Sustainable Arabic Urban Design at Neighborhood Scale, a Morphological Approach
Serge Salat
Urban Morphology Lab
Sustainable Architecture and Urban Development, Amman, 2010
Abstract
The paper is based upon a quantified analysis of the built and empty spaces configuration and composition, shapes and patterns, in different Arabic cities. The paper analyzes traditional Arabic neighborhood morphology in the Mediterranean region with an approach based on urban metrics, street patterns analysis and fractal complexity. By 2030 the Mediterranean cities will count 100 million new inhabitants mostly in the Arabic world. This new urbanization will have to meet with the challenge of sustainable development and with a more and more arid climatic situation due to Global Warming. On the other hand, the Arabic architecture and groups of building layout present a huge potential for solar energy and have a long tradition of bioclimatic urbanism with a skilful use of narrow and high winding streets, inner courtyards as well as water, trees and light filters. We analyze urban morphology in the Arabic context, as morphology alone is an influential factor on the energy performance and livability of a city that can halve by itself the energy needs. We question what social, spatial and bioclimatic lessons are to be learned from historic Arabic cities (medinas) for the design of contemporary neighborhoods in the Arabic region and what is the specific identity of an Arabic sustainable neighborhood.
Introduction
Whereas in Europe urban morphology of cities changed slightly along time for centuries, the South of the Mediterranean Sea experienced a huge morphological discontinuity between the colonization and the creation of new cities as in Morocco. Barcelona is a typical example of a smooth change in its urban morphology between the old, medieval Barri Gothic and the new, modern extension designed by Cerda during the 19th century. In Sfax, the old medieval city (the medina) is closed by high walls. The French created a new regular gridded city adjacent to the medina with typical French urbanism.Today, both North and South shores of the Mediterranean Sea are experiencing a new morphological change with the international car driven modern urbanism inherited by Le Corbusier’s theories. The new morphologies are characterized by high-rise buildings with no connection to their environment, and urban sprawl. With the same population (2.1 million) the Great Tunis is 25 times bigger than Paris. These new forms of urban growth have potentially disastrous effects on energy consumption of Arabic cities and are not socially integrative.
1. METHODOLOGY
The Urban Morphology Lab has developed an innovative approach using metric tools to analyze cities’ urban fabric. It can thus deal with the consequences of urbanism in terms of energy use and of way of living.The lab works with geometric shape factors composed of heights, lengths, depths of elements of the town (streets, squares, buildings, blocks…), and fractal shape factors to measure more complex objects such as the boundaries of the city. This shape factor approach is completed by a graph analysis of street patterns distinguishing between the constitution, the configuration and the composition of the connecting layout of the city. The human activities layer is added through an accessible density and diversity analysis based on the theory of information and the Shannon formula (mathematical formula quantifying the mean content in information of a set of messages). This innovative scientific approach using complementary metric tools to analyze cities’ urban structure and fabric as well as related human activities at various scales, can predict the energy consequences of critical choices of city form at the planning stage or can assess existing cities for carbon plans. Urban metrics provides a structure and an order able to clarify complex urban problems, and helps finding solutions in bioclimatic, energetic but also social and economic topics. For each specific study, metrics results are read into the cultural uniqueness of the site.
Twenty five cities have already been studied thanks to this method such as Paris, Shanghai, Guangzhou, Hong Kong, New York, Kyoto, Tokyo, Chandigarh, Brasilia, New York, Washington, Barcelona, Turin, Toledo, Rabat, Fez … It has helped bring to attention tendencies and create a typology of neighborhoods showing morphological characteristics bound to energy performance. Among them, the Arabic historic neighborhoods have a distinctive morphology and identity.
Urban Morphology is a discipline focusing on the composition of Urban Fabric. The city can be seen as a superposition of 6 layers. Each one can be studied separately to have a better understanding of the city as a whole.
• Level one comprises human beings and activities. The interactions between people are the first factor of organization of a city. In fact, towns are places of maximization of exchanges and interactions of all types between persons.
