Historical Geomagnetic Declination in Mainland Spain Derived from Topographic Fieldwork Records (1871 1940)

[EN] In 1870, the newly created Instituto Geogr & aacute;fico of Spain, the precursor of the current Instituto Geogr & aacute;fico Nacional (IGN), began to carry out work for the preparation of the National Topographic Map of Spain, a major project that would take almost 100 years to...

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Detalles Bibliográficos
Autores: Tordesillas, Jose Manuel, Pavón-Carrasco, Francisco Javier, Nuñez, Alberto, López-Muga, Marina, Camacho, Elena, Anquela Julián, Ana Belén|||0000-0001-6024-3790
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universitat Politècnica de València (UPV)
Repositorio:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglés
OAI Identifier:oai:dnet:riunet______::26244bf937c96a2cff5c3701b58041da
Acceso en línea:https://riunet.upv.es/handle/10251/234666
Access Level:acceso abierto
Palabra clave:Geomagnetism
Declination
Topographic compass
Boundary lines
National topographic map
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Descripción
Sumario:[EN] In 1870, the newly created Instituto Geogr & aacute;fico of Spain, the precursor of the current Instituto Geogr & aacute;fico Nacional (IGN), began to carry out work for the preparation of the National Topographic Map of Spain, a major project that would take almost 100 years to be completed. This work began with the measurement of geodetic bases throughout the national territory. Subsequently, the necessary topographic surveys were conducted to delimit the boundaries of municipalities, and to represent all the planimetric elements. As a part of this, surveys were carried out with topographic compasses, which allowed work to be performed at a good pace and with sufficient accuracy for cartographic purposes. The current IGN keeps in its archives all the documentation generated in the work related to the completion of this major project. The objective of this study is to extract information from this documentation on the magnetic declination measured at that time, and to evaluate it as a possible source of historic geomagnetic information for use in future works. To achieve this, we compared the recovered declination dataset with those generated for the same locations and dates using two independent sources: the Cov-Obs.x2 geomagnetic field model, which spans the last two centuries, and the declination data used to produce the first Spanish declination chart developed by the IGN at the beginning of the 20th century. The results show a clear agreement between the recovered dataset and both sources of independent declination data, suggesting that this dataset is valuable for improving our understanding of the recent geomagnetic field history and for refining main field models for the last centuries.