BEGIN:VCALENDAR VERSION:2.0 PRODID:-//pretalx//talks.osgeo.org//foss4g-2026//speaker//KZQBHV BEGIN:VTIMEZONE TZID:JST BEGIN:STANDARD DTSTART:20000101T000000 RRULE:FREQ=YEARLY;BYMONTH=1 TZNAME:JST TZOFFSETFROM:+0900 TZOFFSETTO:+0900 END:STANDARD END:VTIMEZONE BEGIN:VEVENT UID:pretalx-foss4g-2026-UZ9V88@talks.osgeo.org DTSTART;TZID=JST:20260902T133000 DTEND;TZID=JST:20260902T140000 DESCRIPTION:The orientation of Christian churches has long attracted attent ion 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 Chris t’s return. In actual urban settings\, however\, church orientation is r arely determined by theology alone. Existing streets\, neighbouring buildi ngs\, plot geometry\, topography\, and later rebuilding campaigns can all shape the final disposition of a church building. This tension between sac red orientation and urban form makes church directionality a productive fi eld of inquiry at the intersection of religion\, architecture\, and urban studies.\n\nThis proposal investigates church orientation patterns in Mila n\, Italy\, using open geospatial data derived primarily from OpenStreetMa p (OSM). Milan is an appropriate case because it is a historic Catholic ci ty with a long continuity of ecclesiastical development and a complex urba n morphology shaped by Roman\, medieval\, early modern\, and modern transf ormations. 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.\n\nT his proposal also responds to a methodological opportunity. OSM has become an important infrastructure for transportation analysis\, humanitarian ma pping\, land use studies\, and urban modelling\, yet its value for archite ctural-historical and religious-spatial research remains underexplored. By using OSM building footprints as the spatial basis for city-scale analysi s\, this proposal contributes to an emerging dialogue between open geospat ial science\, digital humanities\, urban history\, and the study of religi on.\n\nPrevious scholarship has proposed several explanations for church o rientation. One long-standing interpretation emphasizes alignment toward g eographic East as a symbolic and liturgical norm. A second associates chur ch alignment with the sunrise azimuth on the feast day of the patron saint . A third suggests that deviations from true East may reflect the historic al use of magnetic compasses during church construction. In this debate\, Arneitz et al. (2014) provide an important reassessment based on a statist ical 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 Aust ria and −2.1° in northern Germany. By contrast\, deviations from magnet ic East were much larger\, at −19.0° and −14.0°\, leading the author s to reject the compass hypothesis statistically. They also found that the patron-saint sunrise model showed greater scatter and only limited explan atory value overall.\n\nEqually important\, Arneitz et al. argue that devi ations from East should not automatically be treated as evidence of altern ative symbolic rules. They emphasize that church orientation may be affect ed by neighbouring buildings\, pre-existing streets\, foundation condition s\, 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 sho uld therefore be understood as the result of both sacred principles and ma terial-spatial constraints. This framework is particularly useful for inte rpreting Milan\, where churches are situated within a dense and historical ly layered urban fabric.\n\nThe dataset used in this proposal consists of 114 church buildings in Milan. For each case\, a web-based mapping tool wa s developed using MapLibre GL JS and Turf.js to measure entrance orientati on 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 defi ned as the azimuth from the building centroid toward the main entrance. Al though this value does not directly measure the liturgical axis or altar o rientation\, 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 vi sualized through a wind rose diagram. For exploratory analysis\, the beari ngs were grouped into 16 directional sectors to evaluate concentration and dispersion.\n\nThe results show that church entrances in Milan are neithe r 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\, representi ng 16.7% of the sample. Together\, they account for one-third of all obser ved 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 stat istics 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.\n\nThese findings suggest that the t raditional Catholic arrangement of west-facing entrances and east-facing s anctuaries may still be partially visible in Milan at the aggregate level. At the same time\, the relatively low concentration and the presence of s ubstantial eastern and southwestern groups indicate that the city cannot b e explained by a single orientation rule. Instead\, Milan appears to conta in a mixed spatial morphology of church orientation. Some churches likely preserve the canonical east–west liturgical axis\, while others appear t o have adapted to street alignment\, constrained parcels\, public squares\ , topographic conditions\, or later phases of rebuilding and urban redevel opment.\n\nThis interpretation aligns closely with the implications of Arn eitz et al. (2014). Their work suggests that the most productive way to an alyse church orientation is not to choose between symbolic and practical e xplanations\, 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. En trance direction becomes a meaningful variable through which one can explo re the relationship between ecclesiastical architecture and surrounding ci ty form.\n\nMethodologically\, this proposal demonstrates the value of com bining OSM building geometries\, a custom open-source web mapping tool\, m anually validated directional attributes\, and circular analytical techniq ues in an open and reproducible workflow. The approach is lightweight and transferable to other cities where church inventories and building footpri nts are available. It also opens possibilities for comparative research ac ross Catholic and non-Catholic cities\, as well as diachronic analyses inc orporating construction dates\, denominational affiliation\, or street-net work orientation.\n\nThe contribution of this proposal is therefore twofol d. Substantively\, it offers new evidence that church orientation in Milan reflects both sacred tradition and urban form. Methodologically\, it show s that open geospatial data\, OSM-based analysis\, and openly released ana lytical tools can extend church orientation research beyond isolated monum ents toward city-scale spatial humanities. In the context of FOSS4G and IS PRS-related academic discussion\, the study demonstrates how open mapping ecosystems can support new forms of interdisciplinary scholarship across r eligion\, architecture\, urban history\, and geospatial science. DTSTAMP:20260718T211456Z LOCATION:Cosmos2 SUMMARY:Between Sacred Tradition and Urban Form: An OpenStreetMap-Based Ana lysis of Church Orientation Patterns in Milan - Taichi Furuhashi\, Hinako Terado URL:https://talks.osgeo.org/foss4g-2026/talk/UZ9V88/ END:VEVENT END:VCALENDAR