{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T08:27:59Z","timestamp":1773736079013,"version":"3.50.1"},"reference-count":47,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2016,12,14]],"date-time":"2016-12-14T00:00:00Z","timestamp":1481673600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Increasingly, electromagnetic induction methods (EMI) are being used within the area of archaeological prospecting for mapping soil structures or for studying paleo-landscapes. Recent hardware developments have made fast data acquisition, combined with precise positioning, possible, thus providing interesting possibilities for archaeological prospecting. However, it is commonly assumed that the instrument operates in what is referred to as Low Induction Number, or LIN. Here, we detail the problems of the approximations while discussing a best practice for EMI measurements, data processing, and inversion for understanding a paleo-landscape at an Iron Age human bone depositional site (Alken Enge) in Denmark. On synthetic as well as field data we show that soil mapping based on EMI instruments can be improved by applying data processing methodologies from adjacent scientific fields. Data from a 10 hectare study site was collected with a line spacing of 1\u20134 m, resulting in roughly 13,000 processed soundings, which were inverted with a full non-linear algorithm. The models had higher dynamic range in the retrieved resistivity values, as well as sharper contrasts between structural elements than we could obtain by looking at data alone. We show that the pre-excavation EMI mapping facilitated an archaeological prospecting where traditional trenching could be replaced by a few test pits at selected sites, hereby increasing the chance of finding human bones. In a general context we show that (1) dedicated processing of EMI data is necessary to remove coupling from anthropogenic structures (fences, phone cables, paved roads, etc.), and (2) that carrying out a dedicated full non-linear inversion with spatial coherency constraints improves the accuracy of resistivities and structures over using the data as they are or using the Low Induction Number (LIN) approximation.<\/jats:p>","DOI":"10.3390\/rs8121022","type":"journal-article","created":{"date-parts":[[2016,12,14]],"date-time":"2016-12-14T10:14:47Z","timestamp":1481710487000},"page":"1022","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":54,"title":["Improved Geoarchaeological Mapping with Electromagnetic Induction Instruments from Dedicated Processing and Inversion"],"prefix":"10.3390","volume":"8","author":[{"given":"Anders","family":"Christiansen","sequence":"first","affiliation":[{"name":"Department of Geoscience, Aarhus University, H\u00f8egh-Guldbergs Gade 2, 8000 Aarhus C, Denmark"}]},{"given":"Jesper","family":"Pedersen","sequence":"additional","affiliation":[{"name":"Department of Geoscience, Aarhus University, H\u00f8egh-Guldbergs Gade 2, 8000 Aarhus C, Denmark"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5397-4832","authenticated-orcid":false,"given":"Esben","family":"Auken","sequence":"additional","affiliation":[{"name":"Department of Geoscience, Aarhus University, H\u00f8egh-Guldbergs Gade 2, 8000 Aarhus C, Denmark"}]},{"given":"Niels","family":"S\u00f8e","sequence":"additional","affiliation":[{"name":"Department of Geoscience, Aarhus University, H\u00f8egh-Guldbergs Gade 2, 8000 Aarhus C, Denmark"}]},{"given":"Mads","family":"Holst","sequence":"additional","affiliation":[{"name":"Section for Archaeology, Department of Culture and Society, Aarhus University\/Moesgaard Museum, Moesg\u00e5rd Alle 15, DK-8270 H\u00f8jbjerg, Denmark"}]},{"given":"S\u00f8ren","family":"Kristiansen","sequence":"additional","affiliation":[{"name":"Department of Geoscience, Aarhus University, H\u00f8egh-Guldbergs Gade 2, 8000 Aarhus C, Denmark"}]}],"member":"1968","published-online":{"date-parts":[[2016,12,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1111\/j.1475-4754.2008.00388.x","article-title":"Detecting trends in the prediction of the buried past: A review of geophysical techniques in archaeology","volume":"50","author":"Gaffney","year":"2008","journal-title":"Archaeometry"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"166","DOI":"10.1111\/ejss.12177","article-title":"Combining EMI and GPR for non-invasive soil sensing at the Stonehenge World Heritage Site: The reconstruction of a WW1 practice trench","volume":"66","author":"Saey","year":"2015","journal-title":"Eur. J. Soil Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1002\/arp.313","article-title":"Recent results from the English Heritage caesium magnetometer system in comparison with recent fluxgate gradiometers","volume":"14","author":"Linford","year":"2007","journal-title":"Archaeol. Prospect."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1002\/arp.1458","article-title":"Assessment of the CMD mini-explorer, a new low-frequency multi-coil electromagnetic device, for archaeological investigations","volume":"20","author":"Bonsall","year":"2013","journal-title":"Archaeol. Prospect."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1002\/arp.303","article-title":"Mixed method approaches to the investigation and mapping of buried Quaternary deposits: Examples from southern England","volume":"14","author":"Bates","year":"2007","journal-title":"Archaeol. Prospect."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1016\/j.geoderma.2012.07.019","article-title":"Exploring the potential of multi-receiver EMI survey for geoarchaeological prospection: A 90ha dataset","volume":"199","author":"Saey","year":"2013","journal-title":"Geoderma"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1016\/j.jas.2014.06.020","article-title":"Unveiling the prehistoric landscape at Stonehenge through multi-receiver EMI","volume":"50","author":"Saey","year":"2014","journal-title":"J. Archaeol. