grdfile_top [grdfile_bot]

Grid file whose gravity effect is going to be computed. If two grids are provided then the gravity/magnetic effect of the volume between them is computed.

-Cdensity

Sets body density in SI. This option is mutually exclusive with -H

-Fxy_file

Provide locations where the anomaly will be computed. Note this option is mutually exclusive with -G.

-Goutgrid

Output the gravity anomaly at nodes of this grid file.

-Ethickness

To provide the layer thickness in m [Default = 500 m].

-Hf_dec/f_dip/m_int/m_dec/m_dip -H+m<magfile> -Hx|y|z|h|t -H+i|+g|+r|+f|+n

Sets parameters for computation of magnetic anomaly (Can be used multiple times).

OR for a grid mode

To compute a component, specify any of:

-Ixinc[unit][+e|n][/yinc[unit][+e|n]]

x_inc [and optionally y_inc] is the grid spacing. Optionally, append a suffix modifier. Geographical (degrees) coordinates: Append m to indicate arc minutes or s to indicate arc seconds. If one of the units e, f, k, M, n or u is appended instead, the increment is assumed to be given in meter, foot, km, Mile, nautical mile or US survey foot, respectively, and will be converted to the equivalent degrees longitude at the middle latitude of the region (the conversion depends on PROJ_ELLIPSOID). If y_inc is given but set to 0 it will be reset equal to x_inc; otherwise it will be converted to degrees latitude. All coordinates: If +e is appended then the corresponding max x (east) or y (north) may be slightly adjusted to fit exactly the given increment [by default the increment may be adjusted slightly to fit the given domain]. Finally, instead of giving an increment you may specify the number of nodes desired by appending +n to the supplied integer argument; the increment is then recalculated from the number of nodes and the domain. The resulting increment value depends on whether you have selected a gridline-registered or pixel-registered grid; see App-file-formats for details. Note: if -Rgrdfile is used then the grid spacing has already been initialized; use -I to override the values.

-Lz_obs

Sets level of observation [Default = 0]. That is the height (z) at which anomalies are computed.

-Q[nn_pad]|[pad_dist]|[<w/e/s/n>]

-Rxmin/xmax/ymin/ymax[+r][+uunit] (more ...)

Specify the region of interest. Note: this overrides the source grid region (Default: use same region as input)

-Sradius

Set search radius in km (valid only in the two grids mode OR when -E) [Default = 30 km]. This option serves to speed up the computation by not computing the effect of prisms that are further away than radius from the current node.

-V[level] (more ...)

Select verbosity level [c].

-Zlevel[b|t]

level of reference plane [Default = 0]. Use this option when the triangles describe a non-closed surface and the volume is defined from each triangle and this reference level. An example will be the water depth to compute a Bouguer anomaly. Use -Zb or Zt to close the body at its bottom (for example, to compute the effect of a dome) or at its top (to compute the effect of a spoon).

-fg

Geographic grids (dimensions of longitude, latitude) will be converted to meters via a "Flat Earth" approximation using the current ellipsoid parameters.

-x+a|n|-n

Choose the number of processors used in multi-threading (Only available with multi-threading builds).

-^ or just -

Print a short message about the syntax of the command, then exits (NOTE: on Windows just use -).

-+ or just +

Print an extensive usage (help) message, including the explanation of any module-specific option (but not the GMT common options), then exits.

-? or no arguments

Print a complete usage (help) message, including the explanation of all options, then exits.