Analysis

Published on June 2016 | Categories: Documents | Downloads: 78 | Comments: 0 | Views: 446
of 11
Download PDF   Embed   Report

Comments

Content

The Emerald Research Register for this journal is available at http://www.emeraldinsight.com/researchregister

The current issue and full text archive of this journal is available at http://www.emeraldinsight.com/1477-7835.htm

MEQ 14,5

604

An analysis of attributes affecting urban open space design and their environmental implications
S.M. Lo
Department of Building and Construction, City University of Hong Kong, Kowloon, Hong Kong

C.Y. Yiu
Department of Building and Real Estate, Hong Kong Polytechnic University, Kowloon, Hong Kong, and

Alan Lo
Department of Building and Construction, City University of Hong Kong, Kowloon, Hong Kong
Keywords Urban areas, Open spaces, Analytic hierarchy process, Integration Abstract This paper analyses the factors influencing the design of urban open space from the users’ perspective. A questionnaire survey has been carried out in Hong Kong to identify the importance of each design attribute with the aid of the analytic hierarchy process. The results show that microclimate is the most important criteria. Planting and sunlight rank the highest in the sub-criteria indicating that natural environment is the most treasured by the users of urban open spaces. Accessibility is also one of the important criteria. Hard landscape, on the contrary, ranks the least. The findings imply that urban open space cannot be considered in isolation, but an urban integration approach is required.

Management of Environmental Quality: An International Journal Vol. 14 No. 5, 2003 pp. 604-614 q MCB UP Limited 1477-7835 DOI 10.1108/14777830310495759

1. Introduction The existence of urban open spaces is crucial to people’s life, especially in high density cities such as Hong Kong. It is commonly agreed that visual and physical exposure to natural environment is conducive to physiological and psychological health. However, the design of urban spaces has been criticized as largely failing to serve their intended users’ needs. Client briefs and design contexts seldom address users’ needs or the ways how it can function to serve their needs. Carr et al. (1992), for example, challenge that urban open spaces are often designed for commercial reasons, to act as corporate emblems. Very few researchers so far have tried to identify the importance of design attributes to an urban space design from human perspective. Yet, Cherulnik (1993) highlights that designers and planners differ widely in the attention they give to the needs of everyday users of the physical environment. Therefore, a study of this kind is particularly valuable for encouraging designers to produce more

successful designs. The findings can feedback to the training of designers to strengthen the built-for-the-users design concept. This paper aims at identifying the critical design attributes affecting urban open space design. The attributes will be identified by carrying out a comprehensive literature review as stated in the following section. Then the importance of each attribute will be assessed by means of a questionnaire survey with the aid of the analytic hierarchy process. The methodology and questionnaire setting will be presented in Section 3 and the results of the survey will be discussed in Section 4. Finally, conclusions will be given in Section 5. 2. Literature review Jackson (1985) defined an urban open space as an urban form that draws people together for passive enjoyment. Lynch (1981) considered that urban open space contains features meant to attract groups of people and to facilitate meetings. Marcus and Francis (1990) distinguished urban open space from sidewalk by stating that the former is a place in its own right rather than a space to pass through. The links between urban spaces and environmental quality were outlined in Rogers (1999), which stated that “a clear articulation of public space connects neighbourhoods to each other and links people within localities to their social institutions. They do not only provide outdoor areas to relax and enjoy the urban experience, venues for activities and places for walking or sitting-out, but they also establish a balance between people and their environment”. In other words, a high quality environment can only be achieved by “urban integration”, which considers urban open space as a crucial part of the urban landscape. It does not only form a local focal point, but it also connects the neighbourhoods and acts as a vital glue between buildings in strengthening the communities. Friedmann et al. (1978) was one of the earliest to carry out research on the evaluation of urban open space. Substantial resources have been devoted to improving urban open spaces as a result of a growing concern for the quality of the public environment of cities. Environment-behaviour research on urban open space design has also been called on in Cherulnik (1993). Parsons (1991) argued that visual exposure to the natural environment has anxiety-reducing effects from an environmental psychology point of view. In other words, urban open space is of utmost importance to the scurry and scramble of city life. The human preference of the design attributes for urban open spaces would therefore make a difference to the success of the design. Before the 1970s, there was virtually no concern on the behavioural aspects of the use of urban open space, let alone their psychological implications. Gibberd (1967) dealt primarily with the sculptural arrangements of buildings and spaces, with almost no reference to their actual day-to-day use. Eckbo

