Military Strategies of Roman Cities Establishment Based on the Space Syntax Analysis Applied to the Vestiges of Timgad

Abstract

Roman cities represent the Empire’s broader approach to urban planning, characterized by geometric precision and a strategic layout. Their spatial organization reflects the underlying military and administrative objectives, which can be better understood through new analytical tools. This research investigates the Roman military strategy behind the establishment of Timgad, a Roman archeology in Algeria, using Space Syntax Analysis (SSA) to examine its spatial and urban structure. This study highpoints how its spatial configuration was intricately linked to military tactics aimed at asserting control and dominance by analyzing the city’s grid-like layout and applying SSA indicators, such as Connectivity, Integration, Entropy, Control, Controllability and Through Vision (via Axial Map and Visibility Graph Analysis). The results show high value in these indicators, especially in areas where military structures were strategically located along main roads and key urban nodes, demonstrating a careful exertion to maintain surveillance and authority over space. This spatial configuration reveals a deep synergy connecting military logic and urban design, sustaining the idea that Roman town planning supported both functional and symbolic roles in establishing imperial authority. This study concludes that Roman military strategy was not only central to their territorial expansion but also instrumental in shaping long-lasting urban models, influencing the structure of colonial cities far beyond their time. Timgad thus serves as an influential case of how military requirements shaped the built environment in the Roman Empire.

1. Introduction

During the Pax Romana, Rome extended its impact beyond conflict, establishing lasting peace within the Mediterranean [1]. Roman emperors recognized the strategic and economic potential of North Africa, especially Algeria (then part of Numidia and Mauretania Caesarean), valuing its fertile lands and agricultural bounty [2,3]. Roman control progressively expanded from coastal cities into the high plains, mountainous regions like the Aurès, and eventually to the southern desert zones, where military bases defended logistical routes and borders [3,4]. The inclusion of Numidia (in modern-day northeastern Algeria) in the Roman Empire exhibited a multifaceted imperial strategy that combined governance, agriculture, and military logistics [5,6]. The resulting network of more than 500 Roman cities, including Cirta, Hippo Regius, Cuicul, and Thamugadi, represents remains of urban planning, infrastructure, and trade networks that reinforced Rome’s domination in the region [7,8].

Roman military strategy, particularly in the establishment of cities, was based on the logic of territorial domination, logistical control, and the projection of imperial order through urban planning. As Goldsworthy [1] points out in Pax Romana, Roman peace was not simply the absence of war, but rather a spatial organization designed to prevent unrest through a strong military presence and a hierarchical urban infrastructure. The establishment of cities, often laid out in rigid orthogonal grids (as at Timgad), responded to military imperatives: enabling rapid troop movement, ensuring surveillance of local populations, and imposing a Roman model of civilization [4,9]. This rational grid, inherited from the military camp (castrum), reflected a desire for order and strategic efficiency, as confirmed by Jones [10], who sees provincial urban planning as a direct extension of the centralized imperial administration. Mattingly [3] reinforces this interpretation, showing that Roman urbanization in Britain responded not only to military needs but also to the symbolic goal of cultural annexation. However, this strategy was not without contradictions: Shaw [11] notes that the imposition of a standardized urban order did not guarantee homogeneity of occupation or control, particularly in North Africa, where local dynamics could redefine the actual use of urban structures. In short, Roman cities were not merely civil entities but tactical instruments of power, whose spatial form embodied the imperial logic of domination through order, visibility, and mobility.

The foundation of Timgad in 100 CE by Emperor Trajan must be understood within the broader political–military context of his imperial strategy in North Africa [12]. As a Roman colonia established for veterans of the Third Augustan Legion, Timgad was not merely a settlement, but a strategic outpost designed to secure the empire’s southern frontier. It served as a base for projecting Roman authority into surrounding Berber territories, facilitating both military oversight and cultural integration. Its rigid grid layout and monumental urban features reflected Rome’s intent to assert control, enforce order, and symbolize imperial presence deep within the African provinces [13]. In the tradition of Roman colonial planning, Thamugadi (called Timgad today) exemplifies the principles of Roman military urbanism. Timgad preserves a near-perfect orthogonal grid plan that exposed Roman principles of order, mobility, and visibility [14,15]. Its layout performed as a model for later Algerian urban forms, demonstrating the enduring influence of Roman spatial organization on urban design.

To better understand such spatial legacies and their influence on human movement and interaction, Space Syntax Analysis (SSA) has emerged as a key tool in the study of spatial configurations, offering insights into how the built environment both shapes and is shaped by human behavior across different cultural, historical, and urban contexts. Current research has prolonged its application to improving urban accessibility and pedestrian safety, as shown by Fan et al. [16] in the historical city of George Town, Penang, where spatial syntax permitted the identification of connectivity patterns critical for urban renewal and safety planning. Similarly, Sun et al. [17] applied SSA in rural and ethnically diverse settings, proving its value in supporting revitalization strategies through syntactic properties such as integration and depth. Jiang et al. [18] used the methodology to search the spatial morphology of innovation-driven industrial parks in Tianjin, underlining the importance of external configurational features in post-industrial urban heritage. These studies illustrate how SSA supports data-driven involvements across diverse scales and typologies, from dense urban cores to rural settlements, emphasizing its adaptability and effectiveness in contemporary spatial planning.

