Impact of Urban Open Spaces on City Spatial Structure (In Case of Isfahan)

Abstract

Public spaces can be considered as important elements to improve the quality of the environment and increase the sense of citizenship. On the other hand, the cohesive network of urban spaces shows the integrated structure of a city’s spatial organization, in which not only the connection of form and function is considered, but also meaning finds its place in a complex urban system. Since the spatial structure of the traditional Iranian cities is ingrained in geographical factors and culture of the settlements, the evolution of this structure in Isfahan as one of the most famous historical cities in Iran is examined. The aim of this study is to answer this question: How do urban open spaces impact city spatial structure? The research method is descriptive-analytical, which has been concluded in a process of content analysis. The development of Isfahan’s structure over time and role of urban spaces in its formation has been studied. Entrances, key points, roads, and water edges as main urban spaces impact on city structure direction. The structure has changed from linear-nuclei to central-radial and finally, an integrated network to the Safavid era, but cohesive nature of the structure has changed from the Pahlavi period with multiple sections of streets.

1. Introduction

Looking at city structures, both open and closed parts are considered to form the shape of a city. Therefore, cities are not just about masses and not mere open lands but the combination of these two make the city structure, which differs in different regions based on so many factors.

The structure of traditional Iranian cities has a special physical-spatial cohesion and order that is guaranteed by their richness and physical quality. One of the most important features is the continuity of the city and neighborhoods through the centers, main passages, and the bazaar, which has led to the formation of a clear and legible structure in the city and the continuity of components and elements of the city. The composition and construction of the city in the past of Iran have been such that the main passages and the bazaar have been responsible for the connection between the important elements of the city.

However, since the first years of the present century, when the street has emerged as the dominant and decisive element in the city, urban cohesion has undergone serious changes. The street runs through the city, presenting itself as the powerful lips within the city, and from the integrated structure of traditional cities, only residential contexts remain, such as islands cut off from the arteries of urban life. At the same time, the spaces and elements of the communication network must establish an organized and regular relationship with the components and structures of the city and the current activities in it. Because the formation of urban spaces and elements along the roads is influenced by the behavioral patterns, culture of the people, and the economy of the society [1].

In contrast to the modern Iranian series, which are simply copies of the contemporary diffused European and American cities, the traditional Iranian city is concentrated and how much genius in its buildings combining diverse land uses in a tight relationship with each other. In this way, three main factors affecting the early compact Iranian cities may have been the physical environment of the Iranian plateau, trade and historical events, and the socio-political structure of the country [2].

One of the important but forgotten elements affecting traditional cities is urban open spaces formed among the compact masses of buildings. Therefore, this research is an attempt to investigate influential factors on city structures and identify the role of open spaces on spatial city organization. In traditional Iranian cities, the urban structure was based on the geographic characteristic of the surrounded environment. Since a vast area of this country is covered with desert and hot and arid climate, cities were shaped in a very compact and dense form. Besides the central courtyard of individual buildings, urban open spaces emerged as a joint element among the masses. On the basis of the carried out research, the paper analyses the historical development of Isfahan as one of the historical cities of Iran with a very compact context affected by geographical conditions, while urban open spaces still emerged as key elements in a very unique form.

2. City structure

The Latin root of the word structure “struere” means to build, grow, and evolve. Hence, the structure means “working together continuously to evolve.” For example, living features grow and evolve in a continuous, purposeful, and highly organized movement. In this way, each structure has its own function and shape, which plays an important role in facilitating the function of the structure [3].

The structure is a complete set of relationships in which the elements may change but remain dependent on the whole and retain their meaning. The whole is independent of its relations with the elements. The relationships between the elements are more important than the elements themselves. Elements are interchangeable, but relationships are not [4].

Against the views of those who believe that structures are formed based on functions and goals, there is also the opinion that structure is determined by its elements and their combined features, regardless of the specific function and purpose [5]. The structure is a set of interdependent processes and interrelationships of elements or a network of relationships between elements’ positions that are plotted within the external appearance of the object, the shape [6].

Some believe that the structure is made by the human mind and then projected onto the shape of the city. Researchers seek to discover the subconscious mind structures that are common to all societies. The latter group aims to find the relations and rules that have been effective in the formation of these structures to use them in the emergence of subsequent structures [7].

