par C. DEMETRESCU and M. ANGHEL
Some aspects of the calculation of the normal field by the least square method
applied to data obtained in magnetic surveys are discussed. Two problems are
studied i) the influence of an anomaly at the reference point, introduced in
the calculation by the values measured at that point, on the derived normal
field, and ii) the contribution of the normal field terms corresponding to
the coefficients having very small values and greater rms errors than the coefficients
themselves. The results lead to the following conclusions: a) the utilization
of the measured values at the reference point must be avoided; the coefficient
representing the normal field at the reference point is to be derived in the
same manner as the other coefficients of the Taylor sum; b) it is preferable
that the reference point be located as central as possible in the studied area,
in order to take advantage of certain simplifications of the normal field formula
in its practical utilization.