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Wednesday, October 13, 2010


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Shelter that sprawls to consume the planet will not protect the survival of its population.

In our time we have become aware that cities sprawl to accommodate growth and leave an expanding core of blight behind. It’s not hard to understand, since it’s cheaper to develop new land than redevelop old; but the easy way out consumes our host. If we choose to meet the challenge of symbiotic survival, we must contain our shelter patterns within sustainable limits; since the remaining life support system is reduced by its expansion.

The effort will reflect an emerging period of awareness.
The need is for intensity measurement, forecasting, and evaluation that can lead the four divisions of our built environment to provide shelter capacity within limits defined by the science of others.
The result will be cities that provide shelter while preserving the land for all dependents.
The form, function, and appearance of the cities that emerge will begin to represent a new period of human achievement.

            The development capacity of land and the intensity constructed affects our quality of life. The ability to predict shelter capacity and measure intensity has been limited by rules of thumb and trial and error exercises at the drawing board, but improving these abilities will help us shelter an increasing population within sustainable limits under desirable circumstances.

We have always realized that shelter (architecture) is essential, but it has taken centuries to recognize that the public health, safety, and welfare are directly affected by the nature of its construction (building codes) and the relationship of its activities (master plans, zoning codes). A glimpse from the Moon however, has revealed that shelter is on a ship sailing through an infinite sea; and common sense tells us we cannot consume the ship nor exceed its capacity. In the case of shelter, capacity is a function of intensity that is molded by design to produce context. Context can improve our quality of life; but leadership is needed to build the knowledge required, since excessive intensity is a threat we call overdevelopment.

Shelter intensity is the relationship of building mass and pavement to open space within and among project areas. Development cover is a component of intensity that includes building cover, parking cover and miscellaneous pavement. The on-site relationship between quantities of development cover and open space produce various degrees of two-dimensional “balance”. When building height is added to building cover it produces three-dimensional building mass. When mass is combined with pavement and off-set by open space, various degrees of intensity are produced. When intensity is combined along a street or within an area, neighborhood intensity emerges. Architecture and landscape architecture convert intensity to context with design. Intensity, however, is the foundation for context within neighborhoods, districts, cities, and regions. Unfortunately, it has not been measured with a consistent yardstick. The lack of an effective measurement system has made it difficult to define acceptable intensity levels, and to predict the shelter capacity that will be produced. This is now feasible, however, for all surface parking and structure parking design concepts, including the “no parking” option; and this potential can be used to measure / evaluate existing context and forecast future options.

            The pie charts in Figure 1 demonstrate the forecasting ability of an intensity equation. The equation applies to one design concept noted as CG1 in Table 1. The charts show that the shelter capacity of this concept increases when parking increases, building height increases, and building footprint decreases. The open space allocation and parking requirement remain constant to illustrate this relationship. Since the charts are not three dimensional, you’ll have to imagine the black wedge increasing in height as its footprint grows smaller. The charts are abstract site plans that represent snapshots of increasing capacity, but do not reveal that the rate of increase for this design concept declines rapidly above five floors. This is shown in Figure 2.

            In practical terms, the pie charts illustrate the relationship between development cover, building height, and open space for one set of variables shown in the upper left-hand corner. Each component within the variable set has an extensive range of possibilities, and the mathematical models that use these variables can produce an unlimited number of design options in response to changes in these values. Four of these options are illustrated by the pie charts in Figure 1, and relate to the CG1 design concept listed. Until the intensity variables of existing context are measured, however, desirable context will remain a matter of opinion based on intuition that is heavily influenced by appearance and return on investment.

             Figure 1 implies that CG1 intensity increases when parking and building height increase and open space remains constant. This is the hypothesis of a designer at the moment however, and remains to be proven. It is a question at the heart of our sustainable future however, since intensity affects our ability to shelter growing populations within sustainable limits. When intensity can be consistently and precisely forecast, the professions that understand its context implications will assume political relevance and leadership potential; since this knowledge will be needed to prescribe the variety required to shelter growing populations within symbiotic limits that do not sacrifice context quality. This is why design matters on every piece of land we transfer from its natural home to the world of our built environment, and the need became obvious on July 20, 1969 when we first saw the Earth as it sailed through infinity protected by a thin film of atmosphere at risk. If we had looked closer, we would have seen ourselves beneath the clouds expanding shelter and paving the face of a natural gift we must not consume. This is a challenge of the highest order. It questions our right to convert land without considering the natural consequences, since these forces tolerate our presence without disclosing the limits of their patience.

City Design

The allocation of land use and intensity is the foundation of a city’s economic stability and quality of life. (See The City is a Farm) Land use is the province of city planning however, and intensity is a function of the architecture constructed. City design must consider both, since the allocation of land use and the construction of intensity is an interrelated symbiotic issue with economic implications. We have no choice. We must produce context and compatibility within limits that yield economic stability and ensure symbiotic harmony.