From all these definitions, it can be concluded that structure is a set of interdependent elements, in which the necessary and simultaneous mutual relations or partnerships between components take place abstractly and objectively and depending on the purpose, within a certain range.

The spatial structure of the city shows the order and the relationship between the physical elements and the uses in the city [8]. In other words, the spatial structure refers to a set of communications resulting from the urban form and the gathering of people, the transportation and flow of goods and information [9]. Alain Bertaud combines the spatial structure of a city into two components, namely the spatial distribution of population and the pattern of people’s travel from where they live to the various destinations and places, where an important social activity or interaction takes place, such as the workplace, and knows the location of social gatherings [10].

Therefore, city structure includes various elements coming together creating a city with its own characteristic. These elements not only work individually but also generate unity resulting in a homogenous city structure. It does not matter if it is open or close space, but it is important to form in a way that integrates the whole structure. However, urban open spaces are dominant features reflecting the story of the city and residents’ culture and lifestyle.

3. Urban open spaces

Open space, on the one hand, refers to a space that is relatively open, less closed, and has more limited space, and on the other hand, refers to a space opened by the masses to the majority of people. This refers not only to landscapes, such as parks and green spaces but also to streets, squares, alleys, and courtyards [11].

“If we want to clarify the concept of urban space without imposing aesthetic criteria, we have to consider the spaces between buildings in cities and other places as urban space,” says Rob Carrier. This space is geometrically surrounded by various symbols. Only the clarity of its geometric features and esthetic qualities allows us to consciously consider the outdoor space as an urban space. Outdoor open space is defined for outdoor mobility and is divided into public, semi-public, and private [12].

Zucker considers urban space to be an organized, neat, and orderly structure physically for human activities and based on specific and clear rules; These rules are: the relationship between the shape and the body of the buildings enclosing the same shape and uniformity, with their diversity, the absolute dimensions of the bodies to the width and length of the space between them, and the angle of passages or streets to the square, and finally the location of historical monuments, fountains, and slabs or other three-dimensional elements that can be emphasized [13].

Bruno Zevi considers space to be the essence of architecture, and follows the same definition of urban space, stating that streets, squares, parks, playgrounds, and gardens are all empty spaces that are limited or defined as space [14].

Urban space in a general sense is a kind of interrelation between relationships and behaviors, while the place is adjacent to individual identities, in urban life, it is the most important factor of authentication and affects human behaviors. In addition, urban space, as a public area, is the place of emergence and revitalization of individual and social thoughts and desires, which is why it has a very important role in the development of societies.

Since the emergence of cities and the beginning of urban planning and urbanization is closely related to the need for interaction and the sociality of human beings, undoubtedly, these relationships need their own spaces. Cities are known as places of the emergence of human social relations throughout history, and even the type and quality of urban spaces have been quite effective in the manifestation of these relations. Therefore, one of the most important elements of the urban context is the city structure formed and evolved based on human lifestyle in different periods [15].

The changes experienced in modern cities are reflected in the urban space, and this leads to the gradual extinction of public spaces in the urban structure. Increased urbanization and migration are leading to a loss of integration of public open space in city centers.

4. Urban open spaces in iranian city structure

The physical morphology of the traditional city of Iran is to a large extent a cultural-historical response to the natural environment, especially, the climatic conditions of the Iranian plateau. Its extreme climatic conditions are characterized by a shortage of water, high evaporation than precipitation, intense solar radiation, high seasonal temperature ranges, and damaging dust and sand storms [2].

The structure of traditional Iranian cities has a special physical-spatial cohesion and order that is guaranteed by their richness and physical quality. One of the most important features is the continuity of the city and neighborhoods through the centers, main passages, and the bazaar, which has led to the formation of a clear and legible structure in the city and the continuity of the components and elements of the city. The composition and construction of the city in the past of Iran have been such that the main passages and the bazaar have been responsible for the connection between the important elements of the city [16].

