Analysis of Structures’ Orientations in Archaeoastronomy
Methods for the Quantitative Statistical Assessment of Peaks in Composite Probability Distributions
DOI:
https://doi.org/10.1558/jsa.18109Keywords:
azimuths and declinations, binomial distribution, composite SPDs, confidence envelope curve, geometric probability, structure orientationsAbstract
The study of structures’ orientations in archaeoastronomy often involves the analysis of the empirical sum of probability densities (SPD) for azimuths and declinations. A first logical step is to test the null hypothesis A of a random distribution of azimuths. This paper applies two methods: (1) the confidence envelope method with the azimuth SPD; and (2) binomial distribution with a probability parameter found from geometric estimates. Some empirical SPDs for which A is rejected can be composed of several subpopulations of structures with different grouping criteria. To assess the statistical significance of peaks or attractors potentially targeted to specific azimuths or declinations, a null hypothesis B is formulated. In its strong version, this hypothesis negates the existence of any attractor, while its weak version focuses on the local region of the peak without hypothesising about the rest of the SPD. This paper presents two methodologies for assessing B: (1) the method of the confidence envelope, applied to the strong version of B; and (2) a geometric method with the binomial distribution and a probability parameter estimated from the normalised frequency around the peak in the SPD (for the weak version of B). The methodology is illustrated with a case study of churches dedicated to the Virgin of the Assumption in southern Spain.
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References
Abril, J. M., 2017. “Evidence of Churches Aligned to the Sun on the Patron Saint’s Day in Southern Spain after the Twelfth Century”. Journal of Skyscape Archaeology 3 (1): 29–48. https://doi.org/10.1558/jsa.31508
Abril, J. M., 2020. “The Orientation of Gothic-Mudéjar Churches in Southern Spain: The Rotation of the Qibla and Sunrise on the Canonical Equinox”. Journal of Skyscape Archaeology 6 (2): 182–206. https://doi.org/10.1558/jsa.19629
Ali, J. R. and P. Cunich, 2001. “The Orientation of Churches: Some New Evidence”. Antiquaries Journal 81: 155–193. https://doi.org/10.1017/S0003581500072188
Allen, A. S., 2016. “Church Orientation in the Landscape: A Perspective from Medieval Wales”. Archaeological Journal 173 (1): 154–187. https://doi.org/10.1080/00665983.2016.1110781
Belmonte, J. A., M. Shaltout and M. Fekri, 2009. “Astronomy, Landscape and Symbolism: A Study of the Orientation of Ancient Egyptian Temples”. In In Search of Cosmic Order: Selected Essays on Egyptian Archaeoastronomy, edited by J. A. Belmonte and M. Shaltout, 215–283. Cairo: Supreme Council of Antiquities Press.
Bennett, G. G., 1982. “The Calculation of Astronomical Refraction in Marine Navigation”. Journal of Navigation 35 (2): 255–259. https://doi.org/10.1017/S0373463300022037
Bevington, P. A. and D. K. Robinson, 2003. Data Reduction and Error Analysis for the Physical Sciences (third edition). New York: McGraw-Hill.
Brady, B., D. Gunzburg and F. Silva, 2016. “The Orientation of Cistercian Churches in Wales: A Cultural Astronomy Case Study”. Citeaux: Commentarii Cistercienses 67 (3–4): 275–302.
Conferencia Episcopal Española, 2016. “Parroquias de cada diócesis” [online]. Accessed June 2016, http://www.conferenciaepiscopal.nom.es/parroquias/
Dal Zovo, C., A. C. González-García and Y. Seoane-Veiga, 2014. “Orientation of Bronze Age Mounds in Mongolian Altai Mountains”. Mediterranean Archaeology and Archaeometry 14 (3): 223–232.
Gil, S. and E. Rodríguez, 2001. Física re-creativa: Experimentos de Física usando nuevas tecnologías. Buenos Aires: Prentice Hall.
González-García, A. C. and J. A. Belmonte, 2014. “Sacred Architecture Orientation across the Mediterranean: A Comparative Statistical Analysis”. Mediterranean Archaeology and Archaeometry 14 (2): 95–113.
