1. A method of selection and positioning of a transducer in an environmental volume, comprising the steps of: a. mapping selected positions in the volume on a spherical surface, the surface having a radial center representing the position of the transducer; b. overlaying on the mapped spherical surface a mating spherical map of spatial characteristics of the transducer; whereby a distortion-free spherical-surface composite map of the transducer characteristics and volume positions is provided to enable selection and positioning of a transducer appropriate to the positions.