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1007\/s11119-008-9070-4","article-title":"Bayesian analysis of within-field variability of corn yield using a spatial hierarchical model","volume":"10","author":"Jiang","year":"2009","journal-title":"Precis. Agric."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1016\/j.compag.2010.04.011","article-title":"Site-specific management units in a commercial maize plot delineated using very high resolution remote sensing and soil properties mapping","volume":"73","author":"Casterad","year":"2010","journal-title":"Comput. Electron. Agric."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"175","DOI":"10.2113\/JEEG15.3.175","article-title":"Soil conductivity and multiple linear regression for precision monitoring of beef feedlot manure and runoff","volume":"15","author":"Eigenberg","year":"2010","journal-title":"J. Environ. Eng. Geophys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1007\/s11119-012-9281-6","article-title":"Apparent electrical conductivity in dry versus wet soil conditions in a shallow soil","volume":"14","author":"Serrano","year":"2013","journal-title":"Precis. Agric."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1007\/s10712-011-9138-y","article-title":"Theoretical developments in electromagnetic induction geophysics with selected applications in the near surface","volume":"33","author":"Everett","year":"2012","journal-title":"Surv. Geophys."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.geoderma.2014.01.027","article-title":"The use of electromagnetic induction techniques in soils studies","volume":"223","author":"Doolittle","year":"2014","journal-title":"Geoderma"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"316","DOI":"10.1016\/j.jhydrol.2015.07.023","article-title":"Field test of a multi-frequency electromagnetic induction sensor for soil moisture monitoring in southern Italy test sites","volume":"529","author":"Calamita","year":"2015","journal-title":"J Hydrol."},{"key":"ref_15","unstructured":"McNeill, J.D. (1996). Why Doesn\u2019t Geonics Limited Build a Multi-Frequency EM31 or EM38?, Geonics Limited. Technical note TN-30."},{"key":"ref_16","unstructured":"McNeill, J. (1980). Electromagnetic Terrain Conductivity Measurement at Low Induction Numbers, Geonics Limited. Technical Report TN-6."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"158","DOI":"10.2136\/vzj2006.0120","article-title":"Vertical spatial sensitivity and exploration depth of low-induction-number electromagnetic-induction instruments","volume":"6","author":"Callegary","year":"2007","journal-title":"Vadose Zone J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"85","DOI":"10.2136\/sssaj2011.0003","article-title":"Three-dimensional sensitivity distribution and sample volume of low-induction-number electromagnetic-induction instruments","volume":"76","author":"Callegary","year":"2012","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"382","DOI":"10.1190\/1.1439028","article-title":"A note on the electromagnetic response of a stratified earth","volume":"27","author":"Wait","year":"1962","journal-title":"Geophysics"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1016\/j.jappgeo.2004.04.005","article-title":"1-D laterally constrained inversion of EM34 profiling data","volume":"56","author":"Santos","year":"2004","journal-title":"J. Appl. Geophys."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"De Smedt, P., Van Meirvenne, M., Herremans, D., De Reu, J., Saey, T., Meerschman, E., Cromb\u00e9, P., and De Clercq, W. (2013). The 3-D reconstruction of medieval wetland reclamation through electromagnetic induction survey. Sci. Rep., 3.","DOI":"10.1038\/srep01517"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1002\/arp.425","article-title":"Electrical conductivity depth modelling with a multireceiver EMI sensor for prospecting archaeological features","volume":"19","author":"Saey","year":"2012","journal-title":"Archaeol. Prospect."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1729","DOI":"10.2136\/sssaj2015.06.0238","article-title":"Mapping salinity in three dimensions using a DualEM-421 and electromagnetic inversion software","volume":"79","author":"Zare","year":"2015","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1319","DOI":"10.2136\/vzj2011.0035","article-title":"Quantitative two-layer conductivity inversion of multi-configuration electromagnetic induction measurements","volume":"10","author":"Mester","year":"2011","journal-title":"Vadose Zone J."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Dafflon, B., Hubbard, S.S., Ulrich, C., and Peterson, J.E. (2013). Electrical conductivity imaging of active layer and permafrost in an Arctic ecosystem, through advanced inversion of electromagnetic induction data. Vadose Zone J., 12.","DOI":"10.2136\/vzj2012.0161"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"3490","DOI":"10.1002\/2014WR016245","article-title":"Estimation of soil salinity in a drip irrigation system by using joint inversion of multicoil electromagnetic induction measurements","volume":"51","author":"Jadoon","year":"2015","journal-title":"Water Resour. Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"757","DOI":"10.2136\/vzj2005.0116","article-title":"Electrical conductivity of a failed septic system soil absorption field","volume":"5","author":"Lee","year":"2006","journal-title":"Vadose Zone J."