In historical and archaeological fields, SSA has developed progressively, being increasingly valued for understanding the spatial logic of past societies. Yin et al. [19] explored the comparative spatial characteristics of the Tang and Song dynasty capitals, revealing distinct urban ideologies embedded in their layouts, while Yang and Liu [20] developed a framework combining SSA with historical GIS to map urban spatial evolution in Xi’an. In archaeological contexts, researchers such as Ulrich Thaler [21] advocate for the integration of space syntax into broader spatial analytical toolkits, highlighting its potential for reconstructing human activities and movement patterns in ancient environments. Theoretical advancements by Hillier [22] and methodological critiques by Pafka et al. [23] have further refined the application of SSA, emphasizing its limitations as well as the importance of scale and representational accuracy. The expanding scope of SSA, from modern urban analysis to historical and archaeological research, not only confirms its interdisciplinary sturdiness but also calls for ongoing theoretical engagement [24,25].

SSA is an efficient method applied across various urban and architectural research domains, including social, cultural, environmental, and archaeological studies [21,26,27]. This approach investigates metrics such as integration, connectivity, and intelligibility, offering new insights into how cities were organized for strategic orientation, communication, and control [28,29,30,31]. These analytical tools enable archaeologists and anthropologists to reconstruct Roman approaches to urbanism and military efficiency, highlighting the interaction between architectural precision and socio-cultural demands in imperial planning [21,32,33].

This study addresses a theoretical gap by investigating how Roman military strategy influenced the spatial organization of Timgad through the lens of Space Syntax Analysis (SSA). Although SSA has proven effective for analyzing spatial configurations, its application to Roman colonial cities remains limited and theoretically underdeveloped. Scholars such as Quinn and Wilson [34] have cautioned against overemphasizing geometric regularity while overlooking the symbolic, ritual, and political dimensions embedded in spaces like fora and capitolia. Castagnoli [13] similarly argues that orthogonal planning in Roman cities was not merely a functional or military imposition but was deeply rooted in broader ideological frameworks. This concern echoes Jansen’s [35] critique regarding the methodological challenges of applying SSA to archaeological sites, where fragmentary data and uncertain reconstructions complicate interpretation. Garau et al. [36] advocate for a more holistic approach that integrates SSA with historical, epi-graphic, and architectural evidence to avoid reductionist outcomes. This research responds to such critiques by applying SSA not as a deterministic model, but as a heuristic framework capable of revealing spatial strategies of imperial control, while remaining attentive to the complexities of cultural, religious, and administrative functions in Roman urban design.

Over the past two decades, SSA has emerged as a versatile methodological frontier in archaeology [37]. Originally critiqued for its limited adaptability to socially diverse contexts, SSA has since evolved into a flexible “toolbox” approach [21,33], enabling researchers to explore patterns of access, movement, and visibility beyond purely stylistic analysis. Case studies from Roman contexts such as Ostia [33], Pompeii [38], and Empuries [33] highlight SSA’s capacity to uncover socio-spatial hierarchies yet also reveal concerns about architectural determinism and the abstraction of lived experience. The methodological caution raised by Fredrick and Vennarucci [37] emphasizes the need to calibrate syntactic findings with empirical, textual, and experimental data. Beyond Roman contexts, SSA’s adaptability is evident in studies of Mesopotamian settlements, Inuit architecture, and medieval networks [37], as well as in qualitative applications using access and j-graphs [39]. In Roman domestic architecture, SSA has exposed underlying structures of social privilege [21], yet remains subject to critiques for oversimplifying complex human behaviors [33]. Recent scholarship [40,41,42] reinforces the importance of integrating SSA with geophysical surveys and architectural analyses, underscoring that its strength lies in its capacity to complement rather than replace multi-scalar and reflexive archaeological interpretation.

This research aims to explore how Roman military strategy shaped the urban planning and spatial configuration of colonial cities, using Timgad as a case study. By applying SSA, this study seeks to decode the spatial logic embedded in the city’s grid-like urban fabric and to identify how it was strategically designed to reinforce Roman authority and control. The main goal is to reveal the extent to which Roman military priorities, such as surveillance, mobility, and territorial command, influenced Timgad’s layout, particularly through the arrangement of key structures along major roads and nodes. Finally, this study aims to demonstrate that Timgad’s urban form was not a neutral civic design but a deliberate spatial expression of military strategy, serving both as a model for Roman colonial cities and as evidence of the enduring impact of imperial spatial governance.

2. Presentation of the City of Timgad “Thamugadi”

Timgad, known in Latin as Colonia Marciana Traiana Thamugadi, was selected as a case study due to its special state of preservation and its personification of Roman urban standards (Figure 1). Situated in the northeastern reaches of the Aurès Mountains, in the territory historically known as Numidia, the city was known as a Roman colonia, an important status typically accorded to settlements established for retired Roman legionaries, particularly those who had served in campaigns across Africa Proconsularis. This “colony deduction” strategy was a cornerstone of Roman policy in North Africa, serving both military and administrative objectives by installing loyal veteran populations in strategic frontier zones [42,43].

Designed according to a strict orthogonal plan, Thamugadi initially covered an area of approximately 12 hectares, constructed around the classic Roman grid layout. Over time, the city experienced a sizable expansion, eventually covering around 90 hectares [44]. Its architectural assembly contained a valuable collection of monumental buildings central to Roman civic life: temples dedicated to various deities, a forum, basilicas, baths, a library, and a well-preserved theater. These features reflect the cultural and political imprint of Rome on the provincial landscape of inner Numidia. In 1982, the city was inscribed on the UNESCO World Heritage List in recognition of its urban coherence, state of conservation, and exemplary representation of Roman urbanism [12].

