Abstract: In this paper, we give the two improved formulas of distance, which can be used in the G-P algorithm, and the corresponding recurrence formulas, which improves the G-P algorithm,We present a rule and a mathematical model to determine no-scale interval. Such a algorithm to solve the end points of the interval can be applied to the signal processing of the seismic prospecting. The no-scale interval and the fractaldimension of time data series of the seismic tunnel are computed as well in our work.

Key words: algorithm, fractal dimension, no-scale interval, approximation