Intensity is simply the relationship between building mass, pavement, and open space within any project, district, city, or region. The magnitude of intensity is a function of the building mass and pavement constructed in relation to the amount of open space remaining within the buildable land available. The composition that evolves contributes to the “fabric” of a city. This fabric is either densely or loosely woven based on the open space provided. The elements of intensity are the raw material for context. They can be measured, forecast, evaluated, and prescribed to protect our quality of life from the stress of overdevelopment -- while more efficiently using the land to shelter populations and activities within limits that serve our common goal.

When values are assigned to the elements of a design specification template within a forecast model, the intensity predicted is similar within projects of different area and appearance; since these values do not dictate details such as landscape features or building arrangement, separation, shape, function, style, appearance, and construction. In other words, element values represent intensity options. Unfortunately, their implications have not been defined by a research and measurement process, but only this can convert intuition and experience to recorded knowledge.

In the future, leadership may choose among land use and design specification values to define preferred intensity options. These options will then be explored with more detailed context design definition at the drawing board. Decisions will be converted to a strategy that is expressed with contract documents. Construction will complete the process by converting documents to the shelter, intensity, context and appearance envisioned; but it will all begin with the measurement and evaluation of existing values that are the DNA of intensity.

Intensity choices represent leadership decisions that outline the development capacity, economic stability, and social impact that will be produced. The sprawl of a city’s urban form will begin adjusting to the shape, function, and appearance of a symbiotic future when we begin to understand these relationships and the implications of our intensity options; since they determine how we live within cities and preserve our planet beyond.

The need for leadership is based on the argument that the space provided within cities offsets intensity and is a key to our quality of life; while the land preserved beyond determines agricultural capacity and the survival of all life on the planet. The shelter, movement, open space and life support divisions of a city therefore, must be contained within limits defined by the science of others. The objective is to shelter activities and populations within these limits, while ensuring that the intensity and context constructed contributes to the preservation of all life with dignity.

Shelter Classification

            It has become apparent to many that symbiotic survival depends on the balance we strike between the natural world of our planet and the artificial world of our built environment. Thomas Jefferson would have called this a self-evident truth if he had received satellite images, and photographs from Apollo 11, in addition to his notes from Lewis and Clark. We cannot begin to think about balance however, until we understand the potential capacity of land to shelter populations within context parameters that protect their quality of life.

            Shelter capacity is a function of the design concept and specification values involved. When these values are considered separately the result is ineffective leadership, since they interact to produce intensity. This interaction can be predicted by equations embedded within forecast models tailored to each design concept classification. Fortunately, the concepts are limited even though appearance has made them appear infinite. Table 1 illustrates the design classification system that begins a short journey to a forecast model. The remainder of the journey depends on whether the gross land area or the gross building area objective is given.


            The key to an intensity equation is the concept of “core area” when gross land area is given. Net area is found by subtracting rights-of-way and public easements from gross area. Buildable area is found by subtracting all unbuildable open space areas such as ponds, ravines and marshes from the net area. Core area is found by subtracting project open space and miscellaneous pavement percentage estimates from the buildable area. This leaves the core land area available for building cover and parking cover.

An intensity equation relates to a design concept and defines the gross building area GBA that can be produced within a core area based on the specification values entered. Intensity is calculated by dividing the buildable acres defined into the GBA forecast. In other words, intensity equals the gross building area produced per acre of buildable land consumed, and is a statistic equal to the design leadership needed. If gross acres and net acres were used, rather than buildable acres, these statistics would indicate the intensity of the total composition but distort the values required for design leadership.

Intensity options are produced by changing specification values in a design concept forecasting model, or by changing design concepts, and hundreds can be produced in the time it would take to sketch one. The intensity choices selected for context design evaluation are defined by stating the design concept and specification values chosen. A final decision defines the objective for further definition by architecture and landscape architecture.

The CG1 design concept and CG1L forecast model balance parking cover and building cover relationships within the core area of a given gross land area based on the values entered. Parking spaces within a core area determine the gross building area that can be supported, and increasing building height reduces the land required for building cover. This leaves more core area for parking. Since parking spaces determine the gross building area that can be supported, maximum development capacity is a function of the ideal relationship between parking cover and building cover within the core development area based on the number of floors contemplated and other design specification values entered.

For example, when land area is given, the optimum relationship between parking cover, PCA, and building cover, BCA, within the core area, CORE, of a CG1 design concept is a function of the core mass divided by a capacity coefficient. The core mass is simply a function of the core area available (CORE) multiplied by the number of building floors (f) contemplated. The capacity coefficient is a function of the building floors (f) and parking specifications involved (s and a). This equation is derived in Chapter 21 of Land Development Calculations, second edition. It is repeated here and embedded in the CG1L forecast model of the Development Capacity Evaluation software attached to the book.

