Object-Oriented Code to Lookup Soil Texture Classes for Any Soil Classification Scheme

Abstract

TALCPP is an object-oriented C++ code to lookup soil texture classes based on any soil classification scheme. TALCPP describes each soil texture class in a given scheme as a polygon located in a biaxial (x, y) or (%sand, %clay) coordinate system. The principle to determine the texture class is to determine if, in the texture chart, the point of intersection between any two primary particles lies within a texture class polygon. The polygon inside test method is used to test if a point lies inside or outside a polygon. TALCPP also supports Range Lookup, which is the lookup of the range of soil texture classes based on a given range of particle size distributions. The texture class is determined by testing if the source polygon enclosing the given range of particle size distributions could clip the target polygon of a particular texture class. A successful clipping between these two polygons indicates that the target texture class belongs within the given range of particle size distributions. The polygon clipping method used is the algorithm adapted from Vatti's algorithm. Lastly, a graphical user interface program called TAL for Windows was also developed. This program uses TALCPP to determine soil texture classes, and is intended for everyone including non-programmers.

Acknowledgments

Dr. Detlef Deumlich (Centre for Agricultural Landscape and Land Use Research, Germany) and Mr. Simon Six (Catholic University of Leuven, Belgium) have contributed some scheme definition files.