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Volume 37, Issue 4 (2022)
GeoRes 2022, 37(4): 497-508 |
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Received: 2022/08/1 | Accepted: 2022/10/24 | Published: 2022/11/1
Received: 2022/08/1 | Accepted: 2022/10/24 | Published: 2022/11/1
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Hosseini Nejad J, Shahzeidi S, Shokrgozar A. Urban Spatial Syntax Logic in the Coastal Plain Northern Coast of Iran. GeoRes 2022; 37 (4) :497-508
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1- Department of Geography and Urban Planning, Faculty of Literature and Humanities, University of Guilan, Rasht, Iran
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Introduction
Human perception of the environment is shaped by a reciprocal relationship with it. In other words, environmental perception is both a subjective and objective process that emerges through interactive engagement with the surroundings. Geographic characteristics of a region can also influence the way humans perceive and understand their environment. Coastal areas, as the interface between land and water, have historically held significant value and have been sites for the emergence and growth of civilizations and population centers. Cohen et al. (1997) note that approximately 40% of the global population in 1995 lived within 60 kilometers of the coast, highlighting the importance of coastal areas as major population hubs. In a subsequent study, Cohen and Small (1998) found that about one-fourth of the world’s population, along with many major cities, are located within 100 kilometers of the coast and less than 100 meters above sea level. According to projections by Phillips and Jones (2006), 75% of the global population will reside within 60 kilometers of the coast by 2020. The sea and coastline form the foundational identity of coastal cities, and any spatial analysis that ignores this identity axis remains incomplete.
Heidegger, in his essay “Building, Dwelling, Thinking,” explored the relationship between dwelling, building, and thinking through a phenomenological approach, analyzing the connection between humans and place (Heidegger, 1971). Identity manifests culture in place and derives meaning from elements such as time, space, and culture, with its prominence varying over historical periods. Therefore, this concept plays an undeniable role in shaping the identity of Iranian habitats (Babajamali, 2014). Place identity refers to the unique characteristics of a location that reflect its historical memory, forming a sense of belonging for its inhabitants (Ahmadipour & Mirzaei Tabar, 2011).
In the context of spatial arrangement as a method for studying urban form, Hillier and Hanson developed space syntax theory, providing rules for spatial configuration. Space syntax is not merely a modeling tool but a method to understand the complexities of urban centers, their morphological logic, development patterns, and behavioral patterns within them (Hillier & Hanson, 1984; Hillier, 1996, 2007). It serves as a foundation for analyzing spatial structures using concepts such as land context, land text, and configuration, which are essential for studying settlements and environmental interactions (Nematollahi, 2014).
Phenomenology, as an epistemological approach, is also utilized in this study. It seeks to understand phenomena beyond tangible objects, considering human experience beyond purely objective data. Developed by Husserl and Heidegger, phenomenology provides a framework for exploring the essence of place and spatial experience (Partovi, 2013).
Geomorphic and historical evidence suggests that the physical environment, such as Quaternary lakes, influenced the formation and growth of population centers in Iran. Ramesht (2001) classifies Iranian regions based on natural factors that contributed to the development of civil centers. Nematollahi et al. (2018) examined coastal formations and geomorphic rules of settlement in southern Iran, revealing distinct settlement patterns influenced by natural features, particularly in Khuzestan compared to other Persian Gulf coastal areas.
Sarkar (2010), using RS and GIS to analyze settlement patterns in the western Bengal plains, have demonstrated that spatial arrangements of settlements provide insights into both contemporary socio-economic conditions and historical settlement processes. Ramesht et al. (2019) have compared place memory and identity between Germany and Iran from a phenomenological perspective, showing that German urban settlement identity follows geomorphic and hydrological rules, while rural settlement evolved from forest-based social structures. Mohammadian et al. (2019) have analyzed village and city layouts in the Khuzestan plain, demonstrating how river behaviors of bifurcation and meandering shaped settlement attractiveness and collective urban identity. Amirahmadi et al. (2011) highlight that glacial movements during the ice age influenced village distribution and limited urban development in certain plains.