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"382","DOI":"10.2136\/sssaj2012.0276","article-title":"Identifying soil patterns at different spatial scales with a multi-receiver emi sensor","volume":"77","author":"Saey","year":"2013","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"E103","DOI":"10.1190\/geo2014-0549.1","article-title":"Interpretation of shallow electromagnetic instruments resistivity and magnetic susceptibility measurements using rapid 1D\/3D inversion","volume":"81","author":"Benech","year":"2016","journal-title":"Geophysics"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1002\/arp.1535","article-title":"Slingram EMI devices for characterizing resistive features using apparent conductivity measurements: Check of the DualEM-421S instrument and field tests","volume":"23","author":"Dabas","year":"2016","journal-title":"Archaeol. Prospect."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"WB99","DOI":"10.1190\/geo2011-0507.1","article-title":"Modeling the electrical conductivity of hydrogeological strata using joint-inversion of loop-loop electromagnetic data","volume":"77","author":"Triantafilis","year":"2012","journal-title":"Geophysics"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"629","DOI":"10.3997\/1873-0604.2009043","article-title":"A review of helicopter-borne electromagnetic methods for groundwater exploration","volume":"7","author":"Siemon","year":"2009","journal-title":"Near Surf. Geophys."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1983","DOI":"10.1190\/1.1444882","article-title":"Advanced inversion methods for airborne electromagnetic exploration","volume":"65","author":"Sengpiel","year":"2000","journal-title":"Geophysics"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Auken, E., Viezzoli, A., and Christiansen, A.V. (2009, January 22\u201325). A single software for processing, inversion, and presentation of AEM data of different systems: The Aarhus Workbench. Proceedings of the International Geophysical Conference and Exhibition, Adelaide, SA, Australia.","DOI":"10.1071\/ASEG2009ab062"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1071\/EG08128","article-title":"An integrated processing scheme for high-resolution airborne electromagnetic surveys, the SkyTEM system","volume":"40","author":"Auken","year":"2009","journal-title":"Explor. Geophys."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Pedersen, J.B., Auken, E., Vest, C.A., and Kristiansen, S.M. (2015, January 6). Mapping soil heterogeneity using spatially constrained inversion of electromagnetic induction data. Proceedings of the First Conference on Proximal Sensing Supporting Precision Agriculture, Turin, Italy.","DOI":"10.3997\/2214-4609.201413833"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"S\u00f8e, N.E., Odgaard, B., Hertz, E., Holst, M.K., and Kristiansen, S.M. (2016). Geological setting of a sacred landscape: Iron age post battle depositions at Alken Enge, Denmark. Geoarchaeology, submitted.","DOI":"10.1002\/gea.21622"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"553","DOI":"10.3997\/1873-0604.2010037","article-title":"Electromagnetic induction calibration using apparent electrical conductivity modelling based on electrical resistivity tomography","volume":"8","author":"Rings","year":"2010","journal-title":"Near Surf. Geophys."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1071\/EG13097","article-title":"An overview of a highly versatile forward and stable inverse algorithm for airborne, ground-based and borehole electromagnetic and electric data","volume":"46","author":"Auken","year":"2015","journal-title":"Explor. Geophys."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.jappgeo.2014.12.017","article-title":"Integrated interpretation of helicopter and ground-based geophysical data recorded within the Okavango Delta, Botswana","volume":"114","author":"Podgorski","year":"2015","journal-title":"J. Appl. Geophys."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Mikucki, J.A., Auken, E., Tulaczyk, S., Virginia, R.A., Schamper, C., Sorensen, K.I., Doran, P.T., Dugan, H., and Foley, N. (2015). Deep groundwater and potential subsurface habitats beneath an Antarctic dry valley. Nat. Commun., 6.","DOI":"10.1038\/ncomms7831"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"899","DOI":"10.1016\/j.crte.2009.07.006","article-title":"An integrated study of the hydrogeology of volcanic islands using helicopter borne transient electromagnetic: Application in the Gal\u00e1pagos Archipelago","volume":"341","author":"Auken","year":"2009","journal-title":"Comptes Rendus Geosci."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"F105","DOI":"10.1190\/1.2895521","article-title":"Quasi-3d modeling of airborne tem data by spatially constrained inversion","volume":"73","author":"Viezzoli","year":"2008","journal-title":"Geophysics"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"WB171","DOI":"10.1190\/geo2011-0393.1","article-title":"A global measure for depth of investigation","volume":"77","author":"Christiansen","year":"2012","journal-title":"Geophysics"},{"key":"ref_45","unstructured":"Taylor, R. Apparent Conductivity as an Indicator of Thickness. Available online: http:\/\/www.dualem.com\/acit.htm."},{"key":"ref_46","unstructured":"S\u00f8e, N.E., Odgaard, B., Nielsen, A.B., Olsen, J., and Kristiansen, S.M. (2016). The making of a sacred landscape: Late Holocene palaeoecology of Ils\u00f8 and the Illerup\/Alken Enge valley, Denmark. Veg. Hist. Archaeobothany, submitted."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1080\/13505033.2016.1182768","article-title":"In-situ preservation solutions for deposited Iron age human bones in Alken Enge, Denmark","volume":"18","author":"Matthiesen","year":"2016","journal-title":"Conserv. Manag. Archaeol. 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