Advanced features for the optimal gridding of high gradient gravity data

Purpose. Geological organizations of Ukraine create digital data banks for surveys, including gravimetric ones. New standards for data processing involve the use of GIS and the means for creating digital maps of geophysical fields. The results of their digitization are ambiguous. The features of interpolation methods for different initial information are analyzed.

Design/Methodology/Approach. Interpolation of gravity field with different qualitative characteristics for 12 methods of gridding is made. Piecewise linear interpolation is applied. The smoothness of the curve is ensured by interpolating the nodes with arcs of circles (parabolas) and cubic curves, but the latter method is unsuitable for the exact approximation of the gradient field of gravity. Recommendations on the choice of parameters have been developed.

Findings. The choice of the optimal method of data interpolation determines the content of the digitization of isoline maps. Comparison of the results of the approximation of gravity data by different methods has shown that none of the methods approaches the exact solution. Methods are indicated that give acceptable accuracy and certain conditions for their action are given.

The complexities of preliminary processing of initial measurements, including adequate display of the observation grid, are studied, the criteria for their improvement are proved by optimizing the gridding parameters for a particular survey and use of the data controlled filtering. To obtain a meaningful solution, you need to clarify the nature of the input data, and for different physical parameters of the environment, you need to use different methods of the problem. Recommendations for the application of methods for generating digital maps of gravitational anomalies are developed.

Practical value/implications. These steps reduce by ~ 10–15% the uncertainty in solving inverse problems. To increase the contrast, linear convolution filters and non-linear filters should be used. Recommendations are applied to the technology of digitization of paper maps of isolines.