THREE-DIMENSIONAL, CROSS-SEMIVARIOGRAM CALCULATIONS FOR HYDROGEOLOGICAL DATA |
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| Authors: | Jonathan D Lstok Richard M Cooper Alan L Flint |
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| Institution: | Assistant Professor, Department of Agricultural Engineering, Oregon State University, Corvallis, Oregon 97331.;Water Resources Engineer, Water Resources Division, South Florida Water Management District, P.O. Box V, West Palm Beach, Florida 33402.;Hydrologist, U.S. Geological Survey, Mercury, Nevada 8902 3. |
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| Abstract: | Abstract. Geostatistics is a powerful tool for the analysis of hydrogeological data, but few well-documented computer programs for performing the necessary calculations have been presented in the technical literature. This is especially true for applications that require either three-dimensional or multivariate analyses. This paper describes a FORTRAN subroutine, VARIO, that can be used to compute experimental direct- and cross-semivariograms from a set of sample data, for any specified direction in one-, two-, or three-dimensional space. The subroutine combines into groups those sample pairs that fall within predetermined angular tolerances of the specified direction. The number of sample pairs used to compute the value of the experimental semivariogram at each value of separation can be specified in four different ways, depending on the nature of the available data. Written in FORTRAN 77, VARIO can be used on any computer that supports a FORTRAN 77 compiler. Source code listing, user instructions, and example input and output data for VARIO are presented. |
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