Urban open space design

605

MEQ 14,5

606

(1964) commented on existing designed spaces from pure aesthetic point of view with little reference to behavioural responses. Cullen (1961) also emphasized only visual expression on urban landscape design. Tandy (1972) started to consider users’ behaviour in some forms of open space and Rowe and Koetter (1978) expressed concern on human activity, interaction, control and values on the design of open space. Pushkarev and Zupan (1975) was one of the earliest environmentbehaviour studies in urban open space design. They produced a sophisticated analysis of pedestrian behaviour on streets and plazas. Whyte (1980) reported a series of plaza studies using stop-frame filming and behavioural observations. Their findings have been used to establish general guidelines for the design of urban open space. Gehl (1987) focused on the often ignored activities such as walking, standing and sitting in the spaces between buildings to investigate the specific requirements on the man-made environment. Marcus and Francis (1990) provided an excellent source of ideas and information on the design of urban open space. Case studies were provided to describe how the attributes function to the satisfaction of users. More recently, Carr (1992) and Rubenstein (1992) discussed the theory and practice of humanizing the environment and offer guidance for improving the design, management and the use of public space. The need for evaluation of environmental design has gained recognition in behavioural scientists as well as designers in the late 1970s (Friedmann et al., 1978). However, most of the previous studies were not adopting rigorous evaluation methods. For example, in Nager and Wentworth’s (1976) study of the Bryant Park in mid-town Manhattan, they simply employed direct rating method. Whyte (1980) investigated 18 urban open spaces in Manhattan by simple correlation method. The study concluded that the influence of the landscape and architectural characteristics of plaza design, such as seating, visibility from the street, and shelter from the weather, seem eminently reasonable, despite the absence of statistical controls. Kaplan and Kaplan (1990) and Godbey et al. (1992) found that good accessibility is one of the most important attributes of urban open space. On the other hand, Corraliza (2000) found that the non-spatial qualities of landscape are just as important as any spatial qualities. Worpole (2000) also found that parks serve the purpose of retaining privacy in his UK research. Rogers (1999) further posited that urban open spaces should be integrated into urban lives. Leveratto (2002) therefore argued that urban form plays an important role in defining the performance of open space. Other major literatures concerning the design attributes for urban open space include Pushkarev and Zupan (1975), Gehl (1987), Marcus and Francis (1990), Carr et al. (1992), Rubenstein (1992), Cherulnik (1993) and Tomalin (1998). Their attributes are summarized in the following section.

3. Methodology 3.1. Attributes From the review of the eight important literatures on design attributes in urban open space, 23 attributes can be identified as shown in Table I. Among the 23 attributes, 12 of them are adopted for this study for their compatibility in the Hong Kong environment. Since the study is concentrating on the design elements of urban open space, the factors such as location and size are ignored in the survey. The selected 12 attributes can be grouped under four main criteria, namely seating, microclimate, boundaries and landscape. The main and sub criteria are shown in Table II. Kaplan (1982) contended that a city-dweller is more appreciative of “green” places. Milgram (1970) considered a public plaza a place to escape from the confusion, noise, crowds and “overload” in the urban settings. Wachs (1979) also argued that a “green” plaza is a haven and a “stimulus shelter”. Hartig et al. (1997), Kaplan (1983, 1985) and Kaplan and Kaplan (1990) found evidence that natural scenes possess relaxing and restorative powers to human beings. Ulrich (1984, 1986) also found that exposure to natural scenes can reduce tension and anxiety. On the other hand, Bosselmann (1983a, b) and Linday (1978) concluded in their San Francisco and Seattle studies that exposure to sunlight is one of the critical factors in the success of design of an outdoor space. Leveratto (2002) remarked that existing open spaces are designed without including any climate considerations in Buenos Aires, Argentina. More recently, Thompson (2002) emphasized the importance of access to nature in urban open space design. The contact with nature is considered to have metaphysical or spiritual dimensions. Natural features, such as planting and sunlight, are therefore crucial to users of urban open space. 3.2. Analytic hierarchy process (AHP) Urban open space design evaluation is the measurement of the contribution of a multitude of factors to the achievement of a successful design. It involves a multiple criteria decision making (MCDM) process. In this study, we adopted the AHP which has been widely employed in many disciplines to deal with a decision making process characterized by a multitude of complementary and conflicting factors. The primary characteristic of AHP is the use of pair-wise comparisons. By using pair-wise comparisons, judges are not required to explicitly define a measurement scale for each attribute (Spires, 1991). Thus, the AHP is very useful for attributes that have non-linear importance of scale. The AHP was developed by Saaty (1980, 1982). It is designed to cope with both the qualitative and quantitative aspects of human thought in making multi-criteria decisions. The application of the AHP involves four major steps (Zahedi, 1989), namely: (1) breakdown the complex problem into a small number of decision criteria and then structure the criteria in a hierarchical form;

