2.0 Model Layers

2.1 Adding a layer

To add a new layer to the model navigate to the ‘Layers’ menu and select ‘New Layer’:

Layers -> New Layer -> New fixed layer
                    -> New floating layer

Alternatively, use the keyboard shortcut, n key.

You will be prompted with the option of adding a ‘New fixed layer’ or a ‘New floating layer’.

Floating layers:

Floating layers are polygons that are fully contained within the model space. For example, a narrow salt dome.

Warning

Floating layer nodes must be input anti-clockwise otherwise the calculated anomaly will have the wrong sign!

Fixed layers:

Fixed layers span the entire width of the model and may useful for modelling features such as sedimentary basins. Fixed layers have fixed boundary nodes that can only be moved vertically along the model edges.

Note

Fixed layers are automatically ‘padded’ horizontally from the boundary nodes by an additional 400 km in order to avoid edge effects.

2.2 Adding a new node to a layer

To add a node to a layer place the mouse cursor at the position where you would like to add the new node and press the ‘i’ key to insert the new node.

Note

Nodes are inserted to the right of the currently selected node (which is highlighted red).

2.3 Deleting a node from a layer

To delete a node from a layer place the mouse cursor over the node you would like to delete and press the ‘d’ key to delete the node.

2.4 Pinching nodes

“Pinching” refers to “snapping” a node onto a node of another layer so that they are “stuck” together.

There are two ways to pinch nodes together:

1. To pinch a single node, press the p key to activate pinch mode. Now select the node you wish to pinch, then switch to the layer which you would like to pinch to, finally select the node to pinch to.

2. Alternatively, multiple nodes can be pinched or depinched simultaneously to the layer above or below (as defined in the layer order list) by selecting ‘Pinch Layer’ in the Menubar. A distance range over which to pinch/depinch nodes can then be entered and the user can select ‘Pinch up’ or ‘Pinch down’ to pinch out onto the upper or lower layer respectively. This is useful when modelling fixed layers and you would like to pinch a layer out.

2.5 Deleting a layer

To delete a model layer, in the Menubar navigate to:

Layers -> Delete Current Layer...