Visualizing Density

By Julie Campoli and Alex S. MacLean

Lincoln Institute of Land Policy, 2007, 160 pp., paperbound $39.95.

This book would fill a pressing need if only its producers had gone a couple of steps further. In the foreword, Armando Carbonell of the Lincoln Institute of Land Policy says the Institute commissioned Visualizing Density “to help planners, designers, public officials, and citizens better understand — and better communicate to others — the concept of density as it applies to the residential environment.”
Fine. Americans need help to see that living compactly can be not only environmentally responsible but also more enjoyable and convenient than living in spread-out, overwhelmingly automobile-dependent surroundings. Much development in the US has not been planned and designed well, so it makes perfect sense to publish a book filled with examples of how houses and housing are organized on the land, at every density — from less than one unit an acre to more than 200 units per acre.

But why communicate this knowledge mostly through aerial photos? Alex MacLean’s photos are fascinating in their way — I spent a lot of time poring over them — but the Lincoln Institute is kidding itself if it thinks that people can distinguish good development from bad mostly by peering down from the sky. To understand what a particular form of development does to or for people, it’s essential to see the buildings and the environment mainly from pedestrian-eye-level. That is what Visualizing Density adamantly refuses to do.

This is a shame, because the text of approximately the first 60 pages is chock-full of valuable insights. Landscape architect and urban designer Julie Campoli adeptly explains the reasons why many contemporary Americans resist living close together. “Many new subdivisions create density without amenities,” Campoli points out. “They are crowded and monotonous,” offering few environmental or economic benefits, she says. Because of rapid population growth — the number of Americans rose by 19 million in just the past six years — the US will need to construct 60 million new dwellings in the next 25 years. If this is done in the disconnected, spread-out way that the nation has chosen for the past several decades, it “will place a great strain on our environment and our future economy,” she warns.

“An urban resident living a density of 12 units per acre generates about one-third less of … harmful emissions than someone driving the miles necessary to live at a density of 3 units per acre,” Campoli notes, in just one example of why higher density is better. She advises against “dense sprawl,” the kind of development seen in Las Vegas, where houses are packed together in a single-use, car-dependent fashion, “without much variation to distinguish one district from another.” Campoli delivers concise, useful advice about human scale, “green infrastructure,” outdoor rooms, enclosure, privacy, granny flats, parking, and other topics. This part of the book should be extremely useful for planning board members and anyone else who lacks professional training in planning and design.

The second half of the book consists of a “density catalog,” more than 80 pages illustrating the differing ways in which housing can be developed at various densities. This section includes diagrams of street patterns, but mostly it presents MacLean’s full-color aerial photos, which unfortunately don’t give readers the understanding they need.

Readers require views at ground-level so they can see how livable a pattern really is. They also need a brief discussion of each set of illustrations. For instance, four photos and a street diagram present a development tersely identified as “Boca Raton, FL 7.8 units/acre.” The reader isn’t told that this is Charleston Place, a 25-year-old Duany Plater-Zyberk development that has proven immensely popular with its residents, in part because its house, block, street, walkway, and open-space patterns encourage walking and sociability. Few readers will comprehend the virtues of Charleston Place without an explanation of how the townhouses address the street, how they provide private courtyards, and other basic features of the layout. The density catalog is mum on all this. And the higher the density of the developments pictured in the book, the less helpful the aerial photos tend to be.

I’m told the Lincoln Institute is well-funded. If so, the Institute should spend some of its money to revise the density catalog and republish the book, adding ground-level photos and adding concise explanations of the advantages and disadvantages associated with each of the 256 examples. The resulting book would contribute tremendously to public understanding. Visualizing Density now falls frustratingly short of its aims. With expansion and refinement, however, it could become an indispensable guide to better development.