A modified basal outlining algorithm for identifying topographic highs from gridded elevation data, Part 1: Motivation and methods

A new approach is developed to improve the automated identification and characterization of topographic highs having quasi-elliptical basal shapes. It is designed for the study of volcanic edifices in subaerial and submarine environments, but may be applied to identify any enclosed topography feature within a digital elevation model. The procedure utilizes the results of a standard closed-contouring approach, but then adjusts the elevation of the volcanic base by evaluating the shape of the edifice along a series of topographic profiles. The algorithm overcomes the principal limitations of a stand-alone closed-contouring approach and provides improved estimates of edifice size that are less sensitive to topographic gradients and the choice of contour search interval.