01572naa a2200193 a 450000100080000000500110000800800410001910000210006024501250008126000090020652010100021565000170122565000090124265300120125165300200126370000160128370000190129977300600131810746722010-01-18       1981    bl ---       0--  u    #d1 aMCBRATNEY, A. B.  aThe design of optimal sampling schemes for local estimation and mapping of regionalized variables - I theory and method.  c1981  aSurveys of materials at the earth's surface, especially soil, can be planned to make the best use of the resources four survey or to achievea certain minimum precision provided the nature of spatial dependence is known already. A method is described for designing optimal sampling schemes. It is based on the theory of regionalized variables, and assumes that spatial dependence is expressed quantitatively in the form of the semi-variagram. It sampling scheme. By sampling on a regular triangular grid, the maximum standard error is kept to a minimum for any given sampling, but a square grid is approximately equivalent where variation is isotropic. Given the semi-variagram for a variable, the sampling density for any prescribed maximum standard error is determined. Where variation is geometrically anisotropic, the same method is employed to determine sample spacing in the direction of maximum change, and the grid mesh elongated in the perpendicular direction in proportionto the anisotropy ratio.  aLevantamento  aSolo  aAmostra  aGeoestatística1 aWEBSTER, R.1 aBURGESS, T. M.  tComputers and Geosciencesgv. 7, n. , p. 331-365, 1981.