Implementation of the inverse distance weighting technique for airborne radiometric data

In airborne surveys the actual flight line seldom coincides with the desired, regularly spaced lines. This is due to navigational problems. Consequently, an interpolation technique has to be selected for the estimation of values at specified nodal points using values measured at neighbouring control points. Of the several techniques available, an inverse distance weighting technique (IDW) is applied to the airborne radiometric data. The validity of this technique is discussed in this paper. For comparison, a linear interpolation technique for logical justification is dealt with in detail. A situation may arise when the actual flight is remote from the desired line. In such cases an average positional estimate of the actual flight line is used for contouring purposes. The system of these flight lines in such a situation becomes irregularly spaced. A method for contouring this data is discussed in detail with specific reference to IDW. (author)