A Design Principle

            When the CG1L equation is plotted in Figure 2, it reveals a design principle that can be expressed in the following terms:

When a CG1 design concept is considered, the rate of increase in development capacity declines at an accelerating rate as the number of building floors increase

Figure 2 illustrates this principle and clearly shows the dramatically decreasing rate of increase in gross building area, or development capacity, as building height pushes above five floors. It is based on a 30% project open space provision and is a very popular suburban design concept, but the choice involves a relatively inefficient use of the land. If a larger building on the same land area were desired, based on the same design concept; a larger core area would be required. The increase however, would come at the expense of project open space and/or other specification values. The efficiency profile in Figure 2 would show the same rapidly decreasing rate of increase in development capacity, but start at a higher point on the Y-axis. In fact, any change to design specification values will alter the intensity and context created, but the relationships remain constant and the implications remain a matter of opinion.

            Figure 2 confirms the intuition of many designers and converts this intuition to knowledge. The context implications of design specifications and intensity options remain to be explored; but there is another point to be made. Figure 2 demonstrates that planning and design issues can be expressed in mathematical terms. This has the power to persuade in a political environment that cannot be avoided. It also improves our ability to collaborate with the science of others; since the land our planet can donate to shelter, and the development capacity of this land, is becoming an issue of survival. The answers we find will be reflected in the architecture of our solutions, the context they occupy, and the city design we create with the four divisions of our built environment.


The efficient use of land is a function of the generic design concept chosen, but efficiency does not preserve open space within or beyond cities; and context is left to chance until open space is specified. Shelter capacity is a function of the core area remaining. In the end, it is all about design with space. The space required to preserve the natural world, the space required for agriculture, and the space required to relieve intensity within the artificial world of our presence. The open space, movement, and life support systems of a city exist to serve the activities sheltered by architecture. As the population grows, the intensity required may come at the expense of open space. It may be reduced as a domain within the built environment, reduced as a component of project areas, or converted from its home in the natural world. In any event, lack of open space preservation will alter our relationship to both our natural partner and the context of our built environment. This has profound implications and we must be able to measure, classify, and forecast the capacity of cities within symbiotic limits before we can lead these competing worlds toward our common goal.

Open space is unique. It is an opposing world of ecology that has become an environmental battlefield, a domain within our built environment, and a component of project design. It must be separated and preserved to protect our future while also included within the built environment to mitigate intensity. This involves city design decisions we have not begun to explore in the detail required, since land use allocation and intensity decisions not only affect our quality of life and symbiotic future, but the economic stability of cities and nations as well. This will challenge our ability to adapt until we acknowledge that we are guests on the land of our planet -- and abuse threatens survival on this unstable boat in an infinite sea.

            The urban form of a city indicates its intensity and shelter capacity. Land use allocation and regulation are almost invisible, but determine the scope of activities sheltered and the revenue received to support shared services. Social activity occupies capacity and often multiplies intensity. Economic stability is a function of land use activity and intensity allocation. The collective impact of these physical, social and economic characteristics adds a psychological dimension. This reaction will indicate our progress in protecting the health, safety, and welfare of expanding populations within sustainable limits. The planet’s reaction will determine our progress toward a common goal that cannot be ignored.

Author Note: Many professions are needed for the collaborative research required to improve the stewardship of land through city design; and improvement is needed to justify the authority required. This article mentions several professions, but is equally relevant to many unmentioned who are involved with the construction of intensity, its impact on our quality of life, and its relationship to a silent partner who adapts without compromise.
Portions of this article were excerpted and edited from the second edition of my book, Land Development Calculations, and its attached forecasting software, Development Capacity Evaluation, v2.0 published by The McGraw-Hill Companies, 2010. The book can be found on

The following articles can be read on my blog, Cities and Design, at

1)             "Replacing Density" discusses its leadership weakness and intensity alternative,
2)             "The Limits of Shelter Capacity" provides expanded detail regarding intensity,
3)             “The City is a Farm” discusses the relationship of intensity to economic development,
4)             "The Disorganized Zoning Ordinance" outlines the legislative confusion that impedes leadership progress,
5)             “Examining Architecture” takes a closer look at a piece of the city design puzzle,
6)             “The Variance Trap” illustrates development regulation weakness with a residential forecast model from the Development Capacity Evaluation (DCE) software collection,
7)             “City Design with Space” discusses the overlooked role of project open space with a non-residential forecast model from the DCE collection,
8)             “The Core of Our Built Environment” identifies the nucleus of development capacity
9)             “Ponzi Schemes and Land Use Plans” offers an alternative to annexation and sprawl.
10)         “Where Does Sustainability Begin?” discusses the importance of land in a competition between our natural and built environments.
11)         “Economic Development Is Missing a Strategy” discusses the intelligence and strategic planning required to identify economic development objectives on the road to a sustainable future.

These articles have been deleted from my blog but are available upon request:

1)             The Concept of City Design” includes an overview and suggested research agenda,
2)             “Politics and Planning” is an argument in support of the effort, and
3)             “Context Measurement” outlines a suggested research yardstick.

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