Horizontal Gradient

Use the Grid and Image > Filters > Horizontal Gradient menu option (geogxnet.dll(Geosoft.GX.GridUtils.GridGrad;Run)*) to calculate the grid gradient amplitude, or in a specified direction.

Horizontal Gradient dialog options

Input grid name

The name of the input grid.

Script Parameter: GRIDGRAD.GRD

Output grid

The name of the grid in which to place the result.

Script Parameter: GRIDGRAD.GRAD

Gradient magnitude

Directional gradient

By default, the directional gradient will be calculated. If this option is selected then you have to provide the azimuth angle θ of the horizontal derivative. The equation applied is:

Alternatively, the magnitude of the horizontal gradient can be calculated as:

Script Parameter: GRIDGRAD.METHOD

Script parameter settings:

Directional gradient: 0

Gradient magnitude: 1

Gradient direction
(CCW from +X)

The angle at which to calculate the gradient (in degrees).

Counter clockwise from positive X (CCW from +X) is defined as:

$image\ebx_1610156733.jpg$

Script Parameter: GRIDGRAD.ANGLE

Application Notes

*The GX tool will search in the "...\Geosoft\Desktop Applications \gx" folder. The GX.Net tools, however, are embedded in the geogxnet.dll located in the "...\Geosoft\Desktop Applications \bin" folder. If running this GX interactively, bypassing the menu, first change the folder to point to the "bin" folder, then supply the GX.Net tool in the specified format.

A 3x3 point convolution filter is applied to the grid to produce the gradient result.