One of the important features of the old context of Iranian cities is its division into several neighborhoods because the historical city as a whole is composed of components in the form of a neighborhood [17]. In general, in Iran, the city was complex. Consisting of homogeneous and homogeneous neighborhoods that are integrated into a specific place based on relations, forms, and affiliations of ethnic, religious, professional, or territorial, and have kept their identity and originality in this way for years and until the new development. The city was considered as the main constituent units or as the cells of the city, the residence of a particular ethnicity, religion or group, and more than any other urban unit, within itself solidarity, unity, ethnic, family, and sometimes administrative, professional and class [18].

What has always been prominent in the construction and establishment of neighborhoods are the aspects of social, cultural, religious, or economic commonalities [17] and in the meantime, the separation of neighborhoods on the basis for differences in religious or ethnic beliefs and characteristics is more visible among large cities with larger and more diverse populations and in nomadic cities. For the emergence of each neighborhood, a limited and coherent geographical area, social interdependence between a specific group, and a specific city design were required for the spaces and houses of the neighborhood, the existence and permanence of the neighborhood depend on their existence [18].

The structure of ancient cities is known as the most obvious and complex part of the physical system that shows the social structures of the city along with its internal contradictions. Dynamics in the design of this structure causes logical relationships between urban components and systems and their function and process together.

One of the ways to organize the space in the historical cities of Iran was to connect the building mass continuously. This method can be seen at the micro level, such as neighborhoods, and at the macro level, as the whole city. For example, the bazaar, as the main and central street of the country, has been an important tool for the continuous growth of the city [19]. Next to, or along, some of the major bazaars in major cities were an urban or regional square. The bazaar was the most important road in the city and in most cases, it was connected to an urban square.

The main bazaar of cities are often linear and formed along the most important urban road. For this reason, in many historical cities of Iran, the most important part and the main element of the context is the main direction of its bazaar. A bazaar order was formed in its simplest form with shops located on either side of it. Many bazaars were gradually built and developed, and for this reason, the extension of the direction of these bazaars, following the natural shape of the passages, has been indirect and organic. Various guilds were stationed along the main bazaar line, thus placing various activity groups in different parts of the mainline. In some large cities, two or more main directions appeared in parallel or intersecting.

One of the main features of past spaces is their centrality and confinement. Each spatial area is central to its surroundings. Gradually, the construction method of the central building replaced the central space. The part of the building that could not be designed due to the connection with the adjacent building was exposed from all sides by being located in the middle of the space, and the necessity of designing all aspects of the building was raised. Each building peaked independently of adjacent buildings in height so that the horizontal connection gave way to the vertical connection [20].

One of the historical cities of Iran is Isfahan, located in the hot and arid area close to the desert while a river is passing through the city. Isfahan has a very special city structure based on various environmental issues. However, urban open spaces play an essential role in city structure.

5. Spatial structure of Isfahan based on urban open spaces

Isfahan is located in 32°38′30″ N latitude and 51°38′40″ E longitude, about 340 km south of Tehran and the capital of Isfahan Province (Figure 1) [22]. The main factors of the prosperity of Isfahan during the time have been the Zayandehrud River and the location of the city in the center of the Iranian plateau. So, throughout its history, it has been either the capital or one of the most important parts of Iran [23].

Figure 1.

Location of Isfahan in Iran [21].

The spatial-physical structure of each city is closely related to its history. Therefore, a review of historical periods can enlighten how the city is organized during the time. Most of the old cities of Iran had a specific structure of the main urban elements and functions such as palaces, bazaars, squares, mosques (After Islam), schools, etc. The physical characteristics of the evolution and development of the main structure of Iranian cities up to the contemporary era were mainly in harmony with the growth of the city [24].

The city of Isfahan has been continuously evolving for more than 2000 years. Until the early Islamic centuries (750–1258), Isfahan consisted of two districts, Jay and Judea (Figure 2). During the Sassanid Empire, Jay was the administrative and governmental center and included urban elements, such as squares and bazaars. In contrast, Judea and the rural agricultural areas in the north and south of the Zayandehrud River were inhabited [26].

Figure 2.

Isfahan in the late Sasanian and early Islamic periods (Abbasid era) [25].