According to UNESCO, Timgad holds exceptional heritage value as a prime example of Roman town planning, showcasing the clear implementation of the orthogonal grid system typical of Roman colonial cities. It is celebrated for its remarkable state of preservation, including its forum, triumphal arch, theater, and extensive street network (Figure 2). Timgad illustrates the spread of Roman urbanism across the Empire and provides significant comprehension into the organization of space, society, and governance in Roman North Africa [12].

The shaping of Thamugadi reflects the fundamental principles of Roman urbanism, which adhered to a rational and hierarchical spatial logic. Roman city foundations were often located at the intersection of strategic military and economic considerations, whether along coastal routes or within the continental interior [45]. This spatial order began with a symbolic ritual: a priest traced the city’s outline using a plow fitted with a bronze plowshare, lifting it at the designated points for the city gates. At noon, standing at the city’s geometric center with arms extended toward the sun, the priest established the cardinal axes, determining the east–west orientation of the Decumanus Maximus, the principal thoroughfare [8].

Perpendicular to the Decumanus Maximus lies the Cardo Maximus, forming the basic framework of the city’s grid system. Secondary streets, known as cardines and decumani, branch off to define the regular urban blocks or insulae, which structured both residential and commercial life [8,46]. At the intersection of these main axes stands the forum, the civic core of the city. Serving as the center of administrative, judicial, and commercial activities, the forum symbolized the Roman supreme of a centralized, multifunctional public space. In Thamugadi, this spatial logic was not simply imaginary but materialized in stone, offering continuing testimony to the systematic approach of Roman colonial planning in inland Numidia.

3. Basic Military Principles of the Urban Organization of Timgad

Roman urbanism in the provinces cannot be reduced to a uniform model but instead reflects a versatile structure shaped by military organization, symbolic representation, and regional adaptation. As Yegül [47] observes the Roman forum, the spatial and symbolic core of cities like Thamugadi should be understood not only as a fixed architectural type but also as a dynamic civic space influenced by evolving patterns of use, power, and identity. In Thamugadi, the forum is located at the intersection of the Cardo Maximus and Decumanus Maximus, symbolizing both the geometric and ideological center of the city and housing key administrative, legal, and religious buildings [47].

The urban development of Colonia Marciana Traiana Thamugadi, modern-day Timgad, presents a compelling case study of Roman planning in inland Numidia. Founded in 100 CE during the reign of Emperor Trajan, the colony was established to settle Roman veterans, most likely from Legio III Augusta stationed nearby at Lambaesis. Its foundation responded to both strategic military priorities and the broader objective of consolidating Roman authority across Numidia’s frontier zone [38,48].

The layout of Thamugadi reveals the enduring imprint of Roman military logic on civilian planning. The orthogonal grid, commonly found in Roman colonies, echoed the layout of military camps (castra) and facilitated control, surveillance, and efficient circulation [38,39]. This grid was established through ritual foundation practices described in Roman agrimensorial treatises, in which a priest defined the cardinal axes and laid out the primary roads and insulae [8].

The east–west Decumanus and the north–south Cardo, typically paved, defined the urban core, often colonnaded and lined with shops and public buildings [47]. Although defensive walls were sometimes constructed, particularly in cities near volatile borders, many Roman colonies, such as Thamugadi, were initially unwalled, reflecting assurance in regional stability and imperial protection [49]. Fortifications were often added later in response to unstable military or political conditions.

Timgad’s organizations reproduced those of other Roman colonial foundations, featuring public facilities such as a theater, thermal complexes, latrines, and a library, a rare feature that reflects both cultural ambition and the Roman state’s investment in civility. These monuments consolidated the Roman vision of the city as a part of the Empire, integrating entertainment, hygiene, administration, and religion into the built environment.

Prominently, the city’s location was selected not only for strategic and military purposes but also for its access to water resources and trade routes, a decisive factor across much of the Roman Empire [50]. Aqueducts and cistern systems, such as those found in Thamugadi and other African cities like Lepcis Magna and Dougga, were essential infrastructural elements that supported urban life in semi-arid environments. At the same time, the symbolic placement of features such as statues, standards (signa), and monuments commemorating military victories helped shape the city’s iconography and collective memory [47].

Reviewed through recent research, the Roman forum is increasingly recognized as a polyvalent space that accommodated both imperial display and everyday practices. Yegül [47] emphasizes the multiplicity of its functions, from legal measures to civic customs, and its crucial role in shaping urban identity. Rather than viewing the forum as a static spatial entity defined solely by its architectural boundaries, recent interpretations highlight its performative and adaptive dimensions, which varied across different regions of the Empire.

Thamugadi’s forum, and the city, demonstrates the interaction between standardized Roman urban models and local adaptation. While it shares structural and spatial resemblances with other Roman colonies, such as Augusta Raurica and Cuicul (modern Djemila), each site reflects a conveyed balance between imperial ideology and regional particularities [38]. In sum, Thamugadi should be situated within the broader narrative of Roman urbanism: an imperial project that combined military strategy, civic functionality, symbolic authority, and spatial adaptability (Figure 3).

