use a combination of stationary and mobile environmental quality monitoring systems to collect, analyze, and store a variety of environmental quality samples. This community is primarily concerned with understanding the distribution of various contaminants throughout the urban environment both indoors and outdoors over time. They have a need to understand how various factors from blasts to wind to rain might affect dispersion patterns of contamination and to predict under what conditions that contamination might become harmful to human health.

Energy Management

Energy Management is becoming a critical concern for all thoughtful urban designers. As our global population becomes increasingly urbanized, the vast concentrations of buildings (the most dramatic energy consumers on the planet) in our cities greatly concentrates energy consumption in our urban centers and is putting increasing stress on our energy distribution infrastructure and is dramatically driving up the global demand for energy in all forms. In response, campus managers and urban planners are becoming increasingly proactive in monitoring energy consumption on a per building and sometimes a per space basis over time. University campuses are becoming particularly proactive on issues of energy consumption. Many universities have developed policies that prescribe compliance for all university owned buildings with LEED standards for energy efficiency. At the individual building scale, many facilities managers are starting to be much more proactive about using their smart building control systems from Honeywell or Johnson Controls to drive down energy consumption on a per room basis across their portfolio. At a city scale some municipalities, particularly in Europe, are undertaking wholesale infrared imagery collection efforts so that they can identify the most egregious energy inefficiencies in their cities and target those buildings for energy conservation efforts.