After the Arab invasion of Isfahan, in the Abbasid era, Jay gradually became a ruin, while Judea survived. The physical form of the city in the pre-Islamic era included three distinct parts: the governmental area, the central city, and the outer city, but in the Islamic time, the past structures underwent changes, the most important of which was the Grand Mosque (Jame Mosque), as a characteristic of the urban element [27]. Rural groups connected with lines of communication and formed an urban body (Figure 2) [28]. The structure of Isfahan in the Seljuk era (1037–1194) was a combination of linear and centralized patterns. Due to the comprehensive development of the city, the central position of the structure was located around the Old Square as the main center of access. The linear part of the city structure has continued in the form of a bazaar to the gates, which has provided the possibility of development in the future [29]. Therefore, the most important urban spaces in this period have been squares, bazaars, and transportation routes which are created the structure of the city (Figure 3) [31].

Figure 3.

Structure of Seljuqid Isfahan. Modified by authors [30].

After the selection of Isfahan as the capital of Iran in the Safavid Empire (1501–1722), the main structure of the city was formed. During this period, Chaharbagh Street, Naghsh-e Jahan Square, and its connection to the Old Square by the bazaar was one of the most important measures in urban spaces. Naghsh-e Jahan Government-Ceremonial Square caused the future development of the city to be drawn to this direction and then to Hezarjarib gardens on the other side of the river (Figure 4) [33].

Figure 4.

Structure of Isfahan in Safavi era [32].

During the Qajar period (1789–1925), the empty space of the Old Square began to fill and lost its importance as a reference point in the structure of the city [34].

Over the Pahlavi period, modernism and its developments by ignoring the context, history, and structure of the city, introduced a kind of intervention in historical areas that led to spatial isolation and destruction of traditional structures in the city. During this time, the structure of the city was physically changed from a linear-nuclei model to a network structure, so that the old structure gradually faded in the minds of the people and lost its physical-structural value and reputation (Figure 5) [25].

Figure 5.

Structure of Isfahan in Pahlavi period [25].

The first planning measures in this period were street plans in the old contexts and their continuation to the outside based on the grid-system pattern and separation of urban functions, which led to the fragmentation of the old context of Isfahan [35]. This kind of intervention has led to the apparent separation of the main old parts of the city and the destruction of its traditional structure, which led to the complete decline of historical centers in the 20th century. Therefore, it was necessary to prepare master plans. Modern major urban planning began in Iran in the 1950s and 1960s when the first master plans were prepared for some important cities like Isfahan [36]. Isfahan has three main master plans in 1960, 1971, and 1988 (Figures 6–8). Then, detailed plans were prepared based on the regions of the city, but with the non-implementation of more than 70% of the comprehensive plans, the strategic development plans were replaced. City Development Strategy (CDS) is a comprehensive flexible planning framework designed to empower urban communities to control and manage the consequences of rapid economic change and increase the growth of economic and social inequalities [37].

Figure 6.

First master plan of Isfahan [35].

Figure 7.

Second master plan of Isfahan [35].

Figure 8.

Third master plan of Isfahan [35].

6. How urban spaces of Isfahan impact city structure?

The first question that should be answered is: what is the city structure? The structure of the city is a set consisting of the main axis and an interconnected network of land uses and urban elements that integrates the whole city and extends hierarchically in all parts of the city on a proportionate scale (Figure 9). This complex is the foundation of the spatial-physical organization of the city and indicates the general and common characteristics of the city [25].

Figure 9.

City structure: Main axis and an interconnected network of land uses and urban elements [25].

In other words, this complex as a linking structure includes parts of the city that are in public use, including movement structure (main roads, public transport cores, and main walking routes), interaction places, gathering places, and public buildings. City context with its specific physical and social characteristics is formed and organized by the city structure. This structure breaks the experience of the city into pieces with spatial locations and at different scales that make the city legible and conceivable. It changes over time and the elements that remain unchanged create the cultural landscape of the city. This structure can also be linked to the natural landscape (Figures 10 and 11) [38].

Figure 10.

City structure elements (authors).

Figure 11.

City structure: Movement structure, interaction and gathering places, and public buildings [25].