• Level two is the street network. It was initially created by the real journeys made the most often by the inhabitants. But today, it is too often decided by engineers almost arbitrarily. Streets networks are a facility but also a constraint which forces the inhabitants to follow one way to go to one point and can incite them to use some transport modes. • Level three is the study of parcels. Historic and administrative organization is a constraint encouraging some forms of building. When parcels are small, it is difficult to build giant towers, and the territory is more resilient to change. On the contrary, large parcels allow for big buildings and a lot of empty space on the ground.
• Level four is the topography and relief of the site, which is an obvious constraint, but also something with which architects and urban planners can play.
• Level five is land use and repartition of activities. It affects people flows, housing allocation, and has an economic and social importance. It also determines the energy spent in transport.
• Level six shows the three dimensions of the city. The solids and the empty spaces determine the air flow and the sun penetration, and therefore the dispersion of pollutants and the temperature of the city.
The data are used to construct urban parameters that affect energy consumption and environmental performance. We can compare the performances of cities across the world by integrating their morphological parameters into energy and environmental equations, in order to help decision-makers organize cities so they consume the fewest resources possible while remaining attractive places to live. Acting simultaneously on urban form, building technology and systems, and people’s behaviour would help reduce GHG emissions in successive, cumulative steps. By itself, well-thought-out bioclimatic design of urban morphology would cut GHG emissions in half. Optimizing building technology would further divide emissions by 2.5, while optimizing systems would halve them again. Finally, residents adopting “sober” or low-carbon-consuming behaviours would again divide energy consumption by 2.5. Ultimately, combining all of these factors would have a multiplicative effect, reducing energy consumption by 90% to 95%.
2. THE CLASSICAL ARABIC CITIES
The centre of the classical Arabic city (the medina ) is the site of the Friday Mosque – the jami – an empty focus of the religious significance of the city. This unique centre, symbolizing the divine Oneness, lends meaning to the medina as a whole, and structures the town’s religious and commercial activities. The souks encircle the jami in such a way that the shops built hard against the walls of the mosque completely mask its presence. Having no façade to speak of it literally disappears from view, and only the minaret is there to hint at its presence. The Friday Mosque is the invisible heart of the medina. That the centre of the town is quite empty is attested by the courtyard of the Mosque – an “absent” monument around which the noblest commercial activities are located. This central invisible hollow presence of the Mosque is topological not geometric.
The creation of a perimeter wall around the medina dates from the foundation of the Mosque. Two acts constituted the founding of the city: the definition of an area in contrast to the surrounding countryside, and that of an inner sanctum for the construction of the Great Mosque. This opposition between a single centre and a linear perimeter forms the basis of the medina’s primary structure: the relationship between the centre and the periphery regulates the city’s internal functions and determines the positioning of the different economic and cultural agents within it. At some distance from the central souks, the residential quarters form a homogeneous continuous fabric within the medina. The housing blocks of the medina are formed by a gradual and homogeneous additive process based on a single type: the courtyard house. The houses are situated as far as possible from the centers of public and commercial activity, at the heart of the blocks located at the ends of cul-de-sacs.
Several important facts emerge from this description:
1. A continuous typology and modularity unifies all the urban fabric: the courtyard building
2. Whatever their class, the buildings were not so much defined by external geometric features but by topological properties with a positive emphasis put on interiority.
3.The lines of access to the houses (thoroughfares, secondary streets, cul-de-sacs) follow upon the placing of buildings instead of the building site coming into existence from the street plan, as in the European city
4. Once the Mosque, the perimeter walls, the thoroughfares and the souks had been positioned the city was founded and then grew incrementally following a bottom up process.
3. THE SPECIFIC CONNECTIVITY OF THE ARABIC CITY
We will analyze in this section the connectivity of the city using the graph theory. We will evaluate the number and quality of connections in typical Arabic street patterns and compare them to non-Arabic patterns in order to assess the uniqueness of the Arabic urban networks. We will show through this rigorous quantifiable topology approach, that Islamic street patterns share distinctive features, which make them different from any other patterns and which can be expressed with a separation function between Islamic and non-Islamic street patterns.