4. Methodological Framework

This study employs Space Syntax Analysis (SSA) as a methodological framework to investigate the spatial organization of the Roman colonial city of Timgad, with a particular emphasis on its military and strategic dimensions. Developed by Hillier and Hanson, SSA provides a robust suite of analytical tools, including DepthMapX (Version 10.08.00), the Space Syntax Toolkit (SST) (0.3.10), and Python libraries such as NetworkX (10.08.00), that enable the quantitative assessment of how built environments influence movement, accessibility, and spatial control [39], all of which are crucial components in Roman urban military planning. In DepthMapX (10.08.00), the radius parameter defines the analytical range around a point or axial line, shaping the calculation of spatial integration as a measure of centrality. For axial analysis, the software automatically generates the fewest number of straight lines necessary to cover all navigable spaces, following the minimum set reduction method. These axial lines represent the most direct and efficient paths within the urban fabric, capturing the underlying logic of spatial organization [51].

Unlike traditional archaeological approaches, this study addresses a significant gap by employing Space Syntax Analysis (SSA) to explore how Roman military strategy directly shaped urban morphology. The research integrates various analytical tools, including site plan modeling, field photography, and the generation of multiple axial maps [22]. The SSA methodology is applied in two stages: global spatial measures through axial analysis and local spatial characteristics via Visual Graph Analysis (VGA), both of which serve to model and interpret the street network and spatial structure of Timgad. This integrated digital workflow facilitates a nuanced syntactic reading of the city’s layout, offering new insights into the strategic and functional dimensions of Roman urban design [51].

In Timgad, a Roman city distinguished by its regular orthogonal grid layout, axial lines are employed to model both the primary and secondary street networks, including the cardo (north–south axis), decumanus (east–west axis), and the intersecting streets and alleys. These lines represent the longest sightlines and potential paths of movement across open urban spaces, effectively modeling the principal routes through which people navigated and perceived the city [22,51]. Axial analysis reveals the hierarchical structure of spatial accessibility, highlighting how public spaces were integrated and how civic and religious buildings were spatially centralized within the urban fabric. This analytical approach allows us to assess how Roman planners embedded visibility, movement potential, and spatial organization into the city’s form, reflecting their underlying military, political, and social intentions.

To complement this, Visibility Graph Analysis (VGA) is applied to capture visual perception from any given point in space. While axial analysis focuses on linear connectivity between movement paths, VGA highlights the perceived visual quality of spaces, essential for understanding orientation, surveillance, safety, and the experiential attractiveness of the urban environment. Together, axial and VGA methods provide a comprehensive syntactic reading of spatial dynamics in Timgad, combining configurational and perceptual dimensions of urban analysis [52].

Six Space Syntax Analysis (SSA) indicators are employed in this study: Connectivity, Integration, Entropy, Control Value (CV), Controllability, and Through Vision, each selected for its capacity to reveal key aspects of spatial logic in the Roman city of Timgad [53]. The use of these indicators is rooted in their effectiveness at exposing the strategic and functional dimensions embedded within the city’s orthogonal grid. Specifically, Connectivity and Integration reveal the most accessible and central streets, typically the cardo and decumanus, that were vital for military mobility and administrative efficiency. Control Value and Controllability measure the degree to which certain spaces manage access to adjacent areas, offering insight into spatial zoning, hierarchy, and surveillance mechanisms. Through Vision, which assesses inter-visibility between spaces, highlights visual corridors likely designed for monitoring, orientation, and defense. Entropy, on the other hand, measures the overall complexity and spatial organization of the network [53]. Together, these indicators offer a comprehensive reading of how Timgad’s spatial configuration supported the military discipline, civic control, and symbolic order central to Roman colonial urbanism.

Table 1. SSA indicators: formulae for calculations and their specific roles.

SSA Core Indicators	Formula for Calculation	Specific Role
Connectivity (C)	$C={\displaystyle \frac{E}{N}} \text{(1)}$ E = total number of edge connections (intersections) N = number of nodes (axial lines) 25 [29].	Examines the number of direct spatial links, helping to identify major movement corridors such as the cardo and decumanus. High connectivity indicates that a space is immediately accessible from many others.
Integration (I)	$I={\displaystyle \frac{n-1}{{\sum }_{i=1}^{n-1}{\sum }_{j=i+1}^{n}dij}} \text{(2)}$ n = total number of spaces dij = shortest topological distance between spaces i and j. [29]	Assesses the centrality and accessibility of spaces within the urban system, highlighting strategic areas for circulation and command. Higher integration values indicate greater centrality and ease of access.
Entropy (H)	$H=-\sum P\left(i\right)\log P\left(i\right) \text{(3)}$ p(i): probability associated with the connectivity of node i. [29]	Evaluates the distribution of movement and indicates whether the urban design encourages centralized control or more dispersed spatial access. High Entropy indicates a more evenly distributed structure; low Entropy suggests a strong hierarchy or centrality.
Control (CV)	$CV\left(x\right)={\sum }_{j\in N\left(x\right)}{\displaystyle \frac{1}{\mathrm{d}\mathrm{e}\mathrm{g}\left(Y\right)}} \text{(4)}$ N(x): the set of immediate neighbors (adjacent nodes) to node x. deg(y): the degree (number of connections) of node y. [51]	Identifies locations that govern movement options, such as gates, intersections, or key surveillance points, spaces where Roman authority could be most effectively exercised. This measures how much control node x exerts over its immediate neighbors; more specifically, how likely a movement to neighbor y depends on x.
Controllability	$Controllability\left(x\right)={\displaystyle \frac{CV\left(x\right)}{\mathrm{d}\mathrm{e}\mathrm{g}\left(x\right)}} \text{(5)}$ CV(x): control value as defined above. deg(x): degree of node x, representing its own connectivity [51].	Identifying the degree to which a given space can influence movement across the network. This normalization allows us to compare nodes with different levels of connectivity, identifying strategic nodes that, despite limited links, control highly dependent spaces, typical of gates, chokepoints, or command hubs in Roman military urban design.
Through Vision (T(i))	$T\left(i\right)={\sum }_{j\in V\left(i\right)}{\displaystyle \frac{1}{Dij}}.\theta ij \text{(6)}$ V(i) is the set of all visually connected nodes to i, Dij gives weight to closer visual connections (closer spaces have greater influence), θij captures the visibility extent, often simplified to 1 if full visibility exists [51].	Measures how visually connected a location is to nearby spaces, captures what can be seen through space, and advancing perceptions into surveillance and spatial awareness. High Through Vision indicates strong surveillance potential, visual access, and spatial dominance.

shows the formula of calculation and describes the specific role for each SSA indicator to investigate the spatial layout of the Roman colonial settlement of Timgad.

