**Regarding `trainingData.xlsx`**
This text describes the model training data set, attached as a Microsoft Excel file trainingData.xlsx
The data are comprised of distinct parts, from distinct sources, as follows:
**Soil physico-chemical properties**
These data were extracted from the Victorian Soil Information System database ([VSIS][1], see Hunter et al. 2010). The original soil pit observations were the work of numerous unidentified employees of the State of Victoria, Australia.
The data custodian is Agriculture Research Victoria, part of the Victorian Department of Economic Development, Jobs, Transport and Resources.
We made minor modifications to the original soil pit dataset, combining observations within the surface (A) and subsoil (B) soil Horizons, and we present the arithmetic mean for A and B horizons respectively.
The geographic coordinates are projected in [VicGrid94][2] format.
The laboratory methods applicable to the soil properties are included in the Metadata tab of the attached file.
**Airborne radiometric data**
Estimated mean ground-level abundance of Potassium (`K_percent`) and Thorium (`Th_ppm`) extracted from the [Radiometric map of Australia][3] in November 2014. Potassium is expressed as a percentage and Thorium as parts per million (see Minty et al. 2009).
**Environmental data**
These mean annual data for solar radiation (`annRad`), temperature (`annTemp`) and precipitation (`annPrecip`) were derived from maps computed from a 50 m Digital Elevation Model (DEM) using the software package ANUCLIM 5.1 (Houlder, Hutchinson, Nix & McMahon 2000).
Relative topographic position (represented as `topographicWetnessIndex`) was computed using the Shuttle Radar Topography Mission (SRTM) 100 m Digital Elevation Model and TOPOCROP Version 1.2 (Schmidt 2002) with an extension for Arcview 3.2 that implements various Terrain Indices
**Cited literature**
Houlder, D. J., Hutchinson, M. F., Nix, H. A., & McMahon J. P. (2000). ANUCLIM User Guide, Version 5.1. Canberra.
Hunter, D., Williams, S., & Robinson, N. (2010). VSIS a new system for Victorian soil data. Proceedings of the 19th World Congress of Soil Science, Soil Solutions for a Changing World, 1–6 August, 2010, Brisbane.
Minty, B., Franklin, R., Milligan, P., Richardson, L. M., & Wilford, J. R. (2009). Radiometric Map of Australia. Exploration Geophysics, 40, 325–333.
Schmidt, F. (2002). TOPOCROP Version 1.2. Institute for Geodesy and Geoinformatics, University of Rostock, Germany.
[1]: http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/lwm_usfs_VSIS
[2]: http://api.maps.vic.gov.au/images/documents/PDF/VICGRID94MapProjectionInformation.pdf
[3]: http://www.ga.gov.au/metadata-gateway/metadata/record/gcat_70791
