InputFileFormat

MeshTran file format description

This section contains the description of parameters that conform the MeshTran input file named set_meshtran.io.

Mesh Nature and Threads

Key	Type	Description
MESH_NATURE	character	Defines the nature/origin of the mesh to be built. Currently supported value: native.
THREADS	int	Number of threads used for the mesh generation process.

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Digital Elevation Model (DEM) Information

Input Files

Key	Type	Description
DEM_FILE	character	File name of Digital Elevation Model (DEM) in XYZ format.
DEM_LatLon	character	The DEM file is in Latitud Longitud?. If not then kilometers or meters must be indicated.
DEM_Units	character	If the DEM is not in Latitude Longitud, then specify if it is in meters or kilometers.
HAS_SEA	character	If the survey area involves sea, and therefore coast line. yes option must be indicated
ELEV_INTER	real	This option specify the elevation interpolation range. As big the number is, greater the searching ratio, slower the computation time but better the topography definition. On the other hand, as small the number is, smaller the searching ratio, faster the computation time but poorly represented the topography will be.
TOPO_FILE	character	Name of the file containing the topographic data. The file name is user-defined.
BATHY_FILE	character	Name of the file containing the bathymetry data. The file name is user-defined.
COSLI_FILE	character	Specifies the name of the file containing the coastline information. FEMTIC expects the file to be named coast_line.dat.

Analysis Domain

Key	Type	Description
XMIN_DOM	real	Defines the West boundary of the analysis domain in local coordinates, in kilometers.
XMAX_DOM	real	Defines the East boundary of the analysis domain in local coordinates, in kilometers.
YMIN_DOM	real	Defines the South boundary of the analysis domain in local coordinates, in kilometers.
YMAX_DOM	real	Defines the North boundary of the analysis domain in local coordinates, in kilometers.
ZMIN_DOM	real	Defines the Deepest boundary (the subsurface) of the analysis domain in local coordinates, in kilometers.
ZMAX_DOM	real	Defines the Highest boundary (the air layer) of the analysis domain in local coordinates, in kilometers.
PAD_X	real	Defines extra padding in x-direction beyond the analysis domain.
PAD_Y	real	Defines extra padding in y-direction beyond the analysis domain.

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Observation Data

Key	Type	Description
ERROR_TREATMENT	character	Defines the type of error to be used. The available options are floor and assigned.Each option works as follows: floor: implements an error floor for the data. If the data error is lower than the threshold defined by IN_DIAG_ERR, the error is set to IN_DIAG_ERR. Otherwise, the original data error is retained. assigned: ignores the original data error and assigns a fixed error to the in-phase and out-of-phase elements using IN_DIAG_ERR and OFF_DIAG_ERR, respectively.
IN_DIAG_ERR	int	Percentage error for IN diagonals terms.
OFF_DIAG_ERR	int	Percentage error for OFF diagonals terms.
KEYWORD_LAT	character	Defines the name of the falg in *.edi file indicating latitude, usually LAT.
KEYWORD_LONG	character	Defines the name of the flag in *.edi file indicating longitude, sometime LONG but also LON.
IMPROVE_HF	character	By the activation of this option through keyword yes the observe.dat file will include the dummy station of Vertical Transfer Function (VTF), to enhance the response at high frequencies, as it is described in the Femtic User Manual.

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Surface Mesh Configuration

Key	Type	Description
NUM_ELIPSES	int	Define the number of spheres will be used forrefinement around eachat site location.
SITEpadding	real	Define an additional zone, in kilometers, extending the fine mesh beyond the site zone.
FARelemSIZE	real	Set the element size at the model boundaries ("covers") .
SURF_RESOLUTION	real	Defines the surface resolution, i.e., the element size around the sites locations.
GROWTH	real	Defines the growth rate of element size from the center of the site location to the outer ellipses.

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Meshing over site zone

Key	Type	Description
NUM_ESFERAS	int	Define the number of spheres for refinement at each site location
ROTATION	int	Define the rotation angle, in degrees, for trend refinement.
minRADIO	real	Define the minimum radius of sphere, in kilometers, at each site location.
maxRADIO	real	Define the maximum radius of sphere, in kilometers, at each site location.
minEDGES	real	Define the minimum element edge length contained within the sphere. This value must be less than the minimum radius defined by minRADIO option.

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Volumetric Refinement

Key	Type	Description
REFI_ELLIPSES	int	Defines the number of ellipses to be considered for the refinement process.
HIGH_RESOL_LAYER	real	Defines the thickness of the high-resolution layer from the surface to the specified target depth. The thickness is calculated as the product of HRL and the target depth (TargDep).
V_PADDING	real	Vertical extension beyond the high resolution layer.
NEAR_FIELD_RESOL	int	Minimuim element size, below the surface site locations.
FAR_FIELD_RESOL	int	Set the maximum element size of volumetric mesh inside the model "covers".
ITER_TET_REFI	int	Set the number of iterations to be perfomed during the iterative refinement process.
H_PADDING	int	Define an additional zone below the surface to extend the fine volumetric mesh.
TARGET_DEPTH	int	Boundary at whitch the element size starts to increase rapidly.

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Model Region Attributes

Key	Type	Description
ELLIPSES	int	Specifies the number of ellipses used to construct the mesh parameters. As in the finite element mesh, the mesh parameters are constructed based on ellipses.
REGIONS	int	Specifies the number of regions used for the mesh parameters. For example, a land-sea model consists of three regions: air, land, and sea.
LOCATION	real	Provides the coordinates of one point within each region in XYZ format. For example, a land-only model consists of two regions, air and land, so the coordinates of both regions must be specified as X Y Z [one or more blank spaces] X Y Z.
ID_REGION	int	Specifies a simple tag used to identify each region during volumetric mesh generation and conversion from TetGen to FEMTIC mesh.
RHO_REGIONS	real	Sets the resistivity values, in Ohm-m, for each region of the mesh.
REP_PARTITION	int	For the construction of mesh parameters there is a partiton algorithm implemented here (see How_To_Make_Tetra_Mesh_For_FEMTIC manual) for lakes, sea and air -1 is the option to be choosed, Otherwise a positive number must be specified.
FIX_RESISTIVITY	int	Specifies whether the resistivity of the corresponding region is fixed. Yes -> 1, No -> 0.
PARAM_ESFER	int	Sets the number of spheres used for the mesh parameters, as in the finite element mesh.
PARAM_RADIOS	real	Specifies the radius of the spheres used for the mesh parameters, following the same approach as for the finite element mesh.
PARAM_EDGES	real	Sets the element edge length used for the mesh parameters, as in the finite element mesh. The edge length must be smaller than the sphere radius.