Urban open space design

607

608

MEQ 14,5

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U U

Table I. Design criteria for urban open space derived from literatures Pushkarev and Zupan (1975) Whyte (1980) Gehl (1987) Carr et al. (1992) Rubenstein (1992) Marcus and Francis (1990) Cherulnik (1993) U Tomalin (1998) U U U U U U U U U U U U U U

Location Size Visual complexity Amount of seating Seating materials Orientation of seating Sitting height Integral sitting Solar access Temperature Glare Wind Visibility Accessibility Planting Sculpture Fountain Paving Food Programs Safety Management Toilets

Cn C1

Main decision criteria Seating

Sni S11 S12 S13 S21 S22 S23 S24 S31 S32 S41 S42 S43

Decision sub-criteria Amount of seating Seating materials Orientation of seating Solar access Temperature Glare Wind Visibility Accessibility Planting Sculpture Fountain

Urban open space design

C2

Microclimate

609

C3 C4

Boundaries Landscape

Table II. Main and sub-design criteria adopted for urban open space design study

(2) make a series of pair-wise comparisons among the criteria according to a ratio scale of importance; (3) use the eigenvalue method to estimate the relative weights of the criteria; and (4) aggregate these relative weights and synthesize them for the final measurement of given decision alternatives. In our study, we breakdown the evaluation into a two-level decision hierarchy as shown in Table II. The first level consists of four main decision criteria, whereas the second level is composed of 12 sub-criteria. Pair-wise comparison involves comparing the criterion one by one in a specified scale of importance. The scale of importance used is shown in Table III. As an illustration, if the criterion “Seating” is regarded to be very strongly important compared with the criterion “Microclimate” in the evaluation of urban open space, then a “7” is inserted into the AHP pair-wise comparison matrix in Table III. The ExpertChoice (1998) software is used for the estimation of the relative weights of the criteria, thus the mathematical details behind are not elaborated. Interested readers may read Saaty (1980). 3.3. Data The sample of the study consists of 36 face-to-face questionnaire surveys on urban open space users in Hong Kong. The distribution of age, gender and education level of the respondents is summarized in Table IV. The response sample mainly consists of users aged between 15 and 24 and at tertiary education level or above. In this study, users are defined as those people who stay in an urban open space as distinguished from those who just walk through the plaza.

MEQ 14,5

Intensity of importance 1

Definition Equal importance Weak importance of one over another Essential and strong importance Very strong and demonstrated importance Absolute importance

Explanation Two criteria are of equal importance Experience and judgement slightly favour one criterion over another Experience and judgement strongly favour one criterion over another A criterion is strongly more important than the other The evidence favouring one criterion over another is of the highest possible order of affirmation When compromise is needed A reasonable assumption

610

3

5

7 9

2,4,6,8 Reciprocals of above non-zero

Intermediate values between adjacent scale values If criterion i has one of the above non-zero numbers assigned to it when compared with criterion j, then j has the reciprocal value when compared with i Seating 1 Microclimate 7 1

Boundaries 1

Landscape

Table III. AHP pair-wise comparison matrix for urban open space evaluation criteria

Seating Microclimate Boundaries Landscape

1

Source: Saaty (1980)

4. Results Table V presents the results of the survey. The global weights indicate the composite importance of each criterion. Figure 1 shows the weightings of the sub-criteria in descending order. The results show that microclimate is the most important criterion for urban open space users in Hong Kong. It is then followed by the criteria of landscape, seating and boundaries. Among the sub-criteria, planting far outweighs the importance of others. It reinforces the perception of the importance of microclimate as planting shares most of the functions in regulating microclimate of urban open space. Then criteria such as temperature, wind and solar access rank second to fourth on the importance rating. On the contrary, the material of seating, sculpture and fountain are the least three sub-criteria in assessing urban open space design from users’ point of view.

