{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T14:29:50Z","timestamp":1774621790422,"version":"3.50.1"},"reference-count":61,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T00:00:00Z","timestamp":1774569600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia, I.P\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t              https:\/\/ror.org\/00snfqn58","award":["UID\/05105\/2025"],"award-info":[{"award-number":["UID\/05105\/2025"]}]},{"name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia, I.P\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t              https:\/\/ror.org\/00snfqn58","award":["UID\/04008\/2025"],"award-info":[{"award-number":["UID\/04008\/2025"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Heritage"],"abstract":"<jats:p>Underwater cultural heritage represents a fragile and largely unexplored component of historical landscapes, particularly in dynamic fluvial and coastal environments. Despite increasing international attention to its protection, the spatial identification of submerged heritage remains methodologically challenging. This study proposes a geo-historical approach that integrates historical cartography and Geographic Information Systems (GIS) to identify areas of high archaeological potential in underwater contexts. Focusing on the Douro River in Porto (Portugal), a UNESCO World Heritage city with a long maritime and fluvial history, the research analyses a set of key historical maps from the eighteenth and nineteenth centuries, complemented by documentary and archaeological sources. These cartographic materials were georeferenced and critically assessed in QGIS, enabling the digitisation of features associated with land\u2013water interaction, navigation hazards, port infrastructures, and military defences. The resulting spatial dataset was used to generate an interpretative map and a kernel density model highlighting potential underwater heritage hotspots along the riverbed and riverbanks. The findings identify several priority zones, including the river mouth, historic quays, former shipbuilding areas, and sectors linked to nineteenth-century defensive structures. While the study does not include in situ verification, it demonstrates the value of historical maps as predictive tools for guiding targeted underwater surveys and proposes a transferable, cost-effective framework for heritage prospection and management in historically active fluvial\u2013estuarine settings.<\/jats:p>","DOI":"10.3390\/heritage9040132","type":"journal-article","created":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T12:45:53Z","timestamp":1774615553000},"page":"132","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Historical Maps as a Tool for Underwater Cultural Heritage Recognition"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1277-3700","authenticated-orcid":false,"given":"Isabel Vaz de","family":"Freitas","sequence":"first","affiliation":[{"name":"REMIT\u2014Research on Economics, Management and Information Technologies, Portucalense University, Rua Dr. Ant\u00f3nio Bernardino de Almeida 541, 4200-072 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0306-6449","authenticated-orcid":false,"given":"Joaquim","family":"Flores","sequence":"additional","affiliation":[{"name":"CIAUD-UPT, Branch of CIAUD Research Centre for Architecture, Urbanism and Design, Department of Architecture and Multimedia Gallaecia, Universidade Portucalense, Rua Dr. Ant\u00f3nio Bernardino de Almeida 541, 4200-072 Porto, Portugal"},{"name":"CIAUD, Research Centre for Architecture, Urbanism and Design, Lisbon School of Architecture, Universidade de Lisboa, Rua S\u00e1 Nogueira, Polo Universit\u00e1rio do Alto da Ajuda, 1349-063 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3064-1514","authenticated-orcid":false,"given":"Helena","family":"Albuquerque","sequence":"additional","affiliation":[{"name":"REMIT\u2014Research on Economics, Management and Information Technologies, Portucalense University, Rua Dr. Ant\u00f3nio Bernardino de Almeida 541, 4200-072 Porto, Portugal"},{"name":"GOVCOPP\u2014Research Unit on Governance, Competitiveness and Public Policies, University of Aveiro, 3810-193 Aveiro, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,27]]},"reference":[{"key":"ref_1","unstructured":"UNESCO (2026, March 23). Conven\u00e7\u00e3o Para a Prote\u00e7\u00e3o do Patrim\u00f3nio Cultural Subaqu\u00e1tico. Available online: https:\/\/www.icomos.pt\/images\/pdfs\/2021\/43%20Conven%C3%A7%C3%A3o%20patrim%C3%B3nio%20subaqu%C3%A1tico%20-%20UNESCO%202001.pdf."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Perez-Alvaro, E. (2019). Underwater Cultural Heritage: Ethical Concepts and Practical Challenges, Routledge, Taylor & Francis Group.","DOI":"10.4324\/9780429467820"},{"key":"ref_3","unstructured":"(2025, December 23). Declara\u00e7\u00e3o de Tunes. Available online: https:\/\/starq.info\/info-legais\/leg-patrimonio-arqueologia\/cartas-e-convencoes-internacionais-sobre-patrimonio."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2676","DOI":"10.3390\/heritage4040151","article-title":"Underwater Cultural Heritage as an Engine for Social, Economic and Cultural Development. State of Research at the University of Cadiz (Andalusia, Spain)","volume":"4","year":"2021","journal-title":"Heritage"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1186\/s40494-022-00645-1","article-title":"Extraction of underwater fragile artifacts: Research status and prospect","volume":"10","author":"Chen","year":"2022","journal-title":"Herit. Sci."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1590\/S0101-90742008000200004","article-title":"Entre o uso social e o abuso comercial: As percep\u00e7\u00f5es do patrim\u00f4nio cultural subaqu\u00e1tico no Brasil","volume":"27","author":"Rambelli","year":"2008","journal-title":"Hist\u00f3ria"},{"key":"ref_7","unstructured":"Tripati, S. (2015). The 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage. Shipwrecks Around the World. The Revelation of the Past, Kaveri Books, Delta Public House."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"106782","DOI":"10.1016\/j.marpol.2025.106782","article-title":"Synergies between underwater cultural heritage and biodiversity conservation in Iceland: Insights for achieving 30 \u00d7 30 targets","volume":"180","author":"Edvardsson","year":"2025","journal-title":"Mar. Policy"},{"key":"ref_9","unstructured":"Kaya, D.I., Guzman, P., Veiga-Pires, C., Oliveira, S., Katika, T., Hoogbergen, A.V., Pulles, K., and Nicu, I.C. (2024, January 14\u201319). Living Labs for participatory value, risk and impact assessments in coastal and underwater heritage sites (No. EGU24-3132). Proceedings of the Copernicus Meetings, Vienna, Austria."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Ferrero-Mart\u00edn, C., Izquierdo, A., Bethencourt, M., and Fern\u00e1ndez-Montblanc, T. (2025). A Risk Assessment of Underwater Cultural Heritage for Wave-Induced Hazards: The Impact of Climate Change on Cadiz Bay. J. Mar. Sci. Eng., 13.","DOI":"10.3390\/jmse13010136"},{"key":"ref_11","unstructured":"Intergovernmental Panel on Climate Change (IPCC) (2021). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report, Cambridge University Press. Available online: https:\/\/www.ipcc.ch\/report\/ar6\/wg1\/."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Intergovernmental Panel on Climate Change (IPCC) (2022). Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report, Cambridge University Press. Available online: https:\/\/www.ipcc.ch\/report\/ar6\/wg2\/.","DOI":"10.1017\/9781009325844"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"146470","DOI":"10.1016\/j.scitotenv.2021.146470","article-title":"Sea level rise impacts on estuarine dynamics: A review","volume":"780","author":"Khojasteh","year":"2021","journal-title":"Sci. Total Environ."},{"key":"ref_14","first-page":"57","article-title":"Are underwater archaeological parks good for fishes? Symbiotic relation between cultural heritage preservation and marine conservation in the Azores","volume":"21","author":"Garcia","year":"2018","journal-title":"Reg. Stud. Mar. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Bruno, F., Ricca, M., Lagudi, A., Kalamara, P., Manglis, A., Fourkiotou, A., Papadopoulou, D., and Veneti, A. (2020). Digital Technologies for the Sustainable Development of the Accessible Underwater Cultural Heritage Sites. J. Mar. Sci. Eng., 8.","DOI":"10.3390\/jmse8110955"},{"key":"ref_16","first-page":"35","article-title":"Tourism and Algarve\u2019s Underwater Heritage Valorisation. A Case Study","volume":"XI","author":"Nunes","year":"2014","journal-title":"J. Marit. Res."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Ricca, M., Alexandrakis, G., Bonazza, A., Bruno, F., Davidde Petriaggi, B., Elkin, D., Lagudi, A., Nicolas, S., Nov\u00e1k, M., and Papatheodorou, G. (2020). A Sustainable Approach for the Management and Valorization of Underwater Cultural Heritage: New Perspectives from the TECTONIC Project. Sustainability, 12.","DOI":"10.3390\/su12125000"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1777","DOI":"10.1007\/s13280-023-01838-z","article-title":"Utilizing historical maps in identification of long-term land use and land cover changes","volume":"52","author":"Kivinen","year":"2023","journal-title":"Ambio"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"194","DOI":"10.1080\/00087041.2022.2150367","article-title":"From historical maps to remote sensing: Reconstructing land use changes on Norfolk Island over the past 250 years","volume":"60","author":"Levin","year":"2023","journal-title":"Cartogr. J."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"437","DOI":"10.1007\/s10761-024-00760-8","article-title":"Mapping Mauritius\u2019 Underwater Cultural Heritage: A GIS-Based Approach to Integrating Environmental Historical Archaeology and Heritage Management","volume":"29","author":"Manfio","year":"2024","journal-title":"Int. J. Hist. Archaeol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1017\/S0145553200011639","article-title":"Introduction to Historical GIS and the Study of Urban History","volume":"35","author":"DeBats","year":"2011","journal-title":"Soc. Sci. Hist."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"638","DOI":"10.1177\/0309132507081495","article-title":"Historical GIS: Structuring, mapping and analysing geographies of the past","volume":"31","author":"Gregory","year":"2007","journal-title":"Prog. Hum. Geogr."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Knowles, A.K., and Hillier, A. (2008). Placing History: How Maps, Spatial Data, and GIS Are Changing Historical Scholarship, ESRI Press.","DOI":"10.14714\/CP63.160"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1186\/s40494-024-01400-4","article-title":"Mapping the past with historical geographic information systems: Layered characteristics of the historic urban landscape of Nanjing, China, since the Ming Dynasty (1368\u20132024)","volume":"12","author":"Bai","year":"2024","journal-title":"Herit. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1007\/s12665-025-12260-x","article-title":"Reconstructing urban landscape evolution with historical maps and geophysical techniques: 3D time-sensitive and multi-source geomodelling","volume":"84","author":"Ciampi","year":"2025","journal-title":"Environ. Earth Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"69","DOI":"10.5194\/ica-proc-4-69-2021","article-title":"Content-based Image Retrieval for Map Georeferencing","volume":"4","author":"Luft","year":"2021","journal-title":"Proc. ICA"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"119","DOI":"10.17645\/up.v6i3.4017","article-title":"Morphological Evolution of the Port-City Interface of Algiers (16th Century to the Present)","volume":"6","author":"Aouissi","year":"2021","journal-title":"Urban Plan."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"32742","DOI":"10.1038\/s41598-025-05539-3","article-title":"AI methods for enhancing and recognizing archaeological features in heterogeneous geophysical datasets","volume":"15","author":"Danese","year":"2025","journal-title":"Sci. Rep."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Kadhim, I., and Abed, F.M. (2023). A Critical Review of Remote Sensing Approaches and Deep Learning Techniques in Archaeology. Sensors, 23.","DOI":"10.3390\/s23062918"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1269","DOI":"10.1007\/s11457-025-09477-z","article-title":"Predictive modeling of historical shipwreck locations in Lake Ontario using machine learning","volume":"20","author":"Conolly","year":"2025","journal-title":"J. Marit. Archaeol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1163\/16000390-09401044","article-title":"Predictive Modelling in Underwater Archaeology. A Case Based on Mesolithic Coastal Settlements in Denmark","volume":"94","author":"Giatsiatsou","year":"2024","journal-title":"Acta Archaeol."},{"key":"ref_32","unstructured":"Ritondale, E. (2022). Shipwrecking Probability in Mediterranean Territorial Waters: A Cultural Approach to Archaeological Predictive Modelling. [Doctoral Dissertation, IMT School for Advanced Studies Lucca]."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4678","DOI":"10.3390\/heritage4040258","article-title":"Development of Predictive Geoarchaeological Models to Locate and Assess the Preservation Potential of Submerged Prehistoric Sites Using Remote Sensing, Palaeoenvironmental Analysis, and GIS","volume":"4","author":"Gregory","year":"2021","journal-title":"Heritage"},{"key":"ref_34","first-page":"98","article-title":"Los SIG aplicados al estudio del Paisaje Cultural Mar\u00edtimo: Colonia del Sacramento desde el siglo XVII al XX","volume":"67","author":"Dourteau","year":"2021","journal-title":"Papeles Geogr."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"135","DOI":"10.4995\/var.2022.16917","article-title":"Aplicaci\u00f3n de un SIG a la arqueolog\u00eda subacu\u00e1tica de Menorca","volume":"13","year":"2022","journal-title":"Virtual Archaeol. Rev."},{"key":"ref_36","first-page":"43","article-title":"A Carta de Patrim\u00f3nio Arqueol\u00f3gico do PDM do Porto: Possibilidades e limites de uma cartografia da mem\u00f3ria e mutabilidade da cidade. Parte II\u2013Para al\u00e9m do Centro Hist\u00f3rico","volume":"45","author":"Gomes","year":"2024","journal-title":"Portvgalia"},{"key":"ref_37","unstructured":"(2025, October 02). Padre Agostinho Rebelo da Costa, Descri\u00e7\u00e3o Topogr\u00e1fica e Hist\u00f3rica da Cidade do Porto, Lisboa. Available online: https:\/\/purl.pt\/22517\/4\/res-2031-p_PDF\/res-2031-p_PDF_24-C-R0150\/res-2031-p_0000_capa-capa_t24-C-R0150.pdf."},{"key":"ref_38","unstructured":"Costa, L.F., and Sousa, R.M. (2018). O Porto e o seu Termo: Uma Hist\u00f3ria Econ\u00f3mica, Fronteira do Caos."},{"key":"ref_39","first-page":"437","article-title":"La Georreferenciaci\u00f3n de Cartograf\u00eda Antigua en los Sistemas de Informaci\u00f3n Geogr\u00e1ficos (SIG): Revisi\u00f3n, An\u00e1lisis y Estudio comparativo de Softwares de Georreferenciaci\u00f3n","volume":"31","year":"2021","journal-title":"Rev. Gen. Inf. Doc."},{"key":"ref_40","unstructured":"Dire\u00e7\u00e3o-Geral do Territ\u00f3rio (2025, September 10). Ortofotomapas 2021 (Web Map Service), Available online: https:\/\/cartografia.dgterritorio.gov.pt\/wms\/ortos2021."},{"key":"ref_41","unstructured":"Baumann, J., Fleischhacker, D., Goederle, W., Kamp, N., and Kern, R. (2025, January 2\u20133). Automated Segmentation of Historical Cadastral Maps: A Machine Learning Approach to the Franziszeischer Kataster. Proceedings of the AGIT Conference, Salzburg, Austria."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Uhl, J.H., Leyk, S., Chiang, Y.-Y., and Knoblock, C.A. (2022). Towards the automated large-scale reconstruction of past road networks from historical maps. arXiv.","DOI":"10.1016\/j.compenvurbsys.2022.101794"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2888","DOI":"10.1111\/tgis.12794","article-title":"Automatic content-based georeferencing of historical topographic maps","volume":"25","author":"Luft","year":"2021","journal-title":"Trans. GIS"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"402","DOI":"10.1016\/j.cag.2011.01.005","article-title":"Studying cartographic heritage: Analysis and visualization of geometric distortions","volume":"35","author":"Jenny","year":"2011","journal-title":"Comput. Graph."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"102060","DOI":"10.1016\/j.compenvurbsys.2023.102060","article-title":"A novel framework for road vectorization and classification from historical maps based on deep learning and symbol painting","volume":"108","author":"Jiao","year":"2024","journal-title":"Comput. Environ. Urban Syst."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1080\/01615440.2024.2324163","article-title":"Built-up areas of nineteenth-century Britain. An integrated methodology for extracting high-resolution urban footprints from historical maps","volume":"57","author":"Litvine","year":"2024","journal-title":"Hist. Methods J. Quant. Interdiscip. Hist."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"2225071","DOI":"10.1080\/17445647.2023.2225071","article-title":"Deep learning ancient map segmentation to assess historical landscape changes","volume":"19","author":"Martinez","year":"2023","journal-title":"J. Maps"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Dias, L.T., and Alarc\u00e3o, P. (2018). Construir, Navegar, (Re)Usar o Douro da Antiguidade, CITCEM.","DOI":"10.21747\/978-989-8351-95-1\/cons"},{"key":"ref_49","first-page":"77","article-title":"Cora\u00e7\u00f5es aflitos: Navega\u00e7\u00e3o e travessia do Douro na Idade M\u00e9dia e no in\u00edcio da Idade Moderna","volume":"2","author":"Duarte","year":"1997","journal-title":"Douro Estud. Doc."},{"key":"ref_50","unstructured":"Jesus, M.E.R.V.D. (2003). Morfodin\u00e2mica do Cabedelo da Foz do Rio Douro: Perspectiva Hist\u00f3rica e Monitoriza\u00e7\u00e3o por GPS para o Conhecimento da sua Evolu\u00e7\u00e3o Actual: Aplicabilidade Pedag\u00f3gica Numa Vertente CTSA. [Master\u2019s Thesis, Universidade do Porto]."},{"key":"ref_51","unstructured":"Salazar, J.M. (2025, September 08). Mapa da Barra do Douro e Parte do Rio Douro [Desenhos Aguarelados]. Cole\u00e7\u00e3o da Sociedade de Geografia de Lisboa. Reprodu\u00e7\u00e3o Digital no Arquivo Municipal do Porto. Available online: https:\/\/gisaweb.cm-porto.pt\/units-of-description\/documents\/335570\/."},{"key":"ref_52","unstructured":"Maldonado, T.d.S., and Godinho, M.d.S. (2025, October 14). Planta Geogr\u00e1fica da Barra da Cidade do Porto [Engraving]. Porto Municipal Archive, PT-CMP-AM\/COL\/GRA\/D.ALB.GRA.1-4. Available online: https:\/\/gisaweb.cm-porto.pt\/units-of-description\/documents\/428344\/."},{"key":"ref_53","unstructured":"Folque, F.d.S., Batalha, C.M., Vasconcellos, D.C.B., Albuquerque, J.E.d.A., Ferreira, A.G.T., and Guerreiro, C.A. (2025, October 14). e Plano Hydrographico da Barra do Porto [Cartographic Material]. Direc\u00e7\u00e3o Geral dos Trabalhos Geod\u00e9sicos do Reino, Available online: https:\/\/purl.pt\/22845."},{"key":"ref_54","unstructured":"Arquivo Hist\u00f3rico Municipal do Porto, and Real, M. (1992). Uma Cartografia Exemplar: Exposi\u00e7\u00e3o Comemorativa do 1.\u00ba Centen\u00e1rio da Carta Topogr\u00e1fica de A. G. Teles Ferreira, C\u00e2mara Municipal do Porto. (Coordinators)."},{"key":"ref_55","first-page":"37","article-title":"Algumas notas sobre as Invas\u00f5es Francesas em Portugal na historiografia do s\u00e9culo XIX","volume":"10","author":"Marques","year":"2009","journal-title":"Hist\u00f3ria: Rev. Fac. Let. Univ. Porto"},{"key":"ref_56","unstructured":"Couceiro, P. (2013, January 4\u20135). Peninsular war and society: The impacts of the French invasions at Porto (1807-11). Proceedings of the War, Society, and Culture in Britain, c. 1688-1830 Conference: New perspectives, List of Speakers and Abstracts, Leeds, UK."},{"key":"ref_57","unstructured":"Coelho, S.V., and Queir\u00f3s, C.S. (2020). O liberalismo entre dois lados do Atl\u00e2ntico 1820-1834. Turismo e Hist\u00f3ria\u2013Perspectivas Sobre o Patrim\u00f4nio da Humanidade no Espa\u00e7o Ibero-Americano, Educs."},{"key":"ref_58","unstructured":"(2025, September 05). Cole\u00e7\u00e3o de Plantas e Perfis das Fortifica\u00e7\u00f5es, Referidas \u00e0 Carta Geral das Linhas dos Ex\u00e9rcitos Libertador e Rebelde, No S\u00edtio do Porto [Lithographic Album]. Porto Municipal Archive, PT-CMP-AM\/COL\/GRA\/0001. Available online: https:\/\/gisaweb.cm-porto.pt\/units-of-description\/documents\/371658\/."},{"key":"ref_59","unstructured":"Telles Ferreira, A.G. (2025, September 05). Carta Topogr\u00e1fica da Cidade do Porto (Six Map Sheets, Scale 1:5000) [Cartographic Material]. Porto Municipal Archive, PT-CMP-AM\/PUB\/CMPRT\/DSCC-DAH\/1687\/F.P:CMP:12:81.1.a.6. Available online: https:\/\/gisaweb.cm-porto.pt\/units-of-description\/documents\/828837\/."},{"key":"ref_60","unstructured":"Portuguese Hydrographic Institute (2025, March 03). Wreck Point [Data Set]. Portuguese Navy. Available online: https:\/\/api-features.hidrografico.pt\/collections\/wreck_point."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1007\/s41636-020-00258-0","article-title":"\u201cMissing Cemeteries\u201d and Structural Racism: Historical Maps and Endangered African\/African American and Hispanic Mortuary Customs in Texas","volume":"54","author":"Lemke","year":"2020","journal-title":"Hist. 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