These indicators are calculated using grid-based and axial analysis methods, in which the urban fabric is modeled as a network of spatial lines or visual fields. Tools such as DepthMapX facilitate much of this analytical process, allowing scholars to visualize and quantify the spatial stimulus of architectural and urban structures [51]. By inserting these syntactic indicators within the archaeological and historical framework of Roman settlement, this methodology not only reveals the intentional planning logic underlying Timgad’s urban composition but also advances a broader interpretation of how Roman military strategy materialized through space. This integrative approach thus assists a more nuanced interpretation of Roman urbanism, highlighting the strategic interplay between spatial design, imperial authority, and long-term historical development.

Figure 4 shows the research workflow chart, including the literature review; research problem definitions; presentation of the case study; methodology; generation of axial and syntactic graphs; and interpretation of the results.

5. Results

5.1. Global Spatial Measures from Axial Analysis

This section focuses on the syntactic mapping of Timgad’s urban fabric to uncover how Roman military planning principles were embedded within the city’s orthogonal street network. By constructing spatial relationships through justified axial maps and syntactic graphs, the analysis reveals how spatial logic was deliberately applied to express military order and strategic control. These visual and analytical tools make it possible to trace the underlying spatial structure of the city, offering insight into how urban space was organized to fulfill both functional imperatives and ideological objectives.

The types of axes, main, secondary, and tertiary, have been differentiated to reflect the degree of accessibility and the spatial hierarchy among various urban facilities. Each node has been connected to the generated axes according to its actual position within the spatial fabric, following the principles of justified graph representation. This configuration enables a more accurate reflection of spatial relationships by considering both physical and visual continuities provided by the existing road network (Figure 5).

The Connectivity map ensuing from axial analysis reveals an intentionally structured urban fabric in Timgad, where the most linked axes correspond to the Decumanus Maximus and Cardo Maximus, the primary Roman roads intersecting at the forum (node 47). These axes function as the city’s primary structural elements, providing immediate access to key administrative, religious, and commercial landmarks, including the Capitolium (46), the library (45), and the market (50). This concentration of connectivity reflects Roman military planning principles, designed to ensure efficient internal mobility and enable rapid gathering or deployment if necessary. The orthogonal grid reinforces this logic, with regularly spaced streets that not only facilitate access but also enhance spatial surveillance and control.

The city adheres to a strict orthogonal grid, characteristic of Roman colonial planning, marked by dense intersections along the Cardo and Decumanus Maximus and a high number of smaller urban blocks. This layout generates peaks of connectivity, particularly at key junctions and around the forum. The average connectivity value of 5.5 indicates that each segment connects, on average, to approximately five others, consistent with expectations for a highly regular urban framework [13,35]. In contrast, comparative analyses of Roman cities such as Cosa, Nora, and Thuburbo Majus, which exhibit less rigid or more organic morphologies, show average connectivity values typically ranging between 3 and 5, reflecting a looser or hybrid grid structure [36]. A modern case study of the Al Fahidi historic district in Dubai, a semi-grid urban environment, reported an average connectivity of 4.56, with certain nodes reaching values of 8 in highly connected zones, yet none approaching Timgad’s maximum of 20, underscoring the exceptional integration of the Roman grid [54].

The Integration values, both at the local scale (R3) and global scale (HH), emphasize the forum zone and its adjacent streets as the most integrated components of Timgad’s urban fabric. This spatial centrality confirms the forum’s pivotal role in both the cognitive map of the city and its functional hierarchy. The concentration of high global integration (HH) within the orthogonal grid reflects Roman strategic urban design aimed at imposing order, establishing hierarchy, and projecting imperial authority through spatial dominance. The underlying military rationale is evident in the efficient accessibility of key urban nodes, which facilitated rapid coordination and response while also reinforcing symbolic power through prominent spatial positioning. At the local level, the R3 integration values highlight the well-integrated secondary streets around civic facilities such as baths and temples, indicating a layered spatial hierarchy that extended from centralized control to peripheral urban support systems.

Entropy analysis reveals a moderate-to-high variability in spatial configuration across Timgad, with the highest Entropy levels observed in the central grid, particularly at key crossroads and multifunctional urban blocks. These zones reflect a complex spatial structure characterized by a diversity of route choices and potential movement paths. Such complexity suggests an intentional design, aimed at balancing flexibility in circulation with the need for regulatory oversight, a strategy that facilitated both urban dynamism and military responsiveness. The presence of multiple route options in the core implies a deliberate spatial openness that accommodates diverse civic functions while preserving spatial control. Conversely, peripheral and extramural areas expose lower Entropy values, pointing out their limited functional diversity and diminished strategic significance. This spatial disparity highlights the centralized logic of Roman urbanism, where the center of the city performed as the connection of control, visibility, and coordinated mobility.

