How to: Calculate the gravity response within a GM-SYS model cross-section and display the resulting georeferenced section grid in the 3D Viewer

Objective:

How to calculate the gravity response within a GMSYS model cross-section and display the resulting georeferenced section grid in the 3D Viewer.

Environment:

GMSYS Profile Modelling Advanced version 7.1

To calculate the gravity response:

1. Ensure your model is open in GMSYS.
2. Compute menu > Calc Geosoft Vert Grids.
3. Select "Gravity" from the Param. to grid listbox.
4. For the Output Grid parameter, enter the directory and filename for the resulting grid.
5. Set the X and Z minimum and maximum and the cell size for the grid in profile coordinates. The default limits are those of the current view.
6. Click Compute & Save

To display this section grid in the 3D Viewer:

1. In Oasis montaj > 3D menu > Create a New 3D View.
2. Specify a Map name.
3. Click OK.
4. In the 3D Viewer > Add to 3D > Grids > Plan or Section Grid(s).
5. Specify the vertical gravity grid you created for the Colour image/grid parameter.
6. Click OK.

   The section grid will be displayed in the 3D Viewer with the correct georeferencing and orientation

Notes:

Only the gravity response can be calculated within a model. The magnetic and gravity gradient calculations are undefined within a body of non-zero property.

The response at each grid node is calculated separately, so technically, no gridding algorithm is used. The grid is simply populated.

You may also export section grids containing the physical properties of the model (density, susceptibility, remnant magnetization, or velocity) using the same workflow; simply select the physical property from the Param. to grid listbox.

All grids written by GM-SYS Profile inherit the Coordinate System, location, and orientation of the model.

Cursor tracking will work from the GMSYS window to the 3D Viewer. If the link between the GMSYS window and the 3D Viewer is lost after adding new layers to the 3D Viewer, close the 3D Viewer and reopen it by clicking "Open 3D Viewer" from the Oasis montaj toolbar.