This study aims to understand the perception of settlement spatial arrangement in relation to natural elements. The central research question is whether coastal settlements in the Caspian Plain follow specific spatial rules and what logic governs their configuration
Methodology
This research is a phenomenological study, primarily focused on the theoretical perspectives of space syntax and place identity. According to these perspectives, questions often arise regarding the logic governing the spatial arrangement of settlements, the role of place identity in their formation, and the contextual frameworks in which social structures manifest. The study aims to identify natural transformations that have contributed to the creation of geomorphic heritage in the region, classify these heritage phenomena, and examine their influence on place identity. It further explores how place identity affects the fundamental social units and settlements, ultimately uncovering the principles guiding their spatial configuration.
Emphasizing recent concepts in geomorphology, the study employs spatial analysis and interpretive strategies to analyze patterns and extract the logic underlying settlement arrangements within the study area. To achieve the research objectives and answer the research questions, the following procedure was designed:
Step 1: Understanding the study area and the subject matter
Given the significant role of coastal spaces in regional development and sustainability, this step involved comprehending the subject and understanding the study area, highlighting the impact of natural heritage on regional planning.
Step 2: Preliminary studies
Initial studies were conducted through thematic literature reviews, examination of books, academic articles, theses, and dissertations, as well as online resources.
Step 3: Data preparation
Data were collected within the framework of the research design from various sources, including digital elevation models (DEM), satellite imagery, topographic and geological maps, demographic data, and field visits. DEMs are essential for many spatially oriented studies. In this research, DEMs with resolutions of 30 and 90 meters were used to extract watershed networks, define contour lines, water-land balance lines, and ice-water balance lines as geomorphic components.
Additionally, a 30-meter resolution digital surface model (DSM) provided by the Japan Aerospace Exploration Agency (JAXA) through the Advanced Land Observing Satellite (ALOS) and the Earth Observation Research Center (EORC) was utilized [EORC, 2018]. Satellite images from SID and Google Earth were used to identify specific geomorphic features when higher precision was required. Topographic maps at a 1:50,000 scale, provided by the Geographic Organization of the Iranian Ministry of Defense and Armed Forces Logistics, were also employed. Point data of urban and rural settlements and population statistics from the Statistical Center of Iran (2016) [Statistical Center of Iran, 2016] were used to define the demographic components, location, and population of settlements in the study area.
Step 4: Defining the study area boundaries
The spatial extent of the study was delineated using thematic maps and satellite imagery, based on precise geographic coordinates.
Step 5: Identifying geomorphic transformations and components
Natural transformations responsible for the creation of geomorphic heritage were identified, and the most influential natural historical factors affecting settlement arrangements were determined.
Step 6: Delineating and analyzing land units in the Caspian coastal region
Using the concept of land context, the northern Iranian coastal region was divided into three units based on topographic variations, topographic maps at 1:50,000 scale, satellite imagery, and DEMs. After defining these land units, the area of each unit, as well as the number and population of settlements within them, were calculated and analyzed.
Step 7: Extracting spatial configuration rules
The logic governing settlement arrangement was analyzed, and the underlying spatial rules were identified.
Step 8: Data evaluation and analysis
Data were evaluated and analyzed to study spatial arrangements and urban settlement patterns. Visual representations and map production were conducted using software tools such as ArcGIS, Surfer, Global Mapper, and Excel.
Study Area
The study area encompasses the northern region of Iran, including Gilan and Mazandaran provinces, as well as part of Golestan province, covering an area of 39,371 km² along a 625-kilometer coastline. Geographically, the study area extends from 35°43′17.5891″ N to 38°28′19.9663″ N latitude and from 48°33′03.6995″ E to 54°29′32.3313″ E longitude.
Findings
Identification of Land Units and Geographical Contexts in the Northern Coastal Region of Iran
Using the concept of land units and based on land morphology and topographic features, the northern coastal region of Iran was delineated into three land units, relying on 1:50,000 topographic maps, satellite imagery, and digital elevation models. The first unit, the marine or coastal unit, includes the coastal plain with elevations ranging from -27 to 100 meters. The second unit, the piedmont or eroded hills unit, covers elevations from 100 to 800 meters and includes hilly terrains. The third unit, the mountainous or Alborz unit, encompasses elevations above 800 meters and includes coastal mountain ranges.