No of respondents Gender Male Female Age Below 15 15-24 25-44 45 or above Education level Primary school or below Secondary school Tertiary education or above 17 19 1 24 9 2 1 8 27

Percentage 47.2 52.8 2.8 66.7 25 5.6 2.8 22.2 75

Urban open space design

611

Table IV. Distribution of age, gender and education level of the respondents

Cn C1

Main decision criteria Seating

Weights 0.198

Eni E11 E12 E13 E21 E22 E23 E24 E31 E32 E41 E42 E43

Decision sub-criteria Amount of seating Seating materials Orientation of seating Solar access Temperature Glare Wind Visibility Accessibility Planting Sculpture Fountain

Global weights 0.064 0.047 0.086 0.099 0.110 0.063 0.102 0.061 0.090 0.163 0.055 0.060 Table V. Composite importance weightings for main and sub design criteria

C2

Microclimate

0.373

C3 C4

Boundaries Landscape

0.151 0.278

The findings reinforce the argument in many previous studies that natural features in urban open spaces are important to the users. It is especially true in Hong Kong, in light of the high density and high rise buildings environment. In fact, the area of urban open space per inhabitant in Hong Kong, which is about 2.9m2/inhabitant (Census and Statistics Department, 2001), is far below the international standard. The World Health Organization recommends 10m2/inhabitant, whereas in another big city, Buenos Aires, Argentina, provides 4.6m2/inhabitant (Leveratto, 2002). The findings imply that public spaces should not be designed as an isolated unit, but a creation of networks of urban space. As we found that people living and working in a compact city treasure urban spaces with plants, sunlight and wind. The designer has to consider the environment as a whole in order to optimize the natural lighting and ventilation to the open space. The

MEQ 14,5

612

Figure 1. Global weightings for sub-design criteria

accessibility of urban open spaces is also regarded as important since it forms a network of favoured routes which “influence how pleasant it can be to move from one area to another, how much daylight, landscape and beauty we can enjoy” (Rogers, 1999). The connection among open spaces can produce concerted effort in improving environmental quality. 5. Conclusions In line with Rogers’ (1999) contention that good design of urban space rests on the establishment of a direct relationship with people living and working around, we argue that users’ opinions on the design of urban space cannot be neglected in achieving a high environmental quality. We found that people in a compact city like Hong Kong put much emphasis on natural environment and comfort in the design of urban open spaces. Users’ opinions reflect the importance of planting, sunlight and wind in the design. The results strongly support that urban design should strike a balance between natural and man-made environment. People living and working in a high density and compact city would ask for open space with plants, sunlight and wind. However, the accessibility to natural sunlight and ventilation from the urban open space cannot be optimized without an integrated approach in the design. For example, an open space corridor which connects a series of open space would provide a skyline as well as a well-ventilated footpath. We further contend that a well integrated network of urban spaces with natural features, even small in size, is more appropriate than a few large but isolated open spaces in a highly compact city like Hong Kong. Owing to the

compactness of the city, it is very often more convenient to travel on foot instead of driving, if the air quality is good. However, when the design of urban space is not from an integrated approach, the network of urban spaces is not well connected, then people are forced to take some means of transportation. As a consequence, it further deteriorates the quality of environment. The importance of accessibility of urban open spaces in our findings reveals part of the contention. Yet, further studies are required to evaluate the importance of size and number of urban open spaces as well as their interrelationship.
References Bosselmann, P. (1983a), “Shadowboxing: keeping sunlight on Chinatown’s kids”, Landscape Architecture, Vol. 73, pp. 74-6. Bosselmann, P. (1983b), “Simulating the impacts of urban development”, Garten and Lanschaft, Vol. 93, pp. 636-40. Carr, S., Francis, M., Rivlin, L.G. and Stone, A.M. (1992), Public Space, Cambridge University Press, New York, NY. Census and Statistics Department (2001), Hong Kong 2001, HKSAR Printing Department, Hong Kong. Cherulnik, P.D. (1993), Applications of Environment-Behavior Research, Cambridge University Press, New York. NY. Corraliza, J. (2000), “Landscape and social identity: the construction of territorial identity” in, Proceedings of the 16th Conference of the International Association for People, Environmental Studies. Cullen, G. (1961), Townscape, Architectural Press, London. Eckbo, G. (1964), Urban Landscape Design, McGraw-Hill, New York, NY. ExpertChoice (1998), Team Expert Choice: Advanced Group Decision Support Software, ExpertChoice Inc. Friedmann, A., Zimring, C. and Zube, E. (1978), Environmental Design Evaluation, Plenum Press, New York, NY. Gehl, J. (1987), Life Between Buildings: Using Public Space, Van Nostrand Reinhold, New York, NY. Gibberd, F. (1967), Town Design, Praeger, New York. NY. Godbey, G., Graefe, A. and James, S.W. (1992), “The benefits of local recreation and park services”, in A Nationwide Study of the Perceptions of the American Public, Leisure Studies Programme, Pennsylvania State University for the National Recreation and Park Association, Pennsylvania, PA. Hartig, J., Mang, M. and Evans, G.W. (1997), “Restorative effects of natural environment experiences”, Environment and Behavior, Vol. 23, pp. 3-26. Jackson, J.B. (1985), “Vernacular space”, Texas Architect, Vol. 35 No. 2, pp. 58-61. Kaplan, R. (1982), “The green experience”, in Kaplan, S. and Kaplan, R. (Eds), Humanscape: Environment for People, Ulrich’s Books, Inc, Ann Arbor, MI. Kaplan, R. (1983), “The role of nature in the urban context”, in Altman, I. and Wohlwill, J. (Eds), Behavior and the Nature Environment, Plenum Press, New York, NY. Kaplan, R. (1985), “Nature at the doorstep: residential satisfaction and the nearby environment”, Journal of Architectural and Planning Research, Vol. 2, pp. 115-27.

