Julie Campoli, a landscape architect, land planner and principal of Terra Firma Urban Design in Burlington, Vermont, and Alex MacLean, a photographer, trained architect and principal of Landslides Aerial Photography in Cambridge, Massachusetts, have worked collaboratively for more than two years to research and document the phenomenon of residential density. They have developed a catalog of more than 300 aerial photographs that illustrate a wide range of density in both established and newer neighborhoods around the country. The Lincoln Institute has supported their work, which has been presented through lectures and courses and is available as a digital working paper titled “Visualizing Density” on the Institute’s website.
How did you join forces to begin this work on photographing and measuring density as a visualization tool for community planning?
We both have a longstanding interest in using visual images to illuminate land use issues. For years Alex has recorded human imprints on the land quite eloquently through his aerial photography. I am constantly experimenting with graphic techniques to communicate design ideas and to express how we shape the built environment. In our first collaboration, Above and Beyond (written with planner Elizabeth Humstone, APA Planners Press, 2001), we employed aerial photographs, many of which were digitally enhanced, to show how and why landscapes change over time. Our intent was to help readers understand the land development process by representing it in a very graphic way.
As we completed that book, we could see that fear of density was emerging as a major obstacle to the type of compact, infill development we were advocating. It became apparent to us that, although people liked the idea of channeling growth into existing areas, they seemed to balk at the reality. We saw many instances where developers trying to build higher-density housing met stiff resistance from a public who equated density with overcrowding. In many communities density is allowed and often encouraged at the policy level, but it is rejected at the implementation stage, mainly because the public has trouble accepting the high numbers associated with dense development.
We became interested in this ambivalent attitude and wanted to look more closely at those density numbers. It seemed to us that a preoccupation with numbers and a lack of visual information was at the heart of the density problem. We thought that some of the graphic approaches we used in Above and Beyond might help people understand the visual aspects of the density issue. We wanted to translate the numbers that were associated with various density levels into mental images, specifically to show what the density numbers mean in terms of real living places.
Why is density such a difficult concept to understand and visualize?
Anything is difficult to visualize if you have only a few pieces of information from which to conjure your mental image. Density is most often represented as a mathematical ratio. It is the number of units divided by the number of acres, or the gross floor area of a building divided by the size of its site. These measurements describe a place as a numerical relationship, which only takes you so far in being able to imagine it. Such information fails to convey the “look and feel” of density and often creates confusion in the community planning process.
An individual’s response to the issue of density often depends on past experience and the images that happen to be part of one’s visual memory. Someone might associate higher-density numbers with an image of Boston’s historic Beacon Hill neighborhood or central Savannah, but high-density development is more frequently imagined as something negative. This is the gap between density as it is measured and density as it is perceived. One is a rational process. The other is not.
What does your density catalog illustrate?
The catalog contains aerial photographs of neighborhoods in several regions of the country. They are arranged according to density level, ranging from exurban houses on 2-acre lots to urban high-rise apartments at 96 units per acre. Each site is photographed from a series of viewpoints to show its layout, details and context. The catalog can be used to compare different neighborhoods at the same density or to see how the design and arrangement of buildings changes as density levels rise. We included a wide array of street patterns, building types and open spaces, demonstrating how the manipulation of these components can create endless variations on neighborhood form.
What becomes apparent to anyone looking at the catalog is that there are many ways to shape density, and some are more appealing than others. We don’t try to suggest which images are “good” or which are “bad”; we let the viewer draw his or her own conclusions. Our hope is that after viewing the catalog people will not only have a clearer idea of what 5 units or 20 units per acre looks like, but, more important, they will be able to imagine attractive, higher-density neighborhoods for their own communities.
How do you measure density?
In the first phase of our project we focused on residential density as measured in units per acre. Using the 2000 U.S. Census, it is possible to find the number of housing units for any census block in the nation. We photographed neighborhoods across the country and calculated the number of units per acre for each site by determining the number of units from the census data and then dividing by the acreage.
Units-per-acre is a measurement commonly used in local zoning and in the review of development projects. It is familiar and understandable to the average person dealing with local density issues and provides a relatively accurate measure for primarily residential neighborhoods. In calculating the density of mixed-use or commercial sites, floor area ratio is a more precise measurement. We plan to extend our analysis to mixed and other uses with this measurement in the next phase of our work, to see how various design approaches can accommodate higher densities.
What is the connection between density and design
Design plays a profound role in the success of compact development. Although it seems that the smart growth movement is confronting a density problem, it’s really more of a design challenge. It is not density but design that determines the physical character and quality of a place. This was made clear to us when we found examples of existing neighborhoods with widely varying character yet the same density. One area might have a sense of spaciousness and privacy, while another appears cramped. Different design approaches can dramatically affect one’s perception of density. This defies the commonly held belief that fitting more people into a smaller area inevitably results in a less appealing living environment. Higher densities, especially on infill sites, pose a greater challenge to designers, but they do not dictate a certain type of form or character.
As we measured the density of existing neighborhoods and assembled the catalog, we began to see specifically how design accommodates density. The most appealing neighborhoods had a coherent structure, well-defined spaces and carefully articulated buildings. They were the kinds of places that offered a lot of variety in a small area. If planners and developers want to promote density, it is essential to identify the amenities that make a neighborhood desirable and to replicate them wherever possible. Interconnected neighborhoods with high-quality public, private and green spaces, and a diversity of building types and styles, will win more supporters in the permit process and buyers in the real estate market than those neighborhoods without such amenities.
How can planners, developers and community residents use the catalog to achieve the principles of smart growth in their local decision making to design new neighborhoods?
The catalog can be used as a tool to refocus the density discussion away from numerical measurements and onto design issues. In our workshops we ask participants to examine several photographs from the catalog showing nine neighborhoods that have a similar density but very different layouts. In articulating their impressions of the places they see, what they like and why, they are forced to think about how the design—the pattern of streets, the architecture or the presence of greenery—affects the quality of the place.
In a town planning process, if residents participate in a similar exercise, they will take the first steps toward a community vision for compact neighborhoods. They can see that the same design principles behind those preferred places can be used to create appealing dense neighborhoods in their own communities. Once they develop a vision for what they want, they can use the planning and regulatory process to guide development in that direction.
Developers of urban infill housing often find themselves on the defensive in the permit process, arguing that density does not necessarily equal crowding. The catalog provides images that can help bolster their case. More importantly, it offers developers, architects and landscape architects visual information on historic and contemporary models of compact development. They can use the photographs to inform their design process, instilling features of the best neighborhoods into their own projects.
What are some of your conclusions about why understanding density is so important to the planning process?
Density is absolutely essential to building strong communities and preventing sprawl. It’s also a growing reality in the real estate market. Instead of denying it or barely tolerating it, we can embrace density. The trick is to shape it in a way that supports community goals of urban vitality and provides people with high-quality living places. At this point though, we seem to be a long way from embracing density. It may be a deep cultural bias or simply that many Americans are unfamiliar the benefits of density, such as more choices and convenience to urban amenities. And in many cases, they have not been shown that neighborhoods of multifamily homes, apartments and houses on small lots can be beautiful and highly valued. We hope that our residential density project and the digital catalog can provide some material to fill the void.
Julie Campoli is principal of Terra Firma Urban Design in Burlington, Vermont, and Alex MacLean is principal of Landslides Aerial Photography in Cambridge, Massachusetts.