After delineating these land units, their areas were calculated. Using demographic data from the Statistical Center of Iran, the number, location, and population of settlements within each land unit were determined. The coastal unit has the highest number of cities and population, while the mountainous unit is the largest in terms of area.
To extract the logic of settlement patterns, two contexts and their associated geographical settings were identified. In the first context, the transformative role of rivers was analyzed using Hillier's method, revealing that rural settlements in riverine areas follow a convergence rule. Urban settlements in this context adhere to a size-distance rule. In the second context, settlement distribution was aligned with the ice-water equilibrium line (IWEL), showing that rural settlements near glacial areas follow this equilibrium line.
Analysis of the Coastal (Marine) Unit and Settlement Identity
Lake systems in Iran during cold periods were among the largest and most influential land contexts, often surrounded by terraced landforms indicative of wetter periods. Coastal units, especially along the Caspian Sea, represent geomorphological heritage shaped by changes in water level and have historically supported large human populations.
Riverine Influence on Urban Settlements
Rivers in the coastal unit play a transformative role in shaping settlements. Using digital elevation models and hydrological network analysis, the spatial configuration of rivers was mapped and compared with settlement locations. The analysis showed that convergence points of river networks strongly influence the establishment of urban centers, creating a spatial identity that attracts human communities and fosters urban development.
Coastal Terraces and Settlement Formation
The highest coastal terraces of the Caspian Sea historically reached elevations of up to 55 meters above current sea levels. The most populous coastal belt of Iran formed on these ancient lakebeds. The relationship between coastal terraces, water-level lines, and settlement patterns was analyzed using topographic maps, satellite imagery, and DEMs. Results show that settlements near the current shoreline are smaller and fewer in number, while population and settlement size increase progressively with elevation, following a size-distance principle relative to terrace height.
Analysis of the Mountainous Unit and Settlement Identity
In the mountainous unit, the spatial distribution of settlements is influenced by glacial features. Morphological analysis of glacial landforms, including cirques, using topographic maps and DEMs, identified significant concentrations of glacial features at specific elevations. In Gilan, approximately 347 cirques were identified between 2,000 and 2,700 meters, while in Mazandaran and parts of Golestan, around 1,874 cirques were distributed between 2,000 and 4,200 meters. The densest concentrations occur at 2,100–2,200 meters in Gilan and 2,900–3,000 meters in Mazandaran, accounting for over 50% of cirques.
Using these features, permanent snow lines were estimated with the Wright method, and the ice-water equilibrium line was determined. In Gilan, this line was approximately 1,780 meters, and in Mazandaran, around 2,380 meters, corresponding to past average temperatures near 5°C. These lines were then used to analyze settlement patterns, showing that rural settlements in mountainous regions are closely aligned with glacial and ice-melt processes.
Mountainous Unit and Rural Settlement Cores
Permanent snow lines and glacial tongues play a key role in defining the ice-water equilibrium and guiding the formation of settlements. Rural settlements in mountainous areas follow the movement and shaping of glacial features. The first settlement cores often emerge near these equilibrium lines, establishing the spatial logic of rural settlement patterns. These areas provide environmental attraction and a sense of place identity, forming the foundation of rural social structures. The settlement logic can thus be interpreted as the intersection of glacial influence and thermal conditions.
Discussion
If geographical landscapes are considered as a text, spatial arrangement is an effort to express the understanding of the configuration or structure that links the elements of a landscape and manifests social or cultural meaning. Geographical and geomorphological texts or landscapes represent objectified meanings, whose perception, discovery, and understanding by humans have led to the formation of settlement patterns. The spatial arrangement of settlements follows a particular logic and adheres to specific rules. It is noteworthy that the sustainability of settlements depends on various factors, including place identity. Therefore, uncovering the logic of spatial arrangement, as one of the main pillars of epistemology and a key method in spatial morphology, is of great importance.
