Create Surface

Surfer can now automatically create surfaces for each contact you have defined from your drillhole data. These surfaces, which are visible in the 3D view, are defined by the contact points and can be further customized. Before creating surfaces, you must first create contacts for your drillholes using Create Contact.

Creating and Managing Surfaces

You can create surfaces for all contacts or for individual contacts. To access these options, select the Contacts group or an individual contact within the Drillhole | <Drillhole Layer Name> | Contacts section of the Contents window. In the Properties window select the General tab to view the surface creation options.

You can define the type of contact as either Depositional or Erosional. This setting is crucial as it helps determine how the surface interacts with other surfaces, establishing cross-cutting relationships. The relative age of the contacts is defined by their order in the Create Contacts dialog, with the youngest at the top.

To create surfaces for all contacts, in the Contents window select the Contacts group, then in the Properties window, select the General tab.
- Create surfaces for all contacts: Check this box to automatically generate a surface for every contact in the group. If the checkbox has a minus () it indicates that surfaces have been created for some but not all contacts.
To create surfaces for individual contacts defined in the Contents window, select the specific contact you want to create a surface for in the Contents window. In the Properties window, select the General tab.
- Create surfaces : Check this box to automatically generate a surface for every contact in the group. If the checkbox is partially filled, it indicates that surfaces have been created for some but not all contacts.
  - Of note
    - If Create surfaces for all contacts was checked, then this is automatically checked.
    - If Create surfaces for all contacts is unchecked, then this is also automatically unchecked.
    - If you check this for some surfaces then Create surfaces for all contacts is set to a minus. ()
    - If you check this for all surfaces then Create surfaces for all contacts is automatically checked.
    - These check boxes no NOT control whether or not the topography or base surfaces are created. These check-boxes (as part of the Contacts group) only controls whether the contact surfaces are created.
- Type : You can change the contact type (Depositional or Erosional) here. Changing this property will automatically update the generated surface.
  - Depositional: Depositional surfaces cannot cut into an underlying older unit, please note there is only one contact point per unit per drillhole.
  - Erosional: Erosional surfaces can cut into an underlying older unit, please note there is only one contact point per unit per drillhole

Surface Properties - General Tab

When you select an individual surface in the Contents window, the Properties window will display a General tab for that contact's surface.

You can edit the individual surfaces created from contacts. To access these options, select the individual surface within the Drillhole | <Drillhole Layer Name> | Surfaces section of the Contents window. In the Properties window select the General tab to view the surface editing options.

Color: The surface's color can be customized. By default, surfaces created from a keyword method inherit the color of the lower interval, while others default to the contact symbol color. The topography surface defaults to brown, and the base surface defaults to 50% black.
Opacity: This property allows you to set the surface's transparency, with a default of 100% (fully opaque). The topography surface has a default of 90%.
Minimum distance below: This value defines the minimum thickness of a unit, ensuring a minimum distance between this surface and the surface below it.
Save grid: Click and the standard Save Grid As dialog appears so you can save the grid file for that surface.

Surface notes

You can use Copy Format and Paste Format with surfaces.
Surfaces can be exported to 3D PDF and VRML.
Surfaces and the individual surfaces both have context menus

Creating Topography and Base Surfaces

In addition to contact surfaces, you can create topography and base surfaces. To do this, in the Contents window select the Surfaces group and in the Properties window select the General tab.

Topography: To create a topography surface at the top of the model, check the Create surface box under Topography. You can then select a data source for the surface:
- Top of drillhole: Uses the top of the drillhole, or the Z value in the Collars table..
- Start depth: Uses the starting depth from the collars table.
- First data: Uses the first data point from the surface, note that this may not be at the top of the hole.
- Grid file: Allows you to load an existing grid file for the ground surface.
Base: To create a surface at the base of the model, check the Create surface box under Base. You can choose a data source for the surface:
- End depth: Uses the end depth values from the collars table.
- Last data: Uses the last data point from the drillhole, note that this may not be at the bottom of the hole.
- Grid file: Allows you to load an existing grid file for the base surface.

Gridding Options - Gridding Tab

The Surface Gridding tab, available when a Surfaces group is selected, offers key gridding controls.

Gridding method: You can choose from methods such as Inverse Distance to a Power, Kriging, and Radial Basis Function. The default method is Radial Basis Function, as it is well-suited for most datasets.

Golden Nugget : If you want to use a different gridding method or advanced options, export the contact points and grid the contact points using Grid Data and then add that grid back as a layer to the map.

Assign NoData outside of: This property allows you to set areas of NoData. Options include None, Convex Hull, and Alpha Shape.
# of Nodes and Spacing: These properties control the resolution of the grid. Changing one will automatically update the other.
- # of Nodes : Default is 200 for both X and Y nodes.
- Spacing : Default is based on the extents and the # of Nodes.

Gridding Notes

If for any reason the gridding can’t be completed, a warning or error will be issued.
Note that for deviated holes, the Hole Deviation source/TVD method is inherited from the drillhole layer itself in the 2D view.

Saving Surfaces

You can save your created surfaces as .GRD files for use in the 2D plot window or other applications.

Save Grid

This is available if an individual surface is selected in Contents under Drillhole | Drillhole | Surfaces. Click Save Grid and the Save Grid As dialog will to allow you to specify a location and grid type to save the grid file for that surface.

Save All Grids

This is available if the Surfaces group or an individual surface is selected in Contents under Drillhole | Drillhole. To save all contact, topography, and base surfaces at once, click the Save All Grids button in the ribbon. The Save All Grid(s) dialog will open and prompt you to choose a folder location to save all the .GRD files, and the format for the grid files.

Conflicts - Conflicts Tab

The Conflicts tab, available when a surface is selected, provides information about any inconsistencies or errors during gridding. A "gridding conflict" occurs when features or coordinate systems have discrepancies as they are projected onto a grid. The tab lists several fields to help you understand what caused these issues and how Surfer resolved them.

Type. Identifies the nature of the conflict.
- Gridding error. This occurs when there's an issue with the gridding options, such as an inappropriate alpha value for the alpha shape. Instead of getting an error and no surfaces, the alpha shape simply isn’t applied.
- Surface conflict. This is typically an issue with the contact points in a specific drillhole (e.g., the younging order is reversed from expectedor if the surface generated from one contact crosses the contact points or surface for another contact
Identifier. Pinpoints the source of the conflict. This might be a Hole ID if the problem is related to specific contact points, or it could indicate the gridding option that caused the issue.
Description. A detailed explanation of the gridding issue.
Resolution. Explains how Surfer automatically resolved the conflict..

Conflict Notes

The fields in the Conflicts tab will adjust to the window's width. Although text may appear cut off because it doesn't wrap, hovering your mouse over any of the fields will display the entire text.