GTeC—A versatile MATLAB tool for a detailed computation of the terrain correction and Bouguer gravity anomalies.

Gravity Terrain Correction (GTeC) is a versatile MATLABcode for terrain correction aimed to this pur-pose and capable of going beyond the limits of other public domain codes targeted to this aim.It runs with input gravity data (absolute measurements or free air anomalies) at the land/sea surfaceand with one or more DTMs (indifferently gridded or scattered) at different detail levels. Each of themcan be used to calculate the gravity contribution of a concentric terrain zone around the point stationwith increasing resolution toward the center. The user can choose between two alternative algorithmsfor terrain modeling. The simplest one considers each grid point as the flat top of a squared prism. Forareas closer to the point station a second algorithm can be chosen to better approximate the relief, withrespect to others formulas, by means of a tessellation based network formed by triangular prisms. Amore precise terrain correction is therefore achieved, especially in presence of high topographic gra-dients or just outside the sea/land boundaries. In the last case a suitable algorithm was expressly devisedto fit the tessellation based network to the irregular trend of the coastline.GTeC calculates also free air anomalies and both plate and curvature corrections, providing also acomplete graphic output including topography, free air anomalies, plate correction, total terrain cor-rection, Bouguer anomalies and the terrain effect due to each computational zone.GTeC speeds up CPU times taking advantage from the parallel computing functions and from thevectorization code, both exploited in MATLABs. Two code versions of GTeC (for normal or parallelcomputation), executable under MATLAB environment (pcode), are fully available as public domainsoftware.The results of a synthetic case, of a real case at the regional scale and of a microgravity survey carriedout at a short scale, are here presented.