Control values are notably highest at critical intersections near the forum and surrounding civic institutions, reflecting the strategic spatial role of these nodes in mediating access between local streets and major thoroughfares. These high-control points function as urban chokepoints, consistent with Roman military doctrine, which emphasized spatial command through control of junctions and transitional zones. Nodes adjacent to the theater (17), southern baths (40), and library (45) exhibit moderate control values, indicating their design function in regulating movement toward public and communal facilities. This graduated hierarchy of control demonstrates how Roman planners embedded military rationality into the urban structure, ensuring that key spaces could supervise, filter, and structure movement, thereby reinforcing imperial authority and urban discipline.

The Controllability map further underscores the hierarchical nature of Timgad’s urban design by identifying streets that serve as key access distributors, particularly within the central orthogonal grid. High controllability values are concentrated along secondary axes radiating from the Decumanus Maximus and Cardo Maximus, especially near the market (50) and principal temples (35, 36). This prototype implies a carefully calibrated spatial logic, wherein intermediate streets facilitate access to core civic and religious spaces, thus supporting both military surveillance and administrative functionality. In comparison, the peripheral streets, particularly in the western and southern sectors, exhibit low controllability, indicating their decreased strategic significance and supporting the spatial discrimination of roles across the urban fabric. This structure reflects a dual objective: enabling fluid internal circulation while maintaining tight control over spaces of political, religious, and symbolic value, in line with Roman imperial urban doctrine.

The Integration R3 (local scale) and Integration HH (global scale), with averages of 2.098 and 1.633, respectively, underscore the high levels of spatial accessibility both within immediate urban settings and across the broader network, characteristics that are symbolic of Roman colonial planning, accenting directness and legibility. The Entropy score, averaging 2.166, reveals a moderate to high degree of spatial variability, indicating a well-balanced layout that integrates both predictability and choice in movement, contributing to urban vitality. The Control value, peaking at 3.796, identifies segments, particularly around the forum and along major axes, which exert significant influence over spatial flow, effectively functioning as chokepoints or mediating nodes. Meanwhile, the Controllability average of 0.299 points to the presence of strategically placed segments that act as key decision nodes within the urban network. When compared to other Roman settlements or orthogonally planned cities, where these indicators usually register lower averages, Timgad’s results show the exceptional symmetry and intentionality surrounding its urban design. These values strengthen Timgad’s role as a definitive example of Roman military–urban ideology, where clarity, control, and order converge in spatial form (Figure 6).

5.2. Global Spatial Measures from Visibility Graph Analysis VGA

In the Visibility Graph Analysis (VGA) scenario applied to Timgad, the Connectivity map reveals a clear and effective spatial hierarchy embedded within the orthogonal street grid characteristic of the Roman castrum (Figure 7). Maximum connectivity values are remarkably concentrated along the Decumanus Maximus and Cardo Maximus, which intersect at the forum (proximate to node 47), affirming that these axial streets were deliberately designed to enable fluid movement, clear communication, and rapid coordination across the urban layout. Peripheral streets and thoroughfares adjacent to key civic and military structures, including the Western Gate (1), the Eastern Baths (39), and the Theatre (17), also exhibit reasonable to high connectivity, underscoring a spatial logic intended to guarantee both accessibility and surveillance. This configuration of connectivity reflects the Roman military ethos, which prioritized internal coherence, strategic visibility, and the capacity for efficient urban mobilization. The arrangement not only supported functional operations but also reinforced imperial control through the intentional integration of key nodes into a highly legible spatial framework.

The Through Vision map supplements this interpretation by emphasizing the visual scope and surveillance capacity of Timgad’s urban surroundings. High Through Vision values are mostly assembled along the main axial corridors and within the central grid, principally surrounding the forum (node 47), the capitolium (46), and important public institutions such as the library (45) and temples (36, 35). This spatial pattern shows that Roman urban planners were not uniquely involved with assisting efficient movement, but also intentionally engineered visual fields to emphasize oversight, symbolic authority, and psychological control over space. However, peripheral zones, including the southern gates and the necropolis, exhibit lower levels of visual integration, aligning with their secondary functional roles within the spatial hierarchy. Taken together, the VGA findings underscore a dual logic underpinning Timgad’s urban configuration: one that simultaneously promotes mobility and ensures visual dominance, thereby aligning spatial design with the imperatives of military strategy and imperial administration (

Table 2. Axial and VGA Analysis attribute values.

Axial Analysis
Attribute	Minimum	Average	Maximum
Connectivity	1	5.530	20
Integration R3	0.785	2.098	3.599
Integration HH	0.830	1.633	3.089
Entropy	1	2.166	2.617
Control	0.208	1	3.796
Controllability	0.103	0.299	0.75
Visibility Graph Analysis “VGA”
Attribute	Minimum	Average	Maximum
Connectivity	14	541.009	2228
Through Vision	0	22658.2	252125

).

6. Discussion

6.1. Investigating Military Strategies Through Axial Analysis

Figure 8 illustrates the principal Space Syntax indicators, Connectivity, Integration (R3 and HH), Entropy, Control, and Controllability, which collectively offer a nuanced understanding of Timgad’s spatial configuration. The relatively high maximum (20) and average (5.53) Connectivity values indicate that several axial lines functioned as highly interconnected corridors, reinforcing their role as primary channels for circulation and communication. These are most likely aligned with the Cardo Maximus and Decumanus Maximus, intersecting at the forum, which operated as both the civic heart and a strategic military junction. The concentration of high Connectivity in this central zone underscores Roman priorities: ensuring efficient troop mobility, direct access to key institutional zones, and broad urban surveillance. This spatial logic aligns with broader Roman imperial objectives that fused urban functionality with military oversight, thereby embedding control within the physical fabric of the colonial city.