Settlement patterns and social structures have been strongly influenced by the contexts of the land and Quaternary climatic conditions. Hence, paleoclimate information and tracing geomorphic evidence of climatic changes help elucidate many issues related to human life. What is emphasized in this research is the understanding of geomorphological analyses regarding the rules of settlement patterns, especially within the study area. Information on the habitats of civilizations and population centers, as well as the effects of natural and climatic changes on human livelihoods, explains many environmental realities and highlights that the emergence of civilizations has not been uniform worldwide; rather, the formation of population centers follows specific natural logics depending on environmental conditions.
In the spatial arrangement method, which forms the foundation for understanding the organization of space and the relational arrangement of all spaces, the researcher focuses on the positioning of phenomena and the geometric and mathematical rules governing this arrangement. Therefore, spatial relationships can be represented through conceptual, mathematical, or graphical models (Chang, 2018). In other words, the positioning and spatial configuration of phenomena within geographic areas determine the governing rules of the environment. For instance, the logic of settlement arrangement along the Persian Gulf coast can be defined in terms of the number and size of population centers. In this context, population centers change in number and size with increasing distance from the coast; coastal settlements are few but densely populated, while settlements farther inland increase in number but decrease in population size (Nematollahi et al., 2018). In other words, the spatial arrangement logic follows an inverse Newtonian gravity law.
Regarding the Caspian Sea coast, the spatial logic differs from that of the Persian Gulf. Moving from the Caspian coast toward the mountains, the size-distance law governs the settlement pattern: as distance from the coast increases, population centers decrease in number but increase in size and extent.
Another significant factor is the role of rivers and their relationship with settlements. For example, the behavior of the Karun and Karkheh rivers in the Khuzestan plain determines the arrangement of rural and urban settlements (Mohamadiyan, 2017). The arrangement of villages and towns in the Khuzestan plain follows the identity-creating function of the Karkheh and Karun rivers, with the derived formula expressed as a rule for identity-based settlement patterns. Two river behaviors within a marine context create two types of identity-attractive settlement patterns: bifurcation behavior produces urban settlement patterns, and meandering behavior shapes rural settlement patterns.
In the Caspian study area, analysis of river behavior in relation to rural settlements shows that urban centers are located only where rivers exhibit convergence. Another factor is the advance of glaciers and its relation to settlement establishment. During cold periods, mountainous regions accumulated more solid precipitation, which formed glacial rivers flowing toward lower plains. These glacial advances did not reach the center of the plains but melted midway due to environmental warming, joining downstream lakes as runoff. Villages emerged at the point where glaciers had to melt (Ice-Water Equilibrium Line: IWEL), coinciding with a thermal surface based on prior calculations suggesting an average annual temperature of approximately 5–6 °C (Ramesht, 2004).
All these observations emphasize the significance of the land and the influence of place identity on human perception and experience of coastal and mountainous contexts, which broadly contribute to the formation of spatial-biological patterns.
Conclusion
Spatial arrangement encompasses theories and methods that focus on the mutual effects of forms and processes, increasingly emphasized in regional planning. Based on this idea, various spatial analysis methods, such as spatial configuration analysis, have been developed, enabling the decomposition of space into its constituent elements and the analysis of these elements within a network of geographical contexts. One of the foundational principles of the spatial arrangement method is the existence of a reciprocal relationship between space and socio-biological patterns, implying that the configuration of settlements can be regarded as the tangible manifestation of natural-historical contexts, i.e., their place identity.
The Caspian Sea coasts have undergone specific natural-historical transformations, which, although no longer active, have left legacies that define the current place identity. This identity has played, and continues to play, a major role in the rules governing the arrangement of current habitats and the spatial planning of these areas. The region, influenced by these geomorphic events, exhibits particular histories and behaviors, through which we today experience fundamental geomorphological concepts such as river expansion and the formation of terrace levels as natural-historical heritage.
The core focus of this study has been the examination and understanding of the impact of these legacies on regional planning. In other words, understanding and classifying these natural-historical legacies—each originating from a specific period—can guide us in comprehending the principles and rules governing land use planning. Geographical landscapes, or geographical texts, are interpretable like literary texts; thus, for any phenomenon within space, the configuration patterns and their governing rules can be extracted and even modeled
Acknowledgments: None reported by the authors.
Ethical Permission: None reported by the authors.
Conflict of Interest: No conflicts of interest exist.
