Wednesday, December 23, 2009

Representing Transects

Picking up on a couple of great posts on transect delineation over at FAD (and a lively discussion thread as well that is worth checking out), this idea continues to permeate the discussions around the Urban Edge.

:: image via CATS

Taking a different tack than the critique of the transect per se (of which there is plenty), I've been tooling around looking at ways to break out of the traditional mo
des of representation when showing the experience of the transect and the ability to communicate this to a viewer. As we know, the common transect has a simple expansion of the typical section cut technique. In a natural condition this slices through a number of ecosystems:

:: image via CATS

A common reference is this diagram that has become a touchstone for New Urbanist applied theory, outlining a generalized zoning diagram with their associated T-zones (transect zones):

:: image via CATS

The definition from the CATS site gives a quick idea of the concept of transect which borrows from the ecological concept: "A transect is a cut or path through part of the env
ironment showing a range of different habitats. Biologists and ecologists use transects to study the many symbiotic elements that contribute to habitats where certain plants and animals thrive. Human beings also thrive in different habitats. Some people prefer urban centers and would suffer in a rural place, while others thrive in the rural or sub-urban zones. Before the automobile, American development patterns were walkable, and transects within towns and city neighborhoods revealed areas that were less urban and more urban in character. This urbanism could be analyzed as natural transects are analyzed."

The CATS site has a range of transect images that provide some good ideas for representation. The most simple, falling along the natural ecosystem transect comes from McHarg's Design with Nature, and is represented by more of a typical scaled sectional cut through a dune landscape. An interesting interpretation via the CATS site that sort of oversimplifies the work as anti-humanitarian: "McHarg’s brilliant analytical/ operational system never integrated the human habitat, which was simply relegated to wherever nature was least valuable. In this sense. it is a step backwards from the Geddes transect of a half-century earlier."

:: image via CATS

Another adaptation is from the transect done for an Regional Plan for Western New York State shows some of the precedents in representation and analysis, which are the seeds of modern transect studies: "A regional transect of natural conditions and existing thoroughfares, drawn in 1926 with compact towns and villages, is overlaid with the present SmartCode's three basic Community types in purple."

:: image via CATS

These were inspired by the more generalized earlier transect from planner Patrick Geddes - which is delineated with this more graphical 'Valley Section' showing a typical natural system overlaid with use zones showing, for lack of a better word, exploitation zones of the landscape section. I guess that's the step backwards we're talking about by not including overt humanity into the equation.

:: image via CATS

I find it fascinating that many of the concepts in the New Urbanist pantheon are 'borrowed' from ecology including transects, zones, quadrats, and such. It's also inte
resting that these are as much a graphical exercise as they are a planning one, with a very specific intent and bias from the drawings (show me a drawing that isn't biased in some way?). For instance the 'wedge' shape denotes relative usage of land: "The wedge shape of this naturalistic illustration signifies that the more urban Transect Zones, with their greater density, use less land per capita than the more rural zones."

:: image via CATS

To say that any of these drawings is merely inert is sort of laughable - as there's typically an agenda at work behind the scenes (literally behind the scenography of these graphics). That's not to say there's some nefariousness, as they are generalized stereotypes and tools for u
se in planning, and application of some of the more robust planning materials like SmartCode (more on this later). The more traditional vertical transect drawings start to look like panels in a cartoon, showing a typical American and European iteration of the panels:

:: images via CATS

There's some parallels with the idea of movement as captured in graphic novels, film storyboards, flip-books and the like. There is also a reference back to Chinese scrolls, where the entirety of a transect can be captured on a never-ending length of paper... at an appropriate scale could be new maps of territories.

:: images via CATS

One commentor on FAD alluded to this image from R.Crumb 'A Short History of America' (posted here on L+U) which is graphically a little too similar to the stylized transects above:

:: (click to enlarge) - image via R. Crumb

Check out the Center for Applied Transect Studies site for some more great info on the topic and some great historical graphic. More about this soon, as I'm continuing to look at how the transect (the generic or ecological term that is akin to section) is valuable in urban exploration, notation, and planning in the particular context of Portland's urban edge.