The orthogonal street network of Timgad features numerous segments converging on key nodes, such as the forum, colonnaded avenues, and major intersections, resulting in exceptionally high maximum Connectivity values. The regularity of the urban fabric, particularly the consistent 21 × 21 m insulae (blocks), supports a uniformly elevated average Connectivity compared to settlements with less rigid geometries. In contrast, Roman towns characterized by organic growth or partial orthogonal planning, such as Nora or Cosa, display irregular junctions and winding streets, leading to lower segment-to-segment intersection density and thus reduced average and maximum Connectivity. Similarly, even semi-grid modern historic districts, such as Al Fahidi in Dubai, maintain average Connectivity values in the range of four to five, with maximum values rarely exceeding eight, largely due to structural discontinuities. Timgad’s superior Connectivity metrics, therefore, reflect the deliberate and disciplined implementation of Roman colonial planning principles.

Timgad’s maximum Connectivity value of 20 and average of 5.53 stand out as significantly higher than those observed in comparable Roman towns such as Thuburbo Majus, Djemila, or even Pompeii, where average Connectivity typically ranges between 3.0 and 4.5. This disparity underscores the exceptional regularity and intersection density of Timgad’s urban fabric, distinctive features of Roman colonial planning. The clearly defined cardo–decumanus structure, combined with uniformly sized insulae, generates numerous short and highly interconnected axial segments, particularly in the vicinity of the forum and central thoroughfares.

The moderate Integration values, averaging 2.098 for Integration R3 (local) and 1.633 for Integration HH (global), suggest a spatial configuration that is both hierarchical and cohesive. These figures expose a deliberate urban design that eased accessibility at multiple scales, authorizing ordered circulation while preserving zones of tactical control. Such dual-layer accessibility is typical of Roman orthogonal planning, which intently reproduced the structure of military camps (castra) and was intended to support both efficient civic administration and military responsiveness. The Entropy score, with a moderate average of 2.166, indicates a well-balanced variety in spatial connections, suggesting that movement was deliberately distributed across the urban fabric to avoid congestion while reinforcing control over spatial flow.

Timgad’s Integration R3 (average 2.098) and Integration HH (average 1.633) show a spatial system that is well-integrated at both local and global scales. When related to other Roman settlements such as Ostia, Lambaesis, or Nîmes, Timgad demonstrates more established Integration values across its urban central. While in many ancient cities high Integration tends to cluster around city gates or central marketplaces, Timgad’s Integration is more regularly distributed, principally around the forum and intersecting axial routes. This spatial pattern supports egalitarian movement throughout the city and aligns with the rational logic of its military foundation, designed for both administrative efficiency and rapid internal mobility.

The Control (average: 1) and Controllability (average: 0.299) indicators offer additional insight into the spatial hierarchy embedded within Timgad’s urban design. These values reveal the presence of specific nodes that exert influence over multiple adjacent spaces, functioning as strategic access points or surveillance junctures. Elevated Control values, particularly near intersections and civic institutions, indicate a deliberate spatial arrangement aimed at overseeing and regulating movement. Such a configuration aligns with Roman military urbanism, where spatial dominance was achieved not only through physical occupation but also through calculated spatial structuring. These findings reinforce the central argument advanced in the abstract: that Roman military planning was systematically encoded into the city’s spatial syntax, enabling effective control through both visibility and access regulation.

Timgad’s maximum Control value (3.796) reflects a high degree of spatial dominance exerted by certain axial lines, most likely those connecting the city gates to the forum and other central institutions. The relatively high average Controllability (0.299), especially when compared to organically developed cities such as Volubilis or Bulla Regia, underscores a more centralized and predictable spatial system. In these less planned settlements, lower Controllability values point to dispersed movement patterns and reduced hierarchical coherence. By contrast, Timgad’s configuration demonstrates a consider spatial order aligned with the imperial Roman ethos of surveillance, regulation, and centralized control, supporting the city’s role as both a military and administrative instrument of empire.

The average Entropy value of 2.166 specifies that Timgad preserves a modest degree of spatial variability, balancing uniformity with complexity. In contrast to cities with highly irregular street configurations, such as Al-Fustat or Byzantine Antioch, where Entropy values manage to be significantly higher due to labyrinthine layouts, Timgad exhibits a more organized yet flexible arrangement. Simultaneously, it circumvents the severity of overly regular plans with very low Entropy, which can hinder adaptability. This equilibrium between predictability and diversity supports multifunctional urban life, enabling effective military oversight, administrative organization, and civilian accessibility within a coherent spatial framework.

6.2. Investigating Military Strategies Through Visibility Graph Analysis

Figure 9, which presents the results for Connectivity and Through Vision derived from the Visibility Graph Analysis (VGA), further substantiates the interpretation of Timgad’s spatial logic. The exceptionally high average and maximum Through Vision values (22,658.2 and 252,125, respectively) point to an urban layout characterized by expansive visual fields, particularly along the Cardo Maximus, Decumanus Maximus, and the forum area. These long and unobstructed sightlines were not just functional but intentionally engineered. Roman urban planners strategically labored visual access as a mechanism of authority, allowing continuous surveillance, ceremonial visibility, and psychological control over public space. The minimum Through Vision value of zero, conversely, denotes the existence of visually enclosed or isolated zones, likely corresponding to private dwellings or service quarters, thus reinforcing a spatial hierarchy in which visibility and openness were concentrated in politically, militarily, and economically significant areas.

