02207nam a2200265 a 450000100080000000500110000800800410001902000180006010000230007824500690010126000750017030000110024549000490025650000870030552014110039265000090180365000240181265000280183665000170186465000090188165000120189065000090190265300180191165300120192912116552004-01-21       1977    bl uuuu      00u1 u    #d  a90-220-0608-51 aGRUIJTER, J. J. de  aNumerical classification of soils and its application in survey.  aWageningen: Centre for Agricultural Publishing and Documentationc1977  a117 p.  a(PUDOC. Agricultural Research Reports, 855).  aAppendix 1 (maps 1-6), appendix 2 (maps 7-12), appendix 3, appendix 4, appendix 5.  aNumerical classification of soils was studied with emphasis on methodology and feasibility in survey. A procedure was designed for construction of classes sufficiently homogeneous in terms of relevant properties and handlable by the surveyor. In the procedure 'central' depth-profiles are calculeted separately for each property (e.g. clay content), from a sample of depth-profiles, with a relocation method minimizing within-class variances. Any soil profile can thus be identified in the field by allocating its constituent depth-profiles to the central depth-profile the is most similar for the respective properties. Resulting strings of class labels serve for interim data recording. If too many combinations of central depth-profiles arise to map all individually, they are fused into larger classes and within-class variances are again minimized. This procedure was applied to survey data from a marine clay area in the Netherlands: field estimates for 6 properties in 2212 profiels divided into 20 depth intervals. A new method was used to map classes automatically. Tests showed that: samples of several hundred profiles were needed; other of profiles and initial solution for relocation had little effect on results; only extreme weighting significantly affected homogeneity for different variables. Choise of weights and number of classes should be related and supported by sensitivity analysis.  aSoil  asoil classification  aClassificação do Solo  aLevantamento  aMapa  aMétodo  aSolo  aClassificacao  aMethods