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Logging Structures

Insight has support for logging planar and linear structures, using the tomographic 3D image of the core as a guide.

Note

When starting the program, structures are initially hidden. Logged structures can be shown and hidden using the Show → Structures check box in the menu bar.

Tip

The orientation of each logged structure is defined by a set of internal and (optionally) global orientation angles. For more information on these angles, see Structure Orientations.

Caution

Structures are saved as part of the Project; remember to always save your project, to not lose any annotated structures.

Adding Structures

Structure additions are initiated from the Structures Toolbar, which is shown in the top part of the window when structures are shown (see above):

Toolbar

Two complementary modes are offered:

  1. Clicking the Palette button brings up the Structure Palette floating window:

    Palette

    This mode is well suited for logging a wide selection of different structure types, as both categories (linear and planar) and all corresponding types (e.g. "Fold Axis" and "Foliation") are available through a single button click.

  2. Selecting the category (linear or planar) and the corresponding type (e.g. "Fold Axis" and "Foliation") directly in the Structures Toolbar:

    Linear Box

    Planar Box

    Once selected, pressing Ctrl initiates addition of the selected combination. This mode is well suited for logging a large number of the same structure type, as the same structure type can repeatedly added by simply pressing Ctrl.

Specific instructions for logging linear and, respectively, planar category structures follows below.

Adding Linear Structures

  1. Select the segment containing the structure you wish to log (see Selecting a Segment). For example in this case, a stretching lineation:

    Stretching Lineation

  2. It's easiest to identify stretching lineations with the view direction orthogonal to the structure direction (A):

    Stretching Lineation

    To log a linear structure, begin by aligning the viewing direction of the view to the structure direction (B). The linear structure should be shown as a point.

  3. Initiate the addition of a linear structure type, through one of the two modes described above.

    If the type of structure you wish to add is not in the list, pick Other. You can later add a comment describing the structure, which will be preserved when the structures are exported (see Changing Structure Type and Comment below).

  4. Using the left mouse button, click on the aligned linear structure in the 3D Tomography view to add the structure:

    Adding Linear

  5. The linear structure is now added and represented by a thick line in 3D:

    Linear Result

    Tip

    To abort an ongoing structure addition, linear or planar alike, simply press Escape on the keyboard.

Adding Planar Structures

  1. Select the segment containing the structure you wish to log (see Selecting a Segment). For example in this case, a cross-cutting shear zone within a quartz-feldspar matrix:

    Shear

  2. Align the viewing direction of the 3D Tomography view to the structure direction (as above).

  3. Initiate the addition of a planar structure type, through one of the two modes described above.

    If the type of structure you wish to add is not in the list, pick Other. You can later add a comment describing the structure, which will be preserved when the structures are exported (see Changing Structure Type and Comment below).

  4. Using the left mouse button, click on two points in the 3D Tomography view to add the structure:

    Adding Shear

  5. The structure is now added and represented by an elliptical disc in 3D:

    Shear Result

    Tip

    The elliptical stretch of the disc increases with the acuteness of α (see Internal Orientations in the Structure Orientations section), simulating the behavior of a physically cut cross-section. Together with the dashed-line marker of the major axis, this helps to visually gauge the "steepnees" of the structure w.r.t. the core axis.

Removing Structures

  1. Select the structure by clicking on its outline in the 3D Tomography view. The structure outline will turn thicker to indicate that the structure is selected:

    Selected Structure

    A description of the selected structure will also be shown in the status bar at the bottom, including its depth and orientation angles. For an explanation of these angles, see the Structure Orientations section.

  2. Press Delete on the keyboard to remove the selected structure.

  3. If you have many structures to remove, it's more convenient to use the Structures Toolbox available from Toolboxes → Structures in the menu bar. This will show a table of all structures, where multiple structures can be selected using Shift/Control + Left Mouse Button. Pressing the Remove button will remove all selected structures:

    Removing Structures

Changing Structure Type and Comment

Added structures can have an associated comment. If you want to change the type or comment for a structure:

  1. Bring up the Structures Toolbox using Toolboxes → Structures in the menu bar.

  2. Double-click a Type cell to bring up a drop-down to select the structure type:

    Changing Type

  3. If you want to describe a structure in more detail, you can double-click a Comment cell to enter a free-text comment:

    Changing Comment

    Confirm the change by pressing Enter or clicking outside the cell.

For information on how to export the logged structures to CSV (Comma Separated Values), see Exporting Structures.