There's much to learn from this in terms of both technical application as well as marketing cachet, as it leads to a pretty compelling (albeit graphically utopian or manipulated) version of (new?) urbanism that many people respond favorably to. The real question is: Does this work on a City with an urban growth boundary, or does it need the more gradual filtering of density from sprawl to really accentuate the beauty of the transect? Do we skip over a few T-zones in this way or does the construct fall apart? Can this be captured in selected explorations of our urban edge?

How to represent a line, which is a place itself and a container for a place delineating in- and out, that is dynamic with flex and pull and change of weather as well as politics and economics? It's gonna be a fun ride.


  1. I recently came across your blog and have been reading along. I thought I would leave my first comment. I don't know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.


  2. Thanks for your interesting summary of Transect imagery. A comment in response to your "real question" about workable locations for applying the Transect: It is essential to understand the scales that the Transect is intended to be implemented at.

    The Transect applies to the block and lot scales, shaping elements like building setbacks, street widths, and block sizes. And to a lesser degree, it applies to the neighborhood scale, ensuring a mix of Transect zones within each neighborhood for access to needed destinations, well-connected street layouts, and so on. Transect zones are relatively small in area, from a few blocks to tens of acres at maximum.

    The Transect does not apply to the city or regional scales. The SmartCode has a different framework for those scales, the preservation and growth sectors. Within sectors are community units, and within community units are Transect zones. It's a multilayered, hierarchical framework.

    So the answer to your question is, the Transect works with or without a growth boundary because growth boundaries are regional demarcations. In fact, a harder edge between urban and rural is the new urbanist ideal, as seen in the CNU Charter: "Development patterns should not blur or eradicate the edges of the metropolis."

  3. Great Post. I have always been attracted to the simplicity of the transect and its ability to convey a lot of information, albeit general, in a graphically pleasing way. Applying the transect to the urban growth boundary is a tricky, but I think doable task.

    There is a bit of a disconnect between the UGB line on the map and the resulting landscape. The development takes time to catch up with planning. I was driving through Damascus the other day the the farms gave way quickly to the dense neighborhoods. Between those were the remnants of the 3-5 acre rural lots. It was all in all a spotty, hard to comprehend landscape. It would make for an interesting looking transect. What I see happening more and more is the urban growth boundary is not a circle but more of a blob with arms. It would be interesting to see what a transect looks like that starts in the UGB travels through the rural area and reenters the UGB in another arm.

    Thanks for the collection of info.

  4. Michelle, I have been thinking about your post, because the application of the Transect to walkable urbanism intends just that - the wave-like action of urban separated by rural (although each "urban" area has its own characteristics and level of urbanism, from hamlet to village to city to regional center).

    The primary point is that each "increment" of urbanism must be, at minimum, an approximate 1/4 mile" pedestrian shed" to make it truly sustainable (i.e., meaning most daily needs are within walking distance and rich with a diversity of living, working and shopping opportunities).

    This assumes the largest lots are primarily on the neighborhood edge as a transition from urban to rural, adjacent preferably to rural agriculture, and that a mix of ag and preserved "wilderness" likewise separate communities.

    This concept can be valid in a number of urban settings, from small town neighborhoods to highly urban areas.

    While with PlaceMakers, we designed a community of eight hamlets and saved the majority of land between each one as natural landscape. (The original plan had been to fully develop in sprawl mode the entire land area.) The Waters is outside Montgomery, AL, and hamlet one is well underway. Here is a link to the Master Plan:

    It is a good example of how one can plan complete neighborhoods, maintain a small town feel while building compactly to ensure walkability, and conserve land. There are many design tools to accomplish similar effects in more urban areas, from conservation easements to urban agriculture to regional parks and greenways.

    I love Germany, where the urban edge ends abruptly and agriculture or forests take over. (Large suburban size lots are almost nonexistent there, where efficiency seems to trump other considerations and public shared space is well-designed and abundant.)

    Ann Daigle
    Community Design & Plan Strategy


Note: Only a member of this blog may post a comment.