Build Constraints from Database Lines (NGASCONS GX)

The Build Constraints from Database Lines option (GM-SYS 3D Tools > Grid Editing menu) modifies a "constraints" grid at locations defined by a line in a database (e.g., seismic line). You specify one of seven tool shapes (e.g. cosine) and the height and width of the tool perpendicular to the line path.

The initial dialog asks the user to supply a grid name for editing, a database, a tool shape, the tool height, and the tool width. If there is no currently open map, the user is prompted to open one. The map will be redrawn after the editing to reflect the changes

To create a new constraints grid, run the New Constant Model Grid option (GM-SYS 3D Tools > Grid Editing menu) and set the constant grid value to 1. Then run this GX on that new grid using a tool height of –1. If the line crosses itself, the GX uses the smaller of the two overlapping values.

  • If you start with a grid with all the values in the grid set to 0, NGAWCONS.GX will make no changes in the grid.

    • Build Constraints from Database Lines Options

    Grid

    The name of a valid Geosoft floating point grid to edit. This grid need not be displayed on the current map

    Line DB

    The name of the Oasis GDB containing the line path.

    Edit tool

    One of 8 shapes that determine the shape to be used. Tool shape choices are: "cosine," "gaussian," "tent," "left-wedge," "right-wedge," "square-wave," "constant and "halfpipe." Each tool is centered at the point. All of the tools except "constant" add the "tool height" modified by the shape to the grid cells in the edit area. "Constant" sets the cell values to the "tool height" value in the edit area. See the User's Guide for additional details and tool shape images.

    Tool height

    Height in Z-Units, as specified by the value of the grid. (Default value –1.0.)

    Tool width

    Width in Ground Units, as specified in the Data view of the map. All tools with the exception of the "square-wave" and "constant" taper to zero at this width.

    Line Database Options

    Line

    Select the database line from the list. Only one line from the database will be processed.

    X Col

    Select the X-coordinate channel.

    Y Col

    Select the Y-coordinate channel

    Mask Col

    Select an optional mask channel. If the value in this channel is a dummy or zero, that point will be skipped. Any other value in the Mask channel causes the point to be used.

    See Also: