This study aims to evaluate the walkability of the area surrounding Shin-Yurigaoka Station for older adults, which is located in a hilly, suburban environment. This will be achieved by analysing the street network as a whole using a gradient-aware network approach.

In Japan, walkability has become an increasingly important issue in the context of rapid population ageing. Older adults continue to go out frequently in their daily lives and walking remains one of their main modes of travel. In this context, the ease of walking is shaped not only by distance or network connectivity, but also by the physical burden of slopes. This issue is particularly relevant in Japanese suburban hilly areas, where many residential districts have been developed on hilly terrain, often requiring residents to negotiate slopes and stairways to access stations, shops, and everyday services.

Against this background, this study focuses on the area around Shin-Yurigaoka Station in Asao Ward, Kawasaki City, examining how the walkability of older adults can be understood through a combined perspective of street network structure and slope conditions. Asao Ward is an appropriate study area for two reasons. Firstly, according to the 2020 Municipal Life Tables published in 2023, Asao Ward had the highest average life expectancy in Japan for both men and women, making it a notable area for longevity. Secondly, despite its hilly terrain, a Kawasaki City survey found that a significant proportion of older residents in the ward reported being able to walk for around 15 minutes or doing so in their daily lives. This suggests that walking remains an important mode of everyday mobility for older adults, even in areas with many slopes.

This raises a key analytical question: in hilly urban environments, do roads that are structurally central to the street network also function as physically walkable routes for older adults? To address this question, the study examines the degree of overlap between network centrality and low-slope conditions.

In Space Syntax research, configurational measures such as Integration have been linked to pedestrian movement (Hillier et al., 1993). In contrast, walkability is understood to be a multidimensional concept influenced not only by road connectivity, but also by factors such as access to destinations, land use and safety (Saelens & Handy, 2008). Studies of older adults have also shown that walking and physical activity are influenced by neighbourhood environmental factors, including walkability, access to destinations, and pedestrian infrastructure (Barnett et al., 2017). These findings suggest that street-network centrality alone may not fully explain actual walkability, particularly in hilly areas. Therefore, this study introduces a gradient-aware network analysis that integrates street-network centrality with topographic conditions.

The analysis was conducted using open geospatial data and open-source software. Road network data were obtained from OpenStreetMap and a 5-metre digital elevation model (DEM) was used to represent topography. To better focus on walkable public routes, roads classified as parking areas, private roads and indoor roads were excluded from the analysis. The study area was defined as a 15-minute walking catchment around Shin-Yurigaoka Station, based on an assumed walking speed of 1.0 m/s for older adults. In QGIS, the roads were divided into 10 m segments and the longitudinal gradient of each segment was calculated based on the elevation difference between its start and end points. In parallel, Integration values were derived through Angular Segment Analysis at a radius of 900 m (R900) using DepthmapX and the Space Syntax Toolkit. These values were then assigned to road segments at intersections. Integrating these variables enabled the study to construct a gradient-aware network analysis framework, evaluating each road segment in terms of its configurational importance within the overall network and walking difficulty due to slope.

The results reveal several important patterns. Within the 15-minute walking catchment area of Shin-Yurigaoka Station, high-integration roads — defined as the top 20% of the network in terms of integration value — accounted for 23.9% of the total road length. Low-gradient roads, defined as having a gradient of 8.0% or less based on Japanese sidewalk design standards, accounted for 84.7% of the total. Roads that satisfied both conditions simultaneously — namely, roads that were both highly integrated and low in gradient — accounted for 21.6% of the total. Examining the intersection of these two conditions more closely, it was found that 90.8% of high-integration roads were also low-gradient roads. This suggests that many of the structurally central roads around the station have relatively gentle slopes. In contrast, only 25.6% of low-gradient roads were classified as highly integrated. This suggests that, while gentle-slope roads are widely distributed across the study area, they do not necessarily form the core of the street network.

These findings suggest that the walkability of a hilly urban area for older adults should be evaluated not only in terms of the physical ease of the slope, but also in terms of the role that a road plays within the overall network. In other words, roads that are easy to walk on do not necessarily occupy a central or strategic position in everyday movement patterns. This is an important consideration when it comes to understanding mobility in suburban hilly areas, where the topography can reshape the relationship between urban structure and practical pedestrian accessibility. The study also demonstrates the value of using open street and elevation data alongside open-source spatial analysis tools to examine this issue from a reproducible and scalable perspective.

As a next step, road data in OpenStreetMap and QGIS will be refined to ensure the analytical network more accurately reflects the actual pedestrian environment, including sidewalks and other walkable links. The analysis will also be extended to a 30-minute walking catchment area to compare the relationship between centrality and gradient at a broader spatial scale. Furthermore, future work will validate the gap between the analytical results and the actual physical environment in order to examine the validity and applicability of gradient-aware network analysis for evaluating walkability for older adults in hilly urban areas.

The orientation of Christian churches has long attracted attention in liturgical studies, architectural history, and archaeoastronomy. In the Catholic tradition, churches are often associated with an eastward-facing sanctuary and a westward-facing entrance, reflecting theological symbolism linked to sunrise, resurrection, and the anticipation of Christ’s return. In actual urban settings, however, church orientation is rarely determined by theology alone. Existing streets, neighbouring buildings, plot geometry, topography, and later rebuilding campaigns can all shape the final disposition of a church building. This tension between sacred orientation and urban form makes church directionality a productive field of inquiry at the intersection of religion, architecture, and urban studies.

This proposal investigates church orientation patterns in Milan, Italy, using open geospatial data derived primarily from OpenStreetMap (OSM). Milan is an appropriate case because it is a historic Catholic city with a long continuity of ecclesiastical development and a complex urban morphology shaped by Roman, medieval, early modern, and modern transformations. Rather than treating churches only as isolated monuments, this study approaches them as urban objects embedded in streets, blocks, and neighbourhood structures. It asks three questions: first, whether church entrances in Milan display a statistically visible directional pattern; second, whether that pattern suggests the persistence of the traditional east–west liturgical axis; and third, how directional variation can be interpreted in relation to urban morphology and spatial constraints.

This proposal also responds to a methodological opportunity. OSM has become an important infrastructure for transportation analysis, humanitarian mapping, land use studies, and urban modelling, yet its value for architectural-historical and religious-spatial research remains underexplored. By using OSM building footprints as the spatial basis for city-scale analysis, this proposal contributes to an emerging dialogue between open geospatial science, digital humanities, urban history, and the study of religion.

Previous scholarship has proposed several explanations for church orientation. One long-standing interpretation emphasizes alignment toward geographic East as a symbolic and liturgical norm. A second associates church alignment with the sunrise azimuth on the feast day of the patron saint. A third suggests that deviations from true East may reflect the historical use of magnetic compasses during church construction. In this debate, Arneitz et al. (2014) provide an important reassessment based on a statistical analysis of medieval churches in Lower Austria and northern Germany. Their study compares deviations from geographic East, magnetic East, and sunrise azimuths associated with patrons’ feast days. The smallest mean deviations were found relative to geographic East: −5.5° in Lower Austria and −2.1° in northern Germany. By contrast, deviations from magnetic East were much larger, at −19.0° and −14.0°, leading the authors to reject the compass hypothesis statistically. They also found that the patron-saint sunrise model showed greater scatter and only limited explanatory value overall.

Equally important, Arneitz et al. argue that deviations from East should not automatically be treated as evidence of alternative symbolic rules. They emphasize that church orientation may be affected by neighbouring buildings, pre-existing streets, foundation conditions, vegetation, and topography, especially in urban settings. They also note that a raised horizon can substantially shift the apparent sunrise, complicating straightforward solar interpretations. Church orientation should therefore be understood as the result of both sacred principles and material-spatial constraints. This framework is particularly useful for interpreting Milan, where churches are situated within a dense and historically layered urban fabric.

The dataset used in this proposal consists of 114 church buildings in Milan. For each case, a web-based mapping tool was developed using MapLibre GL JS and Turf.js to measure entrance orientation and automatically analyse church directionality. The analysis tool has been released as open-source software under the CC0-1.0 license, and the resulting measurements were organized in a spreadsheet. Direction was defined as the azimuth from the building centroid toward the main entrance. Although this value does not directly measure the liturgical axis or altar orientation, it provides a consistent and scalable proxy for analysing the public-facing directionality of church buildings in relation to the urban fabric. The azimuth values were analysed using circular statistics and visualized through a wind rose diagram. For exploratory analysis, the bearings were grouped into 16 directional sectors to evaluate concentration and dispersion.

The results show that church entrances in Milan are neither uniformly distributed nor tightly concentrated around a single bearing. Instead, the pattern is dispersed but structured. The wind rose reveals a noticeable concentration in the western to west-southwestern sectors. The two most frequent classes are W and WSW, each with 19 cases, representing 16.7% of the sample. Together, they account for one-third of all observed entrance directions. Secondary peaks appear in the E sector, with 12 cases (10.5%), and in the SW sector, with 11 cases (9.6%). Circular statistics yield a mean direction of 245.4° and a mean resultant length of 0.283, indicating a relatively weak but visible directional tendency rather than a strongly concentrated system.

These findings suggest that the traditional Catholic arrangement of west-facing entrances and east-facing sanctuaries may still be partially visible in Milan at the aggregate level. At the same time, the relatively low concentration and the presence of substantial eastern and southwestern groups indicate that the city cannot be explained by a single orientation rule. Instead, Milan appears to contain a mixed spatial morphology of church orientation. Some churches likely preserve the canonical east–west liturgical axis, while others appear to have adapted to street alignment, constrained parcels, public squares, topographic conditions, or later phases of rebuilding and urban redevelopment.

This interpretation aligns closely with the implications of Arneitz et al. (2014). Their work suggests that the most productive way to analyse church orientation is not to choose between symbolic and practical explanations, but to examine how these forces interact. In Milan, church entrances should therefore be read not only as liturgical markers but also as indicators of how sacred buildings negotiate the urban environment. Entrance direction becomes a meaningful variable through which one can explore the relationship between ecclesiastical architecture and surrounding city form.

Methodologically, this proposal demonstrates the value of combining OSM building geometries, a custom open-source web mapping tool, manually validated directional attributes, and circular analytical techniques in an open and reproducible workflow. The approach is lightweight and transferable to other cities where church inventories and building footprints are available. It also opens possibilities for comparative research across Catholic and non-Catholic cities, as well as diachronic analyses incorporating construction dates, denominational affiliation, or street-network orientation.

The contribution of this proposal is therefore twofold. Substantively, it offers new evidence that church orientation in Milan reflects both sacred tradition and urban form. Methodologically, it shows that open geospatial data, OSM-based analysis, and openly released analytical tools can extend church orientation research beyond isolated monuments toward city-scale spatial humanities. In the context of FOSS4G and ISPRS-related academic discussion, the study demonstrates how open mapping ecosystems can support new forms of interdisciplinary scholarship across religion, architecture, urban history, and geospatial science.