The high VGA-based connectivity values (average: 541.009; maximum: 2228) underscore the strong inter-visibility between spatial units within Timgad’s urban grid. Such elevated levels of visual connectivity support the argument that the city was designed not only for lucidity and legibility but also for spatial supremacy. Free visual access played an essential role in sustaining social order, projecting imperial ideology, and facilitating the smooth operation of civic functions, particularly within a framework governed by Roman military authorities. Furthermore, the wide range observed between minimum and maximum values for both Connectivity and Through Vision points to a deliberate spatial stratification. Monumental and open areas intended for public engagement and spectacle coexist with more enclosed, private zones, all nested within a highly controlled and orthogonal layout. This layered spatial experience reflects the Roman capacity to harmonize ideological control with functional diversity.

Taken together, the data from both syntactic and visual analyses confirm that Timgad was far more than a typical Roman colonial outpost; it constituted a spatial articulation of imperial military logic. The integration of Space Syntax indicators and Visibility Graph Analysis reveals a calculated orchestration of movement and vision, core tools of Roman control. The forum’s strategic placement at the intersection of the Cardo and Decumanus, the rigor of orthogonal planning, and the deliberate modulation of accessibility and visual fields all attest to a nuanced spatial strategy aligned with broader mechanisms of imperial domination and cultural assimilation. As this research demonstrates, Roman military strategy extended beyond the battlefield, embedding itself in the morphology of urban space. Through SSA, these embedded strategies become legible, illustrating how the Roman ethos of order, surveillance, and control was inscribed into the very fabric of cities like Timgad, particularly in frontier provinces such as Numidia, where spatial design became an instrument of imperial consolidation.

7. Conclusions

The Space Syntax Analysis (SSA) of Timgad reveals the strategic intentionality behind Roman military urban planning, where spatial configuration was not incidental but deeply embedded in the logic of imperial governance. By employing syntactic tools such as axial maps and visibility graphs, this study uncovers the hierarchical organization and functional zoning that underpinned the city’s design. These analytical methods demonstrate how Timgad’s spatial structure supported multiple objectives, military oversight, civic administration, and social regulation, all within a unified urban framework. The findings affirm that defensive preparedness and urban functionality were not opposing priorities but rather coalesced through rational and disciplined spatial planning. Timgad exhibits Syntactic values, Connectivity, Integration, Control, and Visual reach, that are markedly higher and more centralized than those observed in many other Roman or orthogonal cities analyzed through SSA. As such, it stands as a paradigmatic example of Roman colonial urbanism, not only ideologically but morphologically, serving as a crucial reference in comparative urban morphology and in deciphering the spatial logic of Roman imperialism.

Based on SSA, several key military strategies can be identified from the Roman urban planning of Timgad:

• The Roman layout exhibits a clear spatial gradation from central axes (Cardo and Decumanus) to peripheral zones, ensuring that high-movement corridors also serve as key surveillance and military response routes;
• High Connectivity and high Integration streets facilitated rapid deployment and efficient movement of resources;
• Areas with high control values, often located at axial intersections, were chosen for military posts and surveillance units. This enabled visibility over large areas and monitoring of civilian movements;
• The Through Vision (visual connectivity) and Entropy indicators further confirm strategic visual command across the urban grid;
• Entrances were concentrated along the most integrated and accessible streets to maximize defensibility and control of entries;
• Peripheral walls and gates were planned in accordance with the spatial syntax of movement and control, reinforcing fortification strategies;
• The spatial structure supported centralized logistics, enabling efficient supply distribution to military and civic sectors through well-integrated corridors.

This research has significantly expanded the investigative framework, opening avenues for deeper exploration of the results. One promising direction implies determining the interconnections among Roman cities in the area neighboring Timgad, with the aim of valuing the potential complementarities in their military control mechanisms. Such an exploration to provide significant comprehension into the broader strategic logic of Roman urbanism in frontier provinces. Particularly, studying these inter-urban relationships may disclose forms of coordination, dependence, or mutual fortification among urban centers, extending new anthropological interpretations of shared military governance and regional defense strategies. This perspective would contribute to a more nuanced understanding of how Roman authority was spatially and militarily consolidated across North Africa.

While Space Syntax Analysis (SSA) offers valuable understandings into the spatial organization of Timgad, its application in this study reveals several methodological limitations. First, the absence of comparative analysis with other well-preserved Roman archaeological sites in Algeria, such as Djemila, Tipaza, and Lambaesis, limits the ability to contextualize Timgad’s spatial logic within broader regional urban prototypes. Second, the two-dimensional focus of the current analysis guides the vertical dimension of spatial experience. Incorporating a 3D reconstruction of the site would enable a more refined visibility analysis, particularly in understanding the role of building height and elevation in shaping spatial perception and control. Third, relying on a limited set of syntactic indicators constrains the scope of interpretation. A more complete approach that integrates supplementary metrics, such as Entropy, Control values, or Visual Integration, would fortify the robustness of the findings and expand their applicability to other Roman urban contexts, both regionally and across the broader Roman Empire. Lastly, SSA alone may not fully describe the alternative urban strategies or socio-political intentions inserted in Timgad’s orthogonal layout, leading to an overgeneralized reading of Roman spatial design and its layered meanings.