A first application of the multidimensional interpolation approach to a crystalline system, namely for the determination of the structural parameters of the high-pressure Cmcm phase of InAs, is reported. The method of local three-dimensional (3D) geometry investigation is based on the fitting of the experimental x-ray absorption near edge structure (XANES) data using a multidimensional interpolation of spectra as a function of structural parameters and full multiple scattering (MS) calculations. The procedure is divided into the following steps: the construction of an interpolation polynomial, the calculation of its energy-dependent coefficients using multiple scattering theory, and the minimization of the discrepancy between interpolated and experimental data varying structural parameters. Additionally, the method of XANES calculations has been tested for the reference phase of InAs (with Fm3m symmetry) with well-known structure. To achieve a higher sensitivity of the method on the structural parameters and to exclude the influence of non-structural factors on the results of the fitting, we have analysed the differences between spectra corresponding to the different crystal phases. The best-fit geometry with the cell parameters a = c = 5.366 Å and b = 5.411 Å and the internal cell parameter (which corresponds to the displacement of atoms in the y direction) δ = 0.025, has been found for InAs at 19 GPa.