Map Overlay Analysis and the Richmond Parkway
Ian McHarg (1920-2001) achieved numerous accomplishments in the field of landscape architecture and urban planning and was one of the true pioneers of the environmental movement. Born in Glasgow, Scotland, McHarg graduated from Harvard University and later established the Department of Landscape Architecture at the University of Pennsylvania. During the course of his lifetime, McHarg hosted his own television show on CBS “The House We Live In” (1960-1961), in which he discussed human attitudes toward the environment with top intellectuals of the day. In 1969 he published the landmark influential book “Design With Nature” which introduced environmental concerns to the world of landscape architecture. McHarg was the planner in charge of important projects such as the Inner Harbor in Baltimore and the Woodlands in Houston. He became world renowned for his philosophy of incorporating environmental concerns into designs, leading to numerous awards and recognition including the Harvard Lifetime Achievement Award, the Thomas Jefferson Foundation Medal in Architecture, the Japan Prize in City and Regional Planning, and in 1990 he was bestowed the National Medal of Arts from the President of the United States. However, it was his early use of photographic map overlay analysis, particularly in the case of route planning for the Richmond Parkway of Staten Island (later renamed the Korean War Veteran’s Memorial Parkway) that established him as one of the early pioneers of GIS. Due to this early use of multidisciplinary-based suitability analysis and his continued accomplishment in the field of GIS during his lifetime, McHarg became the first recipient to earn the lifetime achievement award at the GIS conference in Vancouver, Canada in 1995.
THE RICHMOND PARKWAY:
As the American Interstate Highway System began to develop following World War II, the primary focus of highway planners was on cost-minimization and efficiency in route selection. Environmental consideration were not addressed in transportation planning and design at the time, particularly as there was no efficient method in place to store, process, or present spatial data about the natural environment in a meaningful and useful manner. This was the issue facing the planners of the Richmond Parkway of Staten Island.
Planning for the Richmond Parkway initially began back in 1930 when then New York City planning coordinator and parks commissioner Robert Moses introduced his master transportation plan for the New York City parkway system. It was not until 1965 however that the New York City Board of Estimate approved the proposed route for the parkway and construction contracts were finally granted. The parkway was designed to provide limited-access traffic between Long Island and New Jersey by connecting the southern portion of Staten Island to the Staten Island Expressway and hence the Verranzano-Narrows Bridge. Construction on the 9.5 mile-long parkway began in 1966 from the southwest tip of the island at Arthur Kill Rd. northeast toward Richmond Avenue near the center of the island. Considerable controversy was sparked however by the parkway’s intended route through Latourette Park in the Staten Island Greenbelt. The following year construction was stopped by the New York City Department of Highways and the engineering consulting firm of Lockwood, Kessler and Bartlett was commissioned to develop alternative routes for the remainder of the Richmond Parkway. The proposed routes however were met with protest from local residents and in 1966 Mayor John Lindsay ordered a halt to all construction north of Richmond Avenue.
To break the deadlock and attempt to devise a more suitable route that would meet residents’ demands, McHarg’s firm was commissioned in 1968 by the New York City Parks Department to determine an alignment that would result in the “least social cost”. In order to determine an appropriate route, McHarg first considered a number of factors that would affect “social values”. These factors included the following:
● Slope ● Surface drainage ● Soil drainage ● Bedrock foundation
● Soil foundation ● Erosion susceptibility ● Land values ● Tidal inundation
● Historic values ● Scenic values ● Forest values ● Water values (lakes, ponds, streams, etc.)
● Recreation values ● Wildlife values ● Residential values ● Institutional values
After these sixteen important factors were identified, McHarg developed an approach using map overlay analysis. Each characteristic was mapped on its own transparency and three different tones of shading were utilized, ranging from the darkest for the greatest amount of value or cost to the lightest for least value or cost. Then by overlaying the transparencies into a single stack the optimal location for routing the parkway that would result in the least social cost was revealed. The results revealed that the current planned routing for the parkway in fact cut through some of the most valuable land from a social cost perspective and would destroy important scenic, recreational and wildlife resources on the island. McHarg’s solution was an alternative routing through an area to the west of the greenbelt, saving valuable forest and parkland. (The following map demonstrates both the initial proposed route through La Tourette Park and the alternative route proposed as a result of McHarg’s analysis.)
Ultimately the rejection of a $3.5 billion statewide transportation bond issue in 1973 cancelled the entire project and the only portion of the Richmond Parkway to be completed was a 4.7 mile-long stretch along Drumgoogle Boulevard. McHarg’s analysis however was not in vain, and the impact of the report and its findings eventually lead to the inclusion of environmental impact studies in all further federally aided highway projects from 1970 forward. In addition, the map overlay analysis used by McHarg lead to further development of modern GIS mapping programs in route planning studies.
Today the Staten Island Greenbelt is one of the largest natural areas within the five boroughs of New York City and retains much of its original and unspoiled environmental characteristics.
Ian McHarg passed away on March 5, 2001 of pulmonary disease at the age of 80. During his lifetime, Ian McHarg’s impact on both GIS and the environmental movement were legendary. His legacy lives on however, as more than 1,500 former graduate students under the direction of McHarg have now moved on to become deans and department heads of learning institutions throughout the world, while others have become high placed people in both government and the private sector. As James Corner, chair and associate professor of landscape architecture and regional planning for the University of Pennsylvania summarized at his memorial service, “Ian McHarg was one of the great cultural figures in 20th century planning and design”…”He painted an incredibly rich and exuberant picture of the organic world and the various forms of life it continues to body forth, and from this he conjured up the vision for a more wholesome and productive world metropolis.”
Levy, John M. Contemporary Urban Planning. Upper Saddle River, New Jersey: Prentice Hall Publications, 2003.