The second question is what is the urban open space? Urban space is the scene where the story of social life begins. It is a space that allows all people to access and work in it. Based on researches, there are different points of view about urban open space typologies (refer to [39]) but the focus of this study is based on five main categories: entrances urban nodes especially squares, paths, water edges, and urban stairs. The entrance is a joint for connecting two places. The entrances of the cities and the neighborhoods entrances are public spaces that play the role of urban space. Squares are the most influential urban spaces in the mental image of citizens. They can be on an urban, local scale, or play as a ceremonial place. In people’s minds, paths are not only the lines that enable the connection of different parts of the city, but also the spaces that accommodate the most social life. They have the largest share of other urban spaces and are manifested in the form of urban streets, passing streets, local streets, boulevards, alleys, dead ends, and pedestrian ways. Water in the city can play a key role. The water’s edges can be the basis of different social happenings. The last one is urban stairs which can be a place of social events in addition to the physical role of access (Figure 12) [40].

Figure 12.

Urban space typology.

According to the above issues, the last question is what is the role of urban open spaces on the structure of Isfahan? The following diagrams show the evolution of changes in the city structure over time and the interaction of these two main factors.

As mentioned, Isfahan initially consisted of two main cores and the dominant activity model of the people of the city was gardening. These gardens were mainly located on the banks of the Zayanderud River, and people had learned to use the River to irrigate their gardens, thus “Madi’s were formed. This pattern of residential activity may be the answer to the question of why the early settlements of Isfahan were formed at a distance from the Zayanderud River. Supplying water through wells was much easier than supplying water to gardens, in addition to the fact that the river was not permanent. People created branches (Madi) from the Zayanderud to deliver water to the gardens in a controlled manner [41].

In the Sassanid period, Zayanderud, Madies, two main cores (Jay and Yahudiyyah), and scattered points of residences created the basis of Isfahan’s structure in the multiple nuclei model. The river and Madies, as the first urban open spaces, played a significant role in locating the centers. In addition, the settlements around Yahudiyyah were organized by the Madies in a linear-nuclei connection (Figure 13).

Figure 13.

Isfahan structure in late Sassanid. The structure is linear-nuclei. Edited by authors [42].

In early Islam, the Isfahan spatial organization remained in linear-nuclei type, but the residential areas around Yahudiyyah joined together and organically formed in central organizing. This area is the foundation of the development of settlement as a city in the next years. The oldest neighborhood of Isfahan is in this part of the city and at the same time, functions such as bazaar and mosque were formed next to the palace. Zayanderud and Madies played their role as previous years in the structure of the city (Figure 14).

Figure 14.

Isfahan’s structure in early Islam. The structure is linear-nuclei. Edited by authors [26].

During the Seljuk period, the foundations of the Iranian-Islamic city emerged and the first square of the city was formed at the linkage of Joybareh, Dardasht, and Karan neighborhoods and next to the bazaar. The square and the bazaar, as the main urban spaces, formed the core structure of the Seljuk city along with the paths leading to the city gates. The city gates, as key points of crossing the city wall, strengthen the structure. In this period, the structure of the city core is central-radial with a predominant orientation northeast-southwest and on a larger scale with the Madies and the river is as a linear-nuclei (Figure 15).

Figure 15.

Isfahan structure in Seljuk era. The structure is central-radial in central of city and linear-nuclei on a larger scale. Modified by authors [26].

During the Safavid period, with a rapid increase in population, four gardens in the middle of the city became residential areas, and the government decided to create new gardens instead of ones that had changed their use, and so the gardens appeared around Chaharbagh Street [41]. Thus, the structure of the city was drawn to the south under the influence of the street route. New Square (Naghsh-e Jahan) was built in linkage to the bazaar between Faden and FarshadiMadies, and following the connection of Khajoo Bridge to Naghsh-e Jahan Square, another part of the city structure was directed to the southeast (Figure 16). The crossing of Chaharbagh over the river towards HezarJerib gardens and the axis of Khajoo towards the Takht-e-Foolad Cemetery brought the river to the heart of the city structure. These intersections designed the structure of the city as an interconnected network (Figure 17).

Figure 16.

Naghsh-e Jahan Square [43].

Figure 17.

Unban open space along the Zayandehrudriver [44].

It is worth noting that before the Safavid era the growth of the city was organically based on Madies and the river but at this time, the city was developed according to the designed plan (Figure 18).

