%==================================================================================== % USER MANUAL -- TGF software %==================================================================================== % % Version 2019-10-29 % % Citation for this work: % M. Yang, C. Hirt, R. Pail (2019) TGF: A New MATLAB-based Software for Terrain % Gravity Field Calculation. Comput. Geosci., under review. %----------------------------------------------------------------------------------- % This is the user manual for TGF software which is developed for the calculations % of full-scale topographic and RTM gravitational field in the Matlab environment. % % Please consult the Quick-start file for further information, including test data % sets and simple examples for using the TGF software with its GUI or in batch mode. % % The full-scale topographic gravitational field calculated via the TGF software % is generated by the topographic masses boundied by the mean sea level and the % Earth surface, while the high-frequency RTM gravity field is caused by the % attraction of residual masses between the Earth's surafce and a reference % surface. % % In the TGF software, the topographic masses around the calculation point are % divided into four zones for RTM gravity field calculation and five zones for % full-scale topographic gravity field. The mass elements of nearest zones around % calculation points are approximated by polyhedron and prism for precise % computation, while tesseroid and point-mass for efficient computation for the % far-zone masses. Please refer to following papers for detailed information about % combination of various mass elements, and numerical evaluation of gravity field % generated by polyhedron, tesseroid, and point mass: % D. Tsoulis (2012) Analytical computation of the full gravity tensor of a % homogeneous arbitrarily shaped polyhedral source using line integral. % Geophysics 77(2), F1-F11. % D. Nagy, G. Papp, J. Benedek (2000) The gravitational potential and its % derivatives for prism. Journal of Geodesy 74, 552-560. % D. Nagy, G. Papp, J. Benedek (2002) Corrections to "The gravitational potential % and its derivatives for prism". Journal of Geodesy 76, 475-475. % T. Grombein, K. Seitz, B. Heck (2013) Optimized formulas for the gravitational % field of a tesseroid. Journal of Geodesy 87(7), 645-660. % X.L. Deng, T. Grombein, W.B. Shen, B. Heck, K. Seitz (2016) Corrections to % “A comparison of the tesseroid, prism and point-mass approaches for mass % reductions in gravity field modelling” (Heck and Seitz, 2007) and “Optimized % formulas for the gravitational field of a tesseroid” (Grombein et al., 2013). % Journal of Geodesy 90, 585-587. % M. Yang, C. Hirt, R. Tenzer, R. Pail (2018) Experiences with the use of % mass-density maps in residual gravity forward modelling. Stud. Geophys. Geod., 62. % M. Yang, C. Hirt, M. Rexer, R. Pail, D. Yamazaki (2019) The tree canopy effect % in gravity forward modelling. Geophys. J. Int., 219 (1), % https://doi.org/10.1093/gji/ggz264 . % M. Yang, C. Hirt, R. Pail (2019) TGF: A New MATLAB-based Software for Terrain % Gravity Field Calculation. Comput. Geosci., under review. %% ----------------- Structures of the TGF software -------------------------------- % The TGF software works in two modes: in interactive mode with GUI interface and % in batch mode without the GUI interface. In interative mode, the TGF interface is % divided into four functional components: Computation Point, Forward Masses, % Gravitational Field and Output: % The 'Computation Point' component specifies and located the file contains % computation point information. % The ’Forward Mass’ module defines the input file to define the topographic masses, % via the geometric upper and lower boundaries and density values. % Parameters required for gravitational field calculation are defined in the module % ‘Gravitational Field’. % The outputs are defined in the 'Output' panel. %% ---------------------- Input parameters ----------------------------------------- % ComPoints --- in binary format, list of number of points and triplet of the & spherical/ellipsoidal coordinates (lat[-90, 90], % lon [-180, 180], height [in meters]) % DetailedDEM --- Detailed DEM, in binary format % --- [minlat maxlat reslat minlon maxlon reslon elevation] % DetailedREF --- RTM reference surface with same resolution as DetailedDEM.bin % MassDensity --- Map of mass density values, same resolution as DetailedDEM.bin % --- (from nearest neigb.) % --- Only used when not a constant value is selected % --- Unit g/cm^3 % TessDEM --- DEM for tessroid zone % TessREF --- REF for tessroid zone % TessDensity --- mass density model for tessroid zone % CoarseDEM --- lower resolution DEM for far-zone % CoarseREF --- lower resolution REF for far-zone % CoarseDensity --- lower resolution mass density model for far-zone % GlobalDEM --- Global DEM for full-scale topographic gravity field calculations % GlobalREF --- Global reference DEM for full-scale topographic gravity field % calculations (mean sea level) In full-scale topographic gravity field calculations, % & constant density assumption is made in TGF software for GlobalDEM covred area. % idensity --- flag for mass density with values of 0, 1 % --- 0, constant value is used % --- 1, density map is used % ikind --- flag for the type of modelling with values of 1, 2 % --- 1, Topographic gravitational field % --- 2, RTM gravitational field % itype --- Specification of field functionals with values of 0, 1, 2, 4, 10, 103, 104 % --- 0, height anomaly / geoid height (N) in cm % --- 1, Dovs (arc-sec) and gravity disturbances (mGal) % --- 4, Dovs (arc-sec) and gravity anomaly (mGal) % --- 2, all gradients (6 elements) in E % --- 10, all functionals (geoid, Dovs, gravity disturbances, gradient tensor) % --- 103, geoid height, Dovs and gravity disturbances % --- 104, geoid height, Dovs and gravity anomaly % rzones --- integral radius specifying the computation zones rzones = [r1 r2 r3 r4] % --- r1, radius for polyhedron (detailed DEM) % --- r2, radius for prism (detailed DEM) % --- r3, radius for tesseroid (Tesseroid DEM) % --- r4, radius for point-mass (coarse DEM) % flag_earth --- flag of earth approximation with values of 0, 1 % --- 0, spherical approximation % --- 1, ellipsoidal approximation % e --- mass density in g/cm^3 when constant density assumption is used %% ------------------------ Output parameters -------------------------------------- % height anomaly in unit of centi-meter, Dov in unit of arc-sec, dg in unit of % mGal, gradients in unit of E %% ------------------------ Run TGF in batch mode ---------------------------------- % TC_GUI (vstpar,ComPoints, DetailedDEM, DetailedREF, MassDensity, TessDEM, TessREF, ... % TessDensity, CoarseDEM, CoarseREF, CoarseDensity,GlobalDEM,GlobalREF, outname, ... % ikind, itype,idensity, flag_earth,rzones, e); %% ---------------------- Notes on data formats ------------------------------------ % The input files (DEM grids) must be in binary format. You can generate your own % DEM input data in binary format using the Matlab-script Write_DEM.m. Please % consult this file for the file structure. %% ---------------------- Assistance needed ? -------------------------------------- % Write an e-mail to Meng Yang via meng.yang@tum.de or meng.yang@vip.126.com. %% -------------------------------- DISCLAIMER ------------------------------------ % The TGF is research-only software. Neither TU Munich nor any of its staff accept % any liability in connection with the use of the software, data and models provided % here. Neither TU Munich nor any of its staff make any warranty of correctness, % fitness, completeness, usefulness and accuracy of the the software, data and % models for any intented or unintended purpose. %-----------------------------------------------------------------------------------