Urban open space design

613

MEQ 14,5

614

Kaplan, R. and Kaplan, S. (1990), “Restorative experience: the healing power of nearby nature”, in Francis, M. and Hester, R. (Eds), The Meaning of Gardens, MIT Press, Cambridge. Leveratto, M.J. (2002), “Urban planning instruments to improve winter solar access in open public spaces”, Environmental Management & Health, Vol. 13 No. 4, pp. 366-72. Linday, N. (1978), “It all comes down to a comfortable place to sit and watch”, Landscape Architecture, Vol. 68 No. 6, pp. 492-7. Lynch, K. (1981), A Theory of Good City Form, MIT Press, Cambridge. Marcus, C.C. and Francis, C.A. (1990), People Places: Design Guidelines for Urban Open Space, Van Nostrand Reinhold, New York, NY. Milgram, S. (1970), “The experience of living in cities”, Science, Vol. 167, pp. 1461-8. Nager, A.R. and Wentworth, W.R. (1976), Bryant Park: A Comprehensive Evaluation of its Image and Use with Implications for Urban Open Spaces Design, Center for Environment & Behavior Studies, City University of New York, New York, NY. Parsons, R. (1991), “The potential influences of environmental perception on human health”, Journal of Environmental Psychology, Vol. 11, pp. 1-23. Pushkarev, B. and Zupan, J. (1975), Urban Space for Pedestrians, MIT Press, Cambridge. Rogers, R. (1999), “Towards an urban renaissance: final report of the urban task force”, Chaired by Lord Rogers of Riverside, Department of the Environment, Transport and the Regions, London. Rowe, C. and Koetter, F. (1978), Collage City, Mit Press, Cambridge. Rubenstein, H.M. (1992), Pedestrian Malls, Streetscapes, and Urban Spaces, John Wiley & Sons, New York, NY. Saaty, T.L. (1980), The Analytic Process: Planning, Priority Setting, Resources Allocation, McGraw-Hill, London. Saaty, T.L. (1982), Decision Making for Leaders, Lifetime Learning Publications, Belmont, CA. Spires, E.E. (1991), “Using the analytic hierarchy process to analyze multiattribute decisions”, Multivariate Behavioural Research, Vol. 26 No. 2, pp. 345-61. Tandy, C. (1972), “Handbook of urban landscape”, in Architects’ Journal, Technical Section, Architectural Press, London. Thompson, C.W. (2002), “Urban open space in the 21st century”, Landscape and Urban Planning, Vol. 60, pp. 59-72. Tomalin, C. (1998), “Urban spaces in town centres: a route to success?”, Built-Environment, Vol. 24 No. 1, pp. 35-6. Ulrich, R.S. (1984), “View through a window may influence recovery from surgery”, Science, Vol. 224, pp. 420-1. Ulrich, R.S. (1986), “Human response to vegetation and landscapes”, Landscape and Urban Planning, Vol. 13, pp. 29-44. Wachs, J. (1979), “Primal experiences and early cognitive intellectual development”, Merrill-Palmer Quarterly, Vol. 25, pp. 3-42. Whyte, W.H. (1980), The Social Life of Small Urban Spaces, Conservation Foundation, Washington, DC. Worpole, K. (2000), “Regaining an interior world”, Landscape Design, Vol. 289, pp. 20-2. Zahedi, F. (1989), “The analytic process – a survey of the method and its applications”, Interfaces, July-August, pp. 96-108.

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close