This Google image of Sfax medina in Tunisia shows the dramatic change in street patterns and in the urban grid size between the historic Arabic city and the present road system. The fine grain of street patterns of the medina is circled by huge car roads. While the medina was a walkable city, it is now surrounded by a sprawled car city. Tunis, Sfax and other Maghreb cities have become a fragmented collage of urban fabrics. Restoring the continuity of the urban fabric has become an issue for the south Mediterranean city. To achieve continuity, a metric and space syntax analysis of the existing street patterns is necessary. This is the task currently undertaken by the Urban Morphology Lab.
3.1 Our approach
The Urban Morphology Lab uses mathematical theories, like the graph theory, to analyze different urban textures and their connectivity. In order to analyze street patterns, three levels of analysis must be distinguished with different degrees of abstraction. • Composition of the street network. This is the first impression anyone has, when he comes into a new city. The connection between the human being and its environment are the core part of the composition: how does the space physically or visually impact the man? For example, to describe the medina the narrowness of streets, the relative heights of buildings, the impression of surprise created by the sudden discovery of small triangular places around the corner of a small street, must be discussed on a composition point of view. Composition can be described by shape factors, for example the ratio between the height and the width of the street, which in a medina can be as high as 14 like in the narrow streets of Fes.
• Configuration. The form is taken out of the analysis and the focus is put only on topologies, that is to say the connections between the different elements of the city. Ratios are calculated, indicators of continuity and connectivity.
• Constitution. The structure of links and nodes is then the center of focus. Hierarchy and constraints are the two central topics discussed in this part. Typologies of street patterns are built and used. This part helps to understand the fundamental choices of urban designers.
Our approach implies the definition of indicators, such as the cyclomatic number. Cyclomatic numbers, which count the number of circuits in a network, prove very useful to measure a city’s degree of connectivity based simply on its block organization. A cyclomatic number gives us an idea of the number of possible routes between one point to another: the higher the cyclomatic number is, the more diversified the possible routes and the less congested the city will be. Moreover, route diversity allows various forms of transport – such as walking, bicycling, or taking the bus or tram – adapted to different activities. The cyclomatic number, combined with the average distance between two intersections, has been used by the Urban Morphology Lab to study several cities in different regions of the world, allowing comparisons of their urban block forms.
The Urban Morphology Lab studies showed that historic urban forms, such as those in the historical centre of Kyoto, or in Paris, have many more alternative routes and much shorter distances between intersections than modern tower-block cities, such as Le Corbusier modernist archetype City of 3 Million inhabitants. The first two cities have layouts that allow movements on foot or by bicycle, subsequently adapted to trams. Both cities were built before motorized vehicles, while modernist cities develop solely to suit the needs of cars. This clearly creates problems: cars tend to exclude other people, occupy a great deal of space and concentrate high pollution levels. A sustainable city must allow individuals to choose their transport modes and to adapt them to their activities, giving priority to soft, non-polluting means of transport – means that are more beneficial to health, accessible to all types of people, and independent of unproven and costly technological advances intended for less-polluting cars. A sustainable city must allow individuals to choose their means of transport.
3.2 Measuring the connectivity of Mediterranean urban forms: the example of Fes, Morocco
Islamic patterns can easily be set apart from other patterns. Moreover these specificities can be mathematically analyzed. That is the object of the very interesting work of Kubat & Asami, who created a mathematical function to discriminate Islamic patterns. Their work outlined the following characteristics of Islamic patterns:
– Numerous cul-de-sacs
– Many T-junctions
– Few X-junctions
– Narrow and curved streets
– An opaque network that cannot be apprehended totally easily.
This Arabic street pattern is hierarchical. The main thoroughfares and secondary streets are reserved for trading activities, public buildings and amenities; they constitute the main arteries of the medina. The narrower side streets and cul-de-sacs, whose essential role is to provide access to the houses, are perpendicular to the thoroughfares and secondary streets, their private aspect creates a strong contrast with the principal streets. The groups of houses hemmed in the side streets constitute blocks to which access is provided by cul-de-sacs leading to the houses. The layout of these blocks is informal, and their size can vary greatly in length and depth – in fact they are conglomerates characterized by irregularity and the absence of geometrical form.
Traditional Islamic patterns are characterized by a very thin grain of the urban grid. The enlargement of urban grid patterns is one of the main transformations of Mediterranean cities. We applied our metrical method to four samples of urban morphologies in Fes, Morocco.