González-García, A. C. and J. A. Belmonte, 2015. “The Orientation of Pre-Romanesque Churches in the Iberian Peninsula”. Nexus Network Journal 17: 353–377. http://dx.doi.org/10.1007/s00004-014-0231-7
González-García, A. C., J. A. Belmonte and A. Polcaro, 2016. “A Diachronic Analysis of Orientation of Sacred Precincts across Jordan”. Mediterranean Archaeology and Archaeometry 16 (4): 133–141.
González-García, A. C., A. Rodríguez-Antón and J. A. Belmonte, 2014. “The Orientation of Roman Towns in Hispania: Preliminary Results”. Mediterranean Archaeology and Archaeometry 14 (3): 107–119.
Hinton, I. D., 2010. Aspects of the Alignment and Location of Medieval Rural Churches. PhD diss., University of East Anglia, UK.
Hughes I. G. and T. P. A. Hase, 2010. Measurements and their Uncertainties: A Practical Guide to Modern Error Analysis. Oxford: Oxford University Press.
IAPH [Instituto Andaluz del Patrimonio Historico, Consejeria de Cultura y Patrimonio Historico], 2020. Guia Digital del Patrimonio Cultural de Andalucía [online]. Accessed January 2020, https://guiadigital.iaph.es
IGN [Instituto Geografico Nacional], 2016. Iberpix Viewer [online]. Accessed March 2016. http://www.ign.es/iberpix2/visor
Kanisch, G., 2017. “Detection Limit Calculations for Peak Evaluation Methods in HPGe Gamma-Ray Spectrometry According to ISO 11929”. Nuclear Instruments and Methods in Physics Research, Section A 855: 118–132. https://doi.org/10.1016/j.nima.2017.02.092
Kosowsky, M., 2012. HeyWhatsThat [online]. Accessed November 2019, http://www.heywhatsthat.com/
Kräuchi, K., 2020. “How Has a Christian Church been Aligned Towards the East? Conclusions from Statistical Analyses of Churches Built Between 300 and 1300”. Archaeometry 63 (3): 668–683. https://doi.org/10.1111/arcm.12622
Magli, G., 2015. Archaeoastronomy: Introduction to the Science of Stars and Stones. New York: Springer.
Pérez Valcárcel, J. and V. Pérez Palmero, 2018. “La orientación de las iglesias mozárabes”. España Medieval 41: 171–197. http://dx.doi.org/10.5209/ELEM.60008
Silva, F., 2017. “Inferring Alignments I: Exploring the Accuracy and Precision of Two Statistical Approaches”. Journal of Skyscape Archaeology 3 (1): 93–111. https://doi.org/10.1558/jsa.31958
Silva, F., 2020. “A Probabilistic Framework and Significance Test for the Analysis of Structural Orientations in Skyscape Archaeology”. Journal of Archaeological Sciences 118: Article 105138. https://doi.org/10.1016/j.jas.2020.105138
Spinazzè, E., 2018. “De Quattuor Partibus Mundi. Medieval Sacred Buildings on the Via Francigena in Northern and Middle Italy: Solstice Alignments and Orientations”. Mediterranean Archaeology and Archaeometry 18 (4): 241–249. https://doi.org/10.5281/zenodo.1478694
Statgraphics Technologies, 2021. Statgraphics Centurion 18, 2017 [online]. Accessed January 2021, http://www.statgraphics.com
Szentmiklósi, L., 2018. “Fitting Special Peak Shapes of Prompt Gamma Spectra”. Journal of Radioanalytical and Nuclear Chemistry 315: 663–670. https://doi.org/10.1007/s10967-017-5589-z
Vogel, C., 1962. “Sol æquinoctialis. Problèmes et technique de l’orientation dans le culte chrétien”. In Archéologie paléochrétienne et culte chrétien, edited by M. Nedoncelle, B. Botte, L. De Bruyne, A. Grabar, R. Marichal, C. Mohrmann ans C. Vogel, 175–211. Special issue of Revue des Sciences Religieuses 36 (3–4). https://doi.org/10.3406/rscir.1962.2332
Zahn, G. S., F. A. Genezini and M. Moralles, 2009. “Evaluation of Peak-Fitting Software for Gamma Spectrum Analysis”. International Nuclear Atlantic Conference – INAC 2009. Río de Janeiro: ABEN [online]. Accessed January 2020, https://inis.iaea.org/collection/NCLCollectionStore/_Public/41/076/41076057.pdf