Figure 18.

Isfahan’s structure in Safavid era. The structure is an integrated network. Modified by authors [26].

During the Pahlavi era with the aim of renovating the worn-out contexts left from the Qajar period, street construction continued based on the previous structure (Figure 19).

Figure 19.

Isfahan’s structure in Pahlavi era (1956) [45]. The structure is networked.

During this time, the new structure expanded its network by passing through the old texture, regardless of the size and orientation of the context pattern. From this period onwards, the streets are the main public open spaces that shape the structure of the city (Figure 20).

Figure 20.

Isfahan structure in 1970’s and 1986 [46]. The structure is networked.

With the regeneration of the Old Square in the contemporary era, it returned to the structure of Isfahan and along with the bazaar and Naghsh-e Jahan Square, physically organized the historical core of Isfahan (Figure 21).

Figure 21.

Old Square [47].

So as a result, the evolution of the structure of Isfahan over time is as follows (Table 1):

Time	Structure type	Open spaces affecting the structure
Late Sassanid	Linear-nuclei	Nodes (Residential areas)
		Water edges (Zayanderud and Madies)
Early Islam	Linear-nuclei	Nodes
		Water edges (Zayanderud and Madies)
Seljuk Era	Central-radial in central of city linear-nuclei in larger scale	Entrances (Gates)
		Paths
		Nodes (Old Square)
		Water Edges (Zayanderud and Madies)
Safavid	Integrated network	Entrances (Gates)
		Paths (Chaharbagh/Bridges)
		Nodes (Old Square and Naghsh-e Jahan square/HejarJerib Garden/Takht-e-Foolad)
		Water edges (Zayanderud and Madies)
Pahlavi	Network	Paths (Chaharbagh/Bridges)
		Nodes (Naghsh-e Jahan Sauer/JolfaSquare/Takht-e-Foolad)
		Water edges (Zayanderud and Madies)
NOW	Network	Paths (Chaharbagh/Bridges/Main streets)
		Nodes (Naghsh-e Jahan square/Sofe Mountain/Takht-e-Foolad)
		Water edges (Zayanderud and Madies)

Table 1.

Development of Isfahan structure and the main urban spaces affected over time.

7. Conclusion

Today, the viewpoint of natural and indigenous conservation refers to the fact that by maintaining and strengthening the indigenous structure, the social capacities of the place can be formed [48]. Urban open spaces are the main components and the most basic elements in the physical structure of a city. By identifying them, as well as determining their role in space and connecting their functions, we can take action to revitalize the ossification of traditional cities. This strategy is reinforced by defining a multifaceted role for them and a new skeleton is expected to be formed in the city. With such an approach to changing the structure of the city and strengthening the urban joints that connect the past and history to the present and the future and diverse activities to each other and citizens to civic life, the quality of urban places and spaces is improved and sense of richness and belonging strengthen.

Urban open spaces as vital factors play an important role in connecting the constituent elements of the city. The old context of cities, due to the preservation of their original structure, has appropriate models for recognizing and analyzing life-giving open spaces. These open spaces generate hierarchical space organization; breathing spaces among solid parts and city livability. Regarding the modernization process of cities, these valuable spaces were faded while mass spaces are mostly considered. It has resulted in very massive urban contexts affecting social interaction, legibility, city image, etc. Isfahan as one of the historical cities of Iran is well-known because of its urban open spaces which create specific city structure.

As mentioned, entrances, key points (nodes), roads, and water edges are the main urban spaces that in each period in the form of city gates, squares, and Madies routes and the river have strengthened the structure of the city. During the Safavid period, these elements in an integrated connection cause the expansion of the city to the south. With the passage of Chaharbagh through the Zayanderud River, the river finds a central role in the structure of the city, and these two artificial and natural axes form the foundation of the city’s later expansions. During the Qajar period and after that, the Old Square and the Madies lost their role in the structure of the city. With the construction of several streets during the Qajar, Pahlavi, and contemporary eras, the structure of the city expands in the form of a network and the roads are the main elements of the city.

Today, with the revitalization of the valuable historical structure of the city, such as regeneration of the Old Square and also rehabilitation of Madies green network, their role in the structure of the city has regained its importance.