The mean distance between intersections is 10 meters in Fez medina, 40 meters in Toledo and almost all European medieval cities, which are very close to the medina type, whereas the mean distance between intersections is 150 meters in Paris, Melbourne and Hong Kong. It is a first morphological difference in the urban form, from the medieval type, with a very thin grid, and the European mid XIX th century grid. However, the colonial European cities built in Maghreb are based on a fine grid of approximately the same size as the historic Islamic one (about 50 meters). In this sense the colonial extensions of the Arabic historical city fabric replace the focus on interiority by external façades and the maze of Islamic patterns by a rectangular grid, but they respect the grain of the city while transforming deeply its shape (from irregular to regular) and topology (from complex and folded inwards to simple and outwards). Then another huge morphological change appeared in the second half of the 20th century in Europe and more recently in Arabic countries with the new modernist urban forms and the urban sprawl. The distance between intersections in Le Corbusier city of 3 Million inhabitants, which is the prototype of this urbanism and in Brasilia it is 400 meters. We can find this kind of typology in Fes and all over the south of Mediterranean, with old medinas, colonial towns, and new developments.
This multiplication by more than ten of the city basic grain size, creates a city made for the car and not for the pedestrian. It produces a city, which doesn’t reach the density required to protect itself from the sun through the clumping of housing units with each other. The cyclomatic number is also very important. It is an indicator of the number of different possible paths through the city. The cyclomatic number is crashing down in the modern town, creating a monotonous repetitive city from a pedestrian point of view.
4. THE COMPLEXITY OF THE ARABIC CITY
The Arabic classical city was a mixture of organic growth and of preconception in the placement of the founding Mosque end perimeter walls. It is possible to demonstrate by using the theory of information that it was maximizing the number of complementary connections in a highly differentiated society. Nikos Salingaros as shown that the living and resilient city is the one who maximizes redundant connections. This structural very high number of connections is an explanation of the extraordinary resilience of the urban form of Maghreb Islamic medinas, which have existed for 1300 years trough various invasions and changes of power. Their fabric was complex, folded around invisible interiors, which could be reached only through several enclosing boundaries, and by crossing the skifa, the zig-zagged entrance hall. These zig-zagged patterns characterize not only the house entrance but virtually all passages in Arabic towns.
The residential areas while looking informal in fact logically clustered. At first they might seem to exist in some form of cellular accretion, with the house being the unit of growth, located as close to the outermost existing house as building techniques would permit. Interstitial space would be private, or at least excessively parochial, and spatially minimal. Narrow paths between buildings would suffice, and their direction could be determined by the needs of the immediately adjacent residents. In reality this apparently informal structure has a complex order reflecting the social segmentation of Arabic societies. In cities like Toledo where, after 1492, the Christians have created a new order on the underlying basis of the formerly Islamic city, the maze qualities of the city have much more intensified, while in Arabic cities the spatial lecture of the city as remained quite simpler to understand. In this sense, the complexity of Toledo is much higher than the complexity of the classical medina.
Nevertheless, organic medieval Mediterranean cities share the complexity of the maze inherited from archaic Athens. The result of the aggregative growth was the residential maze we read of in the sociological and defensive justifications. According to Lavedan, Aristotle tells us that the narrow and tortuous streets of Athens were an enigma deceiving to strangers and a labyrinth dangerous to enemies (Lavedan 1926 1: 115-15).
Due to this maze quality the classical Arabic city is designed to maximize complexity and connections. It might be compared to the Roman city and to the Modernist city. For the Roman city, we will take the example of the center of Torino based on a Roman layout; for the Modernist, we will take Le Corbusier archetype of City of 3 Million inhabitants: and for an Arabic city, the medina of Sfax in Tunisia.
One of the striking morphological changes in the Arabic world is the recent modernist mega projects. They result not only in a loss of identity and connectivity, but also in a loss in complexity and social order. The claim that the towers are vertical streets needs to be challenged. Streets offer shops, open spaces and places for meeting, strolling and relaxing. In very tall towers, elevators are needed to take people from one place to another. Circulation in such a context necessarily involves a destination – a beginning and an end – which leaves little room for the changing paces, movements and spur of the moment shifts in direction that characterize human circulation. Streets are places of meeting and exchange. They are public spaces.
