Aeromagnetic data processing using MATLAB

Abstract

This study focuses on the evaluation of magnetic field variation in a two-dimensional plot in form of a contour map by carrying out interpolation on the magnetic field data and mapping regional structures to infer the direction of dykes. To pinpoint areas of magnetic highs and lows, MATLAB program was used to delineate magnetic field trends on the data. The program was also used to produce graphical, colourized and contoured plots of data from XYZ files (data with random locations) using interpolation functions. The program was used for both gridding and smoothening of the magnetic field data and also allow the setting of contour values and utilization of vivid colour scales. The aeromagnetic data vector may contain outliers which are due to instrumental error and data extraction during field data collection. These outliers were removed and replaced using three interpolation methods including linear, nearest-neighbour and cubic spline to have a non-distorted representation plot and they were also used to fit surfaces to the gridded data. The result shows that the piecewise cubic spline interpolant contour plot has finer precision with higher details at the output edges. From the piecewise linear surface B(X,Y), where X is normalized by mean 2.235e+05 and standard deviation of 3.202e+04 and Y is normalized by mean 7.809e+05 and standard deviation of 551. The residual magnetic intensity plot shows the magnetic field range between -200 nT for magnetic low and 200 nT for magnetic high. However, the use of MATLAB is not to displace Oasis Montaj geosoftware but to give more scientific meaning to the automation of the filtering techniques used in Oasis.