Author Contributions: Hosseini Nejad J (First Author), Introduction Writer/Discussion Writer (33%); Shahzeidi SS (Second Author), Main Researcher (34%); Shokrgozar A (Third Author): Statistical Analyst (33%)
Funding: This article is based on the Master’s thesis of the first author, supervised by the second and third authors. All expenses were personally funded.
Human perception of the environment is shaped by a reciprocal relationship with it. In other words, environmental perception is both a subjective and objective process that emerges through interactive engagement with the surroundings. Geographic characteristics of a region can also influence the way humans perceive and understand their environment. Coastal areas, as the interface between land and water, have historically held significant value and have been sites for the emergence and growth of civilizations and population centers. Cohen et al. (1997) note that approximately 40% of the global population in 1995 lived within 60 kilometers of the coast, highlighting the importance of coastal areas as major population hubs. In a subsequent study, Cohen and Small (1998) found that about one-fourth of the world’s population, along with many major cities, are located within 100 kilometers of the coast and less than 100 meters above sea level. According to projections by Phillips and Jones (2006), 75% of the global population will reside within 60 kilometers of the coast by 2020. The sea and coastline form the foundational identity of coastal cities, and any spatial analysis that ignores this identity axis remains incomplete.
Heidegger, in his essay “Building, Dwelling, Thinking,” explored the relationship between dwelling, building, and thinking through a phenomenological approach, analyzing the connection between humans and place (Heidegger, 1971). Identity manifests culture in place and derives meaning from elements such as time, space, and culture, with its prominence varying over historical periods. Therefore, this concept plays an undeniable role in shaping the identity of Iranian habitats (Babajamali, 2014). Place identity refers to the unique characteristics of a location that reflect its historical memory, forming a sense of belonging for its inhabitants (Ahmadipour & Mirzaei Tabar, 2011).
In the context of spatial arrangement as a method for studying urban form, Hillier and Hanson developed space syntax theory, providing rules for spatial configuration. Space syntax is not merely a modeling tool but a method to understand the complexities of urban centers, their morphological logic, development patterns, and behavioral patterns within them (Hillier & Hanson, 1984; Hillier, 1996, 2007). It serves as a foundation for analyzing spatial structures using concepts such as land context, land text, and configuration, which are essential for studying settlements and environmental interactions (Nematollahi, 2014).
Phenomenology, as an epistemological approach, is also utilized in this study. It seeks to understand phenomena beyond tangible objects, considering human experience beyond purely objective data. Developed by Husserl and Heidegger, phenomenology provides a framework for exploring the essence of place and spatial experience (Partovi, 2013).
Geomorphic and historical evidence suggests that the physical environment, such as Quaternary lakes, influenced the formation and growth of population centers in Iran. Ramesht (2001) classifies Iranian regions based on natural factors that contributed to the development of civil centers. Nematollahi et al. (2018) examined coastal formations and geomorphic rules of settlement in southern Iran, revealing distinct settlement patterns influenced by natural features, particularly in Khuzestan compared to other Persian Gulf coastal areas.
Sarkar (2010), using RS and GIS to analyze settlement patterns in the western Bengal plains, have demonstrated that spatial arrangements of settlements provide insights into both contemporary socio-economic conditions and historical settlement processes. Ramesht et al. (2019) have compared place memory and identity between Germany and Iran from a phenomenological perspective, showing that German urban settlement identity follows geomorphic and hydrological rules, while rural settlement evolved from forest-based social structures. Mohammadian et al. (2019) have analyzed village and city layouts in the Khuzestan plain, demonstrating how river behaviors of bifurcation and meandering shaped settlement attractiveness and collective urban identity. Amirahmadi et al. (2011) highlight that glacial movements during the ice age influenced village distribution and limited urban development in certain plains.
This study aims to understand the perception of settlement spatial arrangement in relation to natural elements. The central research question is whether coastal settlements in the Caspian Plain follow specific spatial rules and what logic governs their configuration
Methodology
This research is a phenomenological study, primarily focused on the theoretical perspectives of space syntax and place identity. According to these perspectives, questions often arise regarding the logic governing the spatial arrangement of settlements, the role of place identity in their formation, and the contextual frameworks in which social structures manifest. The study aims to identify natural transformations that have contributed to the creation of geomorphic heritage in the region, classify these heritage phenomena, and examine their influence on place identity. It further explores how place identity affects the fundamental social units and settlements, ultimately uncovering the principles guiding their spatial configuration.