In actual fact, these towers do not replace the streets but rather groups of urban blocks comprising many streets. The analysis can and must be conducted comparing towers to the urban fabrics that they replace. For this purpose, it is interesting to compare four Le Corbusier towers placed on a square of 800 meters between axes and the center of Turin corresponding to the layout of the Roman city covering 710 by 770 meters.
In Turin, nearly all the ground floors are occupied by shops and the linear length of the façades facing the street is significant: nearly 30 km in the square of 800 meters being studied as against 0 in the Le Corbusier district. The linear length of façades facing the courtyards is also quite significant: 16 kilometers as against 0 in the Radiant City. The street in Turin is a place of intensive exchange, commerce and human activity. In a natural way, this type of street life creates social bonds that contribute to a better quality of life, unlike modernist forms that dehumanize streets, eliminating the human factor and giving pride of place to cars. Courtyards are semi-private, open spaces that are reassuring by their human scale and that lend themselves to interactions between residents – exactly the opposite of the oversized and disquieting empty spaces in the Radiant City from which courtyards have been eliminated. Topologically, Corbusian streets are a series of dead-ends without the slightest human interface. An extremely rich model, architecturally and socially, was replaced by a monotonous organization that breaks down social bonds.
As we see on the plans at the same scale, the entire Sfax medina is replaced in Corbusian modernist urban schemes by a single skyscraper surrounded by highways, with a considerable loss of complexity. In the medina, which measures 400 meters by 600 meters, the porous texture of 100 courtyards develops 2 km of façades around courtyards. The number of urban blocks is 104. With the cul-desac the average distance between intersections is 10 meters, hence creating a very fine grain city fabric. The length of streets is 11 km, which creates 22 km of facades on courtyards.
If we extrapolate for the sake of comparison the Sfax medina figures to a sample of 800 meters by 800 meters of a larger similar medina, such as the one in Tunisia, we find striking results. In a sample of 800 meters by 800 meters of medina urban fabric:
1. The number of blocks is 270 in Arabic urban fabric to 68 in Turin and only 4 in Le Corbusier modernist scheme. As the cyclomatic number is correlated to the number of blocks. That means that the diversity of routes is 68 times higher in a medina than in a modernist scheme and 4 times higher than in a roman scheme. If we compare the medina with the European extensions of the colonial period (average number of blocks on a 800 meters site: 196) we see that the cyclomatic number in a medina is only 40 to 50 % higher than in the European extension. This confirms our previous remark about the continuity in complexity between the medina and the colonial extensions of the XIX th century and the present collapse in complexity and compactness of the city fabric.
2. The linear development of facades on courtyards is 5.4 km in a medina, that is 4 times less than in Turin due to the small size of the courtyards, which are private. But the striking result is the street facades, whose linear development is 60 km in a medina compared to 30 km in Turin and 0 in Le Corbusier City of 3 million inhabitants. Although the Arabic house is turned onwards, the absolute record in terms of street length shows that far from being just residual the street connective network is probably the most striking feature of the classical Arabic city.
5. URBAN DENSITY
With 2 habitable floors, and a plot coverage ratio of 72 % the medina of Marrakesh urban fabric has a plot ratio of 1.43 superior to modern urban developments in Europe. Our studies on Rabat Sale recent urban fabric show lower or comparable densities without a significant increase in density in planned neighborhoods. Only informal settlements have a superior density. An ongoing project of the Urban Morphology Lab is to make a benchmark of densities of all types of urban fabric in the Mediterranean area, which will be published in a subsequent article.
6. MICROCLIMATE AND BIOCLIMATIC POTENTIAL
6.1 Introduction
Current design guidelines used in Northern Europe do not apply to the Southern shore of the Mediterranean Sea, where the main question is to deal with a hot and dry climate. Lessons for the design of urban forms can be found in traditional organization of human settlements, which were very efficient to protect from light and to use wind to refresh the city at different scales thanks to a very porous urban texture (with the traditional courthouse) which creates a dense but porous and breathing city. This peculiar texture manipulates the climate to create a more livable and sustainable city, and it could be used to design new urban developments. The ancient Greeks, as well as Mesopotamians and Egyptians, designed their towns as tools able to organize symbiotic exchanges with their environment.
