Digital soil mapping: A brief history and some lessons Budiman Minasny ⁎, Alex.B. McBratney Faculty of Agriculture & Environment, The University of Sydney, NSW 2006, Australia abstract article info Article history: Received 6 March 2015 Received in revised form 14 July 2015 Accepted 26 July 2015 Available online xxxx Keywords: Soil survey Pedology GlobalSoilMap Soil history Case-based reasoning Digital soil mapping (DSM) is a successful sub discipline of soil science with an active research output. The success of digital soil mapping is a confluence of several factors in the beginning of 2000 including the increased availability of spatial data (digital elevation model, satellite imagery), the availability of computing power for processing data, the development of data-mining tools and GIS, and numerous applications beyond geostatistics. In addition, there was an increased global demand for spatial data including uncertainty assessments, and a rejuvenation of many soil survey and university centres which helped in the spreading of digital soil mapping technologies and knowledge. The theoretical framework for digital soil mapping was formalised in a 2003 paper in Geoderma. In this paper, we define what constitutes digital soil mapping, sketch a brief history of it, and discuss some lessons. Digital soil mapping requires three components: the input in the form of field and laboratory observational methods, the process used in terms of spatial and non-spatial soil inference systems, and the output in the form of spatial soil information systems, which includes outputs in the form of rasters of prediction along with the uncertainty of prediction. We also illustrate the history with a number of sleeping beauty papers that seem too precocious and consequently the ideas were not taken up by contemporaries and largely forgotten. It took another 30 to 40 years before the ideas were rediscovered and then flourished. Examples include proximal soil sensing that was developed in the 1920s, soil spectroscopy in 1970s, and soil mapping based on similarity of environmental factors in 1979. In summary, the coming together of emerging topics and timeliness greatly assists in the development of paradigm. We learned that research and ideas that are too precocious are largely ignored — such work warrants (re)discovery. © 2015 Published by Elsevier B.V. 1. Introduction Digital soil mapping (DSM) has become a successful sub-discipline of soil science. Currently, the number of papers on DSM increases at a rate of 12 papers per year, and the number of citations increases by 384 citations per year (Fig. 1). The use of computer or numerical models to map soil is not new and researches into methods for creating digital soil maps have been produced since the 1990s (e.g. Skidmore et al., 1991; Bell et al., 1992; Odeh et al., 1992a; McKenzie and Austin, 1993; Moore et al., 1993). McBratney et al. (2003) noted their commonalities and proposed a generic framework called the scorpan-SSPFe (soil spatial prediction function with spatially autocorrelated errors) as a method to produce digital soil maps. The term digital soil maps has been used since early on, for example Roger Tomlinson, the father of GIS (Tomlinson, 1978) labelled digitised polygon maps as digital soil maps. Similarly, Bliss and Reybold (1989) and Bliss et al. (1995) converted the STATSGO polygon maps into “digital soil maps”. Dobos et al. (2002) used the term “digital soil mapping” as a way of integrating soil maps with DEM and satellite sensing images. The aim of this paper is to define what constitutes digital soil map- ping following the framework of scorpan-SSPFe and reviews several re- search topics that contribute to the development of digital soil mapping. We will sketch a brief history using examples from several pioneering soil mapping studies, highlighting some ‘sleeping beauties’ papers and their rediscovery, and then discuss some lessons for the future. Since the digital soil mapping scorpan concept was introduced, and following a series of global workshops, there has been huge interest in this topic of research. The first global digital soil mapping workshop was held in Montpellier in September 2004. The IUSS working group on Digital Soil Mapping was formed following the first workshop. Successive global workshops were held in Rio De Janeiro, Brazil in 2006, Logan, USA in 2008, Rome, Italy in 2010, Sydney, Australia in 2012 and in Nanjing, China in 2014. It has resulted in a series of books (Lagacherie et al., 2006; Hartemink et al., 2008; Boettinger, 2010; Minasny et al., 2012). Following the second global workshop in 2006, the GlobalSoilMap project was initiated (Arrouays et al., 2014; Hempel et al., 2014). This paper does not attempt to give a history of soil mapping, which has been covered in many reviews (Yaalon, 1989; Brown, 2006; Legros, 2006; Hartemink et al., 2013; Miller and Schaetzl, 2014). It also will not discuss the history of pedometrics research (Webster, 1994). Bui (2006) provided a review of digital soil mapping development in Australia until Geoderma xxx (2015) xxx–xxx ⁎ Corresponding author. E-mail address: Budiman.minasny@sydney.edu.au (B. Minasny). GEODER-12047; No of Pages 11 http://dx.doi.org/10.1016/j.geoderma.2015.07.017 0016-7061/© 2015 Published by Elsevier B.V. Contents lists available at ScienceDirect Geoderma journal homepage: www.elsevier.com/locate/geoderma Please cite this article as: Minasny, B., McBratney, A.B., Digital soil mapping: A brief history and some lessons, Geoderma (2015), http://dx.doi.org/ 10.1016/j.geoderma.2015.07.017