Emphasizing recent concepts in geomorphology, the study employs spatial analysis and interpretive strategies to analyze patterns and extract the logic underlying settlement arrangements within the study area. To achieve the research objectives and answer the research questions, the following procedure was designed:
Step 1: Understanding the study area and the subject matter
Given the significant role of coastal spaces in regional development and sustainability, this step involved comprehending the subject and understanding the study area, highlighting the impact of natural heritage on regional planning.
Step 2: Preliminary studies
Initial studies were conducted through thematic literature reviews, examination of books, academic articles, theses, and dissertations, as well as online resources.
Step 3: Data preparation
Data were collected within the framework of the research design from various sources, including digital elevation models (DEM), satellite imagery, topographic and geological maps, demographic data, and field visits. DEMs are essential for many spatially oriented studies. In this research, DEMs with resolutions of 30 and 90 meters were used to extract watershed networks, define contour lines, water-land balance lines, and ice-water balance lines as geomorphic components.
Additionally, a 30-meter resolution digital surface model (DSM) provided by the Japan Aerospace Exploration Agency (JAXA) through the Advanced Land Observing Satellite (ALOS) and the Earth Observation Research Center (EORC) was utilized [EORC, 2018]. Satellite images from SID and Google Earth were used to identify specific geomorphic features when higher precision was required. Topographic maps at a 1:50,000 scale, provided by the Geographic Organization of the Iranian Ministry of Defense and Armed Forces Logistics, were also employed. Point data of urban and rural settlements and population statistics from the Statistical Center of Iran (2016) [Statistical Center of Iran, 2016] were used to define the demographic components, location, and population of settlements in the study area.
Step 4: Defining the study area boundaries
The spatial extent of the study was delineated using thematic maps and satellite imagery, based on precise geographic coordinates.
Step 5: Identifying geomorphic transformations and components
Natural transformations responsible for the creation of geomorphic heritage were identified, and the most influential natural historical factors affecting settlement arrangements were determined.
Step 6: Delineating and analyzing land units in the Caspian coastal region
Using the concept of land context, the northern Iranian coastal region was divided into three units based on topographic variations, topographic maps at 1:50,000 scale, satellite imagery, and DEMs. After defining these land units, the area of each unit, as well as the number and population of settlements within them, were calculated and analyzed.
Step 7: Extracting spatial configuration rules
The logic governing settlement arrangement was analyzed, and the underlying spatial rules were identified.
Step 8: Data evaluation and analysis
Data were evaluated and analyzed to study spatial arrangements and urban settlement patterns. Visual representations and map production were conducted using software tools such as ArcGIS, Surfer, Global Mapper, and Excel.
Study Area
The study area encompasses the northern region of Iran, including Gilan and Mazandaran provinces, as well as part of Golestan province, covering an area of 39,371 km² along a 625-kilometer coastline. Geographically, the study area extends from 35°43′17.5891″ N to 38°28′19.9663″ N latitude and from 48°33′03.6995″ E to 54°29′32.3313″ E longitude.
Findings
Identification of Land Units and Geographical Contexts in the Northern Coastal Region of Iran
Using the concept of land units and based on land morphology and topographic features, the northern coastal region of Iran was delineated into three land units, relying on 1:50,000 topographic maps, satellite imagery, and digital elevation models. The first unit, the marine or coastal unit, includes the coastal plain with elevations ranging from -27 to 100 meters. The second unit, the piedmont or eroded hills unit, covers elevations from 100 to 800 meters and includes hilly terrains. The third unit, the mountainous or Alborz unit, encompasses elevations above 800 meters and includes coastal mountain ranges.
After delineating these land units, their areas were calculated. Using demographic data from the Statistical Center of Iran, the number, location, and population of settlements within each land unit were determined. The coastal unit has the highest number of cities and population, while the mountainous unit is the largest in terms of area.