6.2 Greek and Roman development of the “bioclimatic housing” concept
In Greece, it was above all the Economics by Xenophon (born around 340 BC) that led to the birth of “bioclimatic housing”. He saw the need to orient buildings and make nature and land bend to production requirements while continuing to respect their natural characteristics and potential. Around 350 BC, Aristotle made a number of observations concerning the relationship between the healthiness of the air and the prevailing winds, reconciling the need of defense and harmony with nature. One of the most important treatises by Hippocrates, Treatise on air, water and places, formulated basic public hygiene concepts linked to the choice of where to build and urban planning. These characteristics continue to remain strongly anchored in innumerable examples of ancient architecture and in today’s towns around the Mediterranean Sea. Given that they were designed to provide a maximum level of comfort in a world without fossil fuels, they provide examples of complete urban complexes based on zero energy bioclimatic urban morphologies.
6.3 The sustainable Arabic town is a complete and organic bioclimatic unit
The organic functioning of the historic Arabic towns results in the creation of informally shaped built masses that provide an unbroken continuity between the houses. Each housing unit is organically connected to its neighbors, resulting in an air filtered by the preceding houses being introduced to circulate through the rooms and beyond. The formal consequence of this bioclimatic orientation is that the urban grid is given a unitary appearance: houses interpenetrate like organic cells, creating a dense, porous tight fabric amalgamated by its own heterogeneity. The urban layout of the medinas gives them the appearance of being a single large structure. The widths of the streets are designed to prevent the walls of the houses from overheating during the summer. As in many other old Mediterranean cities, bioclimatic design underlines the construction of the urban groupings of medinas. The relationship between the urban morphology and the sun, wind and the use of local materials, the interaction of the houses with the ground and the urban morphology results from an attentive design approach that has always been closely linked to local environmental resources.
6.4 The historic Arabic bioclimatic town is naturally cooled without any energy cost.
The houses are equipped with underground air conditioning, as each house has “roots” in the basement formed by small rooms and equipped with a well in which rainwater is stored. These cavities, which create an environment where the temperature remains cool and constant throughout the year, have connecting passageways leading to the house’s upper levels. The higher temperature of the rooms resulting from the daily sunlight sets an internal ventilation level thanks to exchanges with the air currents provided from the underground chambers. The cooling is based on three physical laws: – the natural thermal inertia and insulating quality of the walls, – the heat exchange between water and air, – the slow endothermic evaporation of the water. This process is able to maintain the temperature of the environment and the air at a satisfactory level throughout most of the year without any energy cost: during the winter, the high thermal inertia of the thick walls retains the heat while, in the summer, it cools the rooms. This phenomenon is facilitated by the natural movement of the air inside the house. In harmony with Mediterranean traditions, the external skin of the buildings also has an influence on the climate of the rooms in the house. The white colors form a sort of skin that protects the architecture from extremely high and low temperatures.
6.5 The solar and photovoltaic potential of courtyard houses
In the framework of the ZED project (Towards Zero Emission Urban Development) the Martin Centre for Architectural and Urban Studies of the University of Cambridge and other partners have assessed the solar potential of 6 generic urban forms including courtyard blocks. This study has been done in the London climate and for European forms. A project of the Urban Morphology Lab is to renew this study in the Mediterranean climate with generic archetypes of actual forms of Mediterranean cities. The solar radiation analysis performed by Cambridge show already that the courtyard form is particularly suitable when considering solar collection on the roof, for example with photovoltaic panels. The fact that it receives the least radiation on vertical surfaces further suggests its suitability for hot climate, as a way of minimizing solar gain through facades. This strategy is exemplified by vernacular architecture in hot desert regions, where the courtyard is a recurring feature.
CONCLUSION
This analysis aim at encouraging new researches and quantitative evaluations to invent new urban forms as sustainable as the old medina, but suited to the modern way of life and which can cope with the 100 billions new inhabitants in the Mediterranean area.
