VisualAnomaly: A GIS-based multifractal method for geochemical and geophysical anomaly separation in Walsh domain

Anomaly separation plays an important role in mineral exploration and other applications. The GIS-based package presented in this study provides an anomaly separation method which accomplishes anomaly separation in Walsh domain. It is based on the Walsh transformation, which utilizes discontinuous square waveforms as its base. Hence, edge effects can be avoided and abrupt internal changes can also be preserved. The new model depends on studying and exploiting multifractal properties in Walsh domain. It overcomes the common problems of edge effects and smoothing off high-frequency signals associated with traditional methods implemented in space and Fourier domain on the basis of statistical, spatial autocorrelation, or multifractal properties. This package has been developed as independent software or a plug-in component for GIS package, such as ArcGIS and GeoDAS GIS. For validation and demonstration purposes, a case study of arsenic element concentration values was chosen for 1984 lake sediment samples from southwestern Nova Scotia, Canada. The results show good agreement between extracted anomalies and distribution of known gold mineral deposits.