To extract the logic of settlement patterns, two contexts and their associated geographical settings were identified. In the first context, the transformative role of rivers was analyzed using Hillier's method, revealing that rural settlements in riverine areas follow a convergence rule. Urban settlements in this context adhere to a size-distance rule. In the second context, settlement distribution was aligned with the ice-water equilibrium line (IWEL), showing that rural settlements near glacial areas follow this equilibrium line.
Analysis of the Coastal (Marine) Unit and Settlement Identity
Lake systems in Iran during cold periods were among the largest and most influential land contexts, often surrounded by terraced landforms indicative of wetter periods. Coastal units, especially along the Caspian Sea, represent geomorphological heritage shaped by changes in water level and have historically supported large human populations.
Riverine Influence on Urban Settlements
Rivers in the coastal unit play a transformative role in shaping settlements. Using digital elevation models and hydrological network analysis, the spatial configuration of rivers was mapped and compared with settlement locations. The analysis showed that convergence points of river networks strongly influence the establishment of urban centers, creating a spatial identity that attracts human communities and fosters urban development.
Coastal Terraces and Settlement Formation
The highest coastal terraces of the Caspian Sea historically reached elevations of up to 55 meters above current sea levels. The most populous coastal belt of Iran formed on these ancient lakebeds. The relationship between coastal terraces, water-level lines, and settlement patterns was analyzed using topographic maps, satellite imagery, and DEMs. Results show that settlements near the current shoreline are smaller and fewer in number, while population and settlement size increase progressively with elevation, following a size-distance principle relative to terrace height.
Analysis of the Mountainous Unit and Settlement Identity
In the mountainous unit, the spatial distribution of settlements is influenced by glacial features. Morphological analysis of glacial landforms, including cirques, using topographic maps and DEMs, identified significant concentrations of glacial features at specific elevations. In Gilan, approximately 347 cirques were identified between 2,000 and 2,700 meters, while in Mazandaran and parts of Golestan, around 1,874 cirques were distributed between 2,000 and 4,200 meters. The densest concentrations occur at 2,100–2,200 meters in Gilan and 2,900–3,000 meters in Mazandaran, accounting for over 50% of cirques.
Using these features, permanent snow lines were estimated with the Wright method, and the ice-water equilibrium line was determined. In Gilan, this line was approximately 1,780 meters, and in Mazandaran, around 2,380 meters, corresponding to past average temperatures near 5°C. These lines were then used to analyze settlement patterns, showing that rural settlements in mountainous regions are closely aligned with glacial and ice-melt processes.
Mountainous Unit and Rural Settlement Cores
Permanent snow lines and glacial tongues play a key role in defining the ice-water equilibrium and guiding the formation of settlements. Rural settlements in mountainous areas follow the movement and shaping of glacial features. The first settlement cores often emerge near these equilibrium lines, establishing the spatial logic of rural settlement patterns. These areas provide environmental attraction and a sense of place identity, forming the foundation of rural social structures. The settlement logic can thus be interpreted as the intersection of glacial influence and thermal conditions.
Discussion
If geographical landscapes are considered as a text, spatial arrangement is an effort to express the understanding of the configuration or structure that links the elements of a landscape and manifests social or cultural meaning. Geographical and geomorphological texts or landscapes represent objectified meanings, whose perception, discovery, and understanding by humans have led to the formation of settlement patterns. The spatial arrangement of settlements follows a particular logic and adheres to specific rules. It is noteworthy that the sustainability of settlements depends on various factors, including place identity. Therefore, uncovering the logic of spatial arrangement, as one of the main pillars of epistemology and a key method in spatial morphology, is of great importance.
Settlement patterns and social structures have been strongly influenced by the contexts of the land and Quaternary climatic conditions. Hence, paleoclimate information and tracing geomorphic evidence of climatic changes help elucidate many issues related to human life. What is emphasized in this research is the understanding of geomorphological analyses regarding the rules of settlement patterns, especially within the study area. Information on the habitats of civilizations and population centers, as well as the effects of natural and climatic changes on human livelihoods, explains many environmental realities and highlights that the emergence of civilizations has not been uniform worldwide; rather, the formation of population centers follows specific natural logics depending on environmental conditions.