The specific Arabic features (density/compactness, connectivity, fractal complexity) have a huge impact on sun, wind and light penetration in the urban texture and on the energy efficiency of the city by creating a porous texture with a high level of complexity and an ability to manipulate the climate at different scales. For example, the air temperature increases while the density decreases and the humidity increases with the density. As Arabic vernacular architecture is more sustainable and climate sound in the Mediterranean region, more adapted to cultural behavior and less expensive than current technological approaches to sustainability mainly developed in the northern cold climates, the conclusion of the paper is that we can use some characteristics of Arabic traditional neighborhood patterns and adapt them to built modern sustainable neighborhoods affordable to all in the Arabic region.
REFERENCES
Adolphe, L. (2001) A Simplified Model of Urban Morphology: Application to an Analysis of the Environmental Performance of Cities. Environment and Planning B: Planning and Design, 28(2), 183-200.
Ali-Toudert, F. and Mayer, H. (2006) Numerical Study on the Effects of Aspect Ratio and Orientation of an Urban Street Canyon on Outdoor Thermal Comfort in Hot and Dry Climate. Building and Environment, 41(2).
Arnfield, A. J. (1990) “Street Design and Urban Canyon Solar Access.” Energy and Buildings, 14 (2), 117-131.
Brown, G. Z. and Dekay, M. W. (2001) Sun, Wind and Light: Architectural Design Strategies. New York: John Wiley and Sons.
Brunner, C. and F. Roustan (Eds.) (2005) Densité et formes urbaines dans la métropole marseillaise, Marseille: Imbernon.
Cheng, V., Steemers, K., Montavon, M. and Compagnon, R. (2006) Urban Form, Density and Solar Potential, Proceedings from the 23rd Conference on PLEA. 1- 6 September..
Compagnon, R. (2004) Solar and Daylight Availability in the Urban Fabric. Energy and Buildings, 36(4), 321-328.
Gallotti J. (1926), Le jardin et la maison arabes au Maroc, Actes Sud, Paris Givoni, B. (1989) Urban Design in Different Climates. World Meteorological Organisation. 346.
Golany, G. S. (1996) Urban Design Morphology and Thermal Performance. Atmospheric Environment, 30(3), 455-465.
Groleau, D. and Marenne, C. (1995) Environmental Specificities of the Urban Built Forms, Rebuild-Rebuilding the European City. Integration of Renewable Energies in Established Urban Structures, Corfu, June-July.
James, E. and Vance, JR. (1990) The Continuing City, Te John Hopkins University Press, Baltimore Kubat & Asami, Characterization of Street Networks in Turkish-Islamic Urban Form, Proceedings, 3rd International Space Syntax Symposium Atlanta 2001
Lavedan, P. (1926) Histoire de l’urbanisme : Antiquité-moyen age, Henri Laurens, Paris, 1:114-15 Marchal, S. (2005) Street and Patterns, Spon Press, Abingdon
Mills, G. (1999) Urban Climatology and Urban Design. 15th ICB and ICUC, Sydney, 8-12 November.
Oke, T. R. (1988) Street Design and Urban Canopy Layer Climate. Energy and Buildings, 11(1-3), 103-113.
Okeil, A. (2004) In Search for Energy Efficient Urban Forms: The Residential Solar Block, The 5th International Conference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings Proceedings, Toronto, May.
Olgyay, V. (1963) Design With Climate: Bioclimatic Approach to Architectural Regionalism, Princeton, NJ: Princeton University Press.
Ratti, C. and Richens, P. (2004) Raster Analysis of Urban Form, Environment and Planning B: Planning and Design, 31(2), 297-309.
Ratti, C., Baker, N. and Steemers, K. (2005) Energy Consumption and Urban Texture, Energy and Buildings, 37 (7), 762-776.
Ratti, C., Raydan, D. and Steemers, K. (2003) “Building Form and Environmental Performance: Archetypes, Analysis and an Arid Climate”, Energy and Buildings, 35 (1), 49-59.
Salat, S. (2009) “Energy Loads, CO2 Emissions and Building Stocks: Morphologies, Typologies, Energy Systems and Behaviour”, Building Research and Information, 37 (5-6), September, 598-609.
Salingaros, N. (2005) Principles of Urban Structure, Techne Press, Netherland
Santelli, S. (1992) Medinas, Dar Ashraf Editions, Tunis