Welcome to The Soil Texture Wizard project!

In short

• A detailed project description can be found on the project's administrator website (page that should be move here).
• Download & install the soiltexture package from CRAN (see instructions here).
  
• Read the package vignette (comprehensive tutorial).
• Ask questions on the package's forum page.
• If you are an R develloper, you may:
  
• Have a look at the project summary page on r-forge.
• Download the latest package binaries to install the package on Windows, Linux or MacOS.
• Inspect the package source are available on the project SCM page.
• Check the logfile of changes made to the package.

Related projects

• aqp. 'Algorithms for Quantitative Pedology';
  
• soilwater. Provides soil water retention functions and soil hydraulic conductivity functions and pedotransfer functions to estimate their parameter from easily available soil properties;

• soil.spec. Soil spectral data exploration and regression functions;
• HydroMe. Estimation of Soil Hydraulic Parameters from Experimental Data;
• SoPhy. A defunct package that implemented a 2D water infiltration model into R;

Package installation

Features list

"The Soil Texture Wizard" is an integrated set of functions for the R software for statistical computing, that allows to:

• Create clear, readable soil texture triangles graphics (also called ternary plots or soil texture diagrams), with proper axis labels, either "neutral", or with one of the 14 soil texture classification systems actually pre-defined:

• USDA;
  
• FAO (which is also the triangle for the soil map of Europe);
  
• Aisne (France);
  
• GEPPA (France);
  
• German triangle (Bodenkundliche Kartieranleitung 1994);
  
• German triangle (Standortserkundungsanweisung SEA 1974) for forest soils (new 2011/10/11);
• German triangle (TGL 24300-05, landwirtschaftliche Böden, 1985) for arable soils (new 2011/10/15);
• Soil Survey of England and Wales (UK);
  
• Australian triangle;
  
• Belgian triangle (new 2009/10/15);
  
• Canadian triangle (new 2010/04/16);
  
• ISSS triangle (new 2010/05/13);
  
• Romanian texture triangle (new 2010-06-09);
• Polish triangle (Systematyka gleb Polski, 1989, for non-alluvial soils -- new).

Many thanks to Wei Shangguan, from the School of geography of Beijing normal university for providing the code of ISSS the triangle, to Rosca Bogdan (from Romanian Academy, Iasi Branch, Geography team) for providing the code for the Romanian triangle, to Wiktor Zelazny for providing the code for the Polish triangle (and the polish language translation of triangle labels) and to Rainer Petzold (Staatsbetrieb Sachsenforst) for providing the code of the German SEA 1974 and TGL 1985 triangles.

• Implement new texture triangles or create personalized texture triangles, that will be usable as any of the above mentioned soil textures triangle (graphs, classification, etc.);

• Numerous graphical possibilities to display soil texture data in a texture triangle, following an option system similar to R plot(), points() and text() functions:

• Simple graphics (points);
• Bubble charts (points sizes and colors are proportional to a 4th variable);
• Graph with text instead of points.

• Calculate the texture class(es) (= classification) to which belong soil texture data, in 1 of the 7 predefined system / classification / triangle (or your own custom triangle);

• Transform soil textures data from 1 particle sizes system (limits between the clay, silt and sand particles) to another particle size system, with a log-linear transformation (estimation). For instance, it is possible to convert a textures data table measured in a system that have a silt / sand limit is 60 micrometers into a system that has a silt / sand limit is 50 micrometers. It is also possible to define your own texture transformation function, and use it for on-the-fly transformation of data in texture plots or for texture classification.;

• Display a texture triangle / classification in a (triangle) geometry different from its default (triangle) geometry. For instance, a texture triangle / classification usually displayed in an isosceles triangle can be displayed in a right-angled triangle. The geometrical parameters that can be changed are:

• The 3 angles of the triangle (free);
• The "direction" of increasing textures for each axes (clockwise, anti-clockwise or "centripetal");
• The location of the 3 texture classes (clay, silt and sand) on the 3 axes (abscissae, left or right axis).

Over-plot / superimpose 2 different texture triangles / classifications into one single plot, whatever their initial "geometry" (for instance the German right-angled soil texture triangle and the USDA isosceles texture triangle can be over-plotted (into a given geometry));

• On the fly transformation of textures data particle size when plotting a soil texture triangle;

• On the fly transformation of a triangle particle size when over-plotting 2 (different) texture triangles;

• Contour plot or image plot of:

• 2D kernel density estimation (based on R-MASS kde2d function) (new 2009/10/13)
  
• Mahalanobis distance (based on R mahalanobis function), with or without additive log-ratio transformation (new 2009/10/13)
  
• Inverse weighted distance estimate / smoothing of a 4th variable;

• Normalisation of texture datas sum of the 3 texture classes to 100% (new 2009/10/13).

• Chose between 7 languages for the plot title and the 3 axes legends (English, French, Swedish, German, Spanish, Italian and Dutch), with a simple option;

• Most of the functions are optimised for speed, and are thus suitable for mass / batch treatment of soil textures data:

• 3400 soil textures data transformed per second;
  
• 14000 soil textures data "classified" per second;

Other works and softwares on soil textures (triangles)

Numerous other works and softwares exist that deal with soil textures and soil textures triangles. Nevertheless, to my knowledge, The Soil Texture Wizard is the only tool that offers an integrated set of functionalities for soil textures (smart graphs + classification + multi-triangle + multi-geometry).

Ternary graphs (without soil textures classes):

Ternary graphs (with soil textures classes):

Automatic classification:

Texture Autolookup, by Christopher Teh Boon Sung is a standalone program, with a graphical user interface, that can classify soil textures following the USDA, UK, Canadian, FAO texture triangles, or 7 other systems. The work has been published in two articles of "Communications in Soil and Plant Analysis", in 1996 and 2003. The software also allows to plot / visualise soil texture data (but the plot function is not very advanced), in 2 different triangle geometries.

r.soils.texture is a [Grass-GIS http://grass.osgeo.org/] add-on for classifying raster files of soil textures with 3 classification systems (USDA, FAO, ISSS). Note that this is not R code.

Articles related to soil texture triangles or systems

Richer de Forges A., Feller C., Jamagne M. & Arrouays D., 2008. "Perdus dans le triangle des textures" (Études et Gestion des Sols, 15:2, pp. 97-111) (en: "Lost in the textures triangle") are presenting a gallery of 29 soil textures triangles, either still in use nowadays or that were used in the past, from France and other countries, and comparing the location of soil texture triangles limits between several triangles. The article also presents a table comparing the particle size limits (for clay, silt and sand fractions) between numerous countries. See also their poster in English. The "comparison" work has been done with a geographic information system (ArcGIS?).

A. Nemes, J.H.M. Wösten, A. Lilly, and J.H. Oude Voshaar. Evaluation of different procedures to interpolate particle-size distributions to achieve compatibility within soil databases. Geoderma, 90:187-202, 1999. LINK.

Roadmap

• The functions provided by the soiltexture package are considered as beta / almost stable, but they need to be tested by more users.
• The main function TT.plot() is now documented.
• TT.points.in.classes() is also documented.
  
• The documentation is under construction for the rest of the package (using inlinedocs), and will be gradually completed.
• ...

Feedbacks, contact, license, credit and (absence of) guaranty

Feedbacks & contacts

• On the package forum page.
• Write an e-mail to the author:  jules_m78-soiltexture {AT} yahoo {DOT} fr
• Visit the author's webpage.
  

Credits

License & garantees