In the spatial arrangement method, which forms the foundation for understanding the organization of space and the relational arrangement of all spaces, the researcher focuses on the positioning of phenomena and the geometric and mathematical rules governing this arrangement. Therefore, spatial relationships can be represented through conceptual, mathematical, or graphical models (Chang, 2018). In other words, the positioning and spatial configuration of phenomena within geographic areas determine the governing rules of the environment. For instance, the logic of settlement arrangement along the Persian Gulf coast can be defined in terms of the number and size of population centers. In this context, population centers change in number and size with increasing distance from the coast; coastal settlements are few but densely populated, while settlements farther inland increase in number but decrease in population size (Nematollahi et al., 2018). In other words, the spatial arrangement logic follows an inverse Newtonian gravity law.
Regarding the Caspian Sea coast, the spatial logic differs from that of the Persian Gulf. Moving from the Caspian coast toward the mountains, the size-distance law governs the settlement pattern: as distance from the coast increases, population centers decrease in number but increase in size and extent.
Another significant factor is the role of rivers and their relationship with settlements. For example, the behavior of the Karun and Karkheh rivers in the Khuzestan plain determines the arrangement of rural and urban settlements (Mohamadiyan, 2017). The arrangement of villages and towns in the Khuzestan plain follows the identity-creating function of the Karkheh and Karun rivers, with the derived formula expressed as a rule for identity-based settlement patterns. Two river behaviors within a marine context create two types of identity-attractive settlement patterns: bifurcation behavior produces urban settlement patterns, and meandering behavior shapes rural settlement patterns.
In the Caspian study area, analysis of river behavior in relation to rural settlements shows that urban centers are located only where rivers exhibit convergence. Another factor is the advance of glaciers and its relation to settlement establishment. During cold periods, mountainous regions accumulated more solid precipitation, which formed glacial rivers flowing toward lower plains. These glacial advances did not reach the center of the plains but melted midway due to environmental warming, joining downstream lakes as runoff. Villages emerged at the point where glaciers had to melt (Ice-Water Equilibrium Line: IWEL), coinciding with a thermal surface based on prior calculations suggesting an average annual temperature of approximately 5–6 °C (Ramesht, 2004).
All these observations emphasize the significance of the land and the influence of place identity on human perception and experience of coastal and mountainous contexts, which broadly contribute to the formation of spatial-biological patterns.
Conclusion
Spatial arrangement encompasses theories and methods that focus on the mutual effects of forms and processes, increasingly emphasized in regional planning. Based on this idea, various spatial analysis methods, such as spatial configuration analysis, have been developed, enabling the decomposition of space into its constituent elements and the analysis of these elements within a network of geographical contexts. One of the foundational principles of the spatial arrangement method is the existence of a reciprocal relationship between space and socio-biological patterns, implying that the configuration of settlements can be regarded as the tangible manifestation of natural-historical contexts, i.e., their place identity.
The Caspian Sea coasts have undergone specific natural-historical transformations, which, although no longer active, have left legacies that define the current place identity. This identity has played, and continues to play, a major role in the rules governing the arrangement of current habitats and the spatial planning of these areas. The region, influenced by these geomorphic events, exhibits particular histories and behaviors, through which we today experience fundamental geomorphological concepts such as river expansion and the formation of terrace levels as natural-historical heritage.
The core focus of this study has been the examination and understanding of the impact of these legacies on regional planning. In other words, understanding and classifying these natural-historical legacies—each originating from a specific period—can guide us in comprehending the principles and rules governing land use planning. Geographical landscapes, or geographical texts, are interpretable like literary texts; thus, for any phenomenon within space, the configuration patterns and their governing rules can be extracted and even modeled
Acknowledgments: None reported by the authors.
Ethical Permission: None reported by the authors.
Conflict of Interest: No conflicts of interest exist.
Author Contributions: Hosseini Nejad J (First Author), Introduction Writer/Discussion Writer (33%); Shahzeidi SS (Second Author), Main Researcher (34%); Shokrgozar A (Third Author): Statistical Analyst (33%)
Funding: This article is based on the Master’s thesis of the first author, supervised by the second and third authors. All expenses were personally funded.
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