Assign NoData to 3D Grid

By default, all Surfer grids are rectilinear.  Use the Assign NoData feature to limit your 3D grid to a field area boundary, outside of data collection limits, or above the ground surface so that the NoData area is not visualized in the map or the 3D view.

This allows you to:

  • Model contamination plumes, but remove the data above the surface topography, or remove the overburden from the grid

  • Only create grid data in areas where there were original data points

  • Create holes in the middle of the data set if there is no data in that area

Surfer 3D View of a 3D grid with NoData regions assigned

Assign NoData to areas in your 3D grid

 

 

How to assign NoData outside a boundary

To use this feature, all you need to start with is a data filewith columns for XYZ data and a variable. Follow these steps:

  1. Click Home | Grid Data

  2. In the first page of the Grid Data wizard,

    1. select XYZC as the Data Type

    2. click Browse, select your data file and click Open

    3. select the appropriate X, Y, Z and C data columns

    4. click Next

  3. On the second page of the Grid Data wizard, select any advanced options you wish and click Next.

  4. On the third, and final page of the Grid Data wizard, you can choose to set Assign NoData outside of to either Convex hull or Alpha shape. Alternatively, if you already have a polygon file with a 2D polygon in it, you can leave that setting set to None and then select the file under the NoData Polygon Boundary section.

    1. 4.png
      Choose to assign NoData outside the convex hull, outside an alpha shape, or either inside or outside of a polygon boundary.
  5. Give the file a name and click Finish. The 3D grid file is created with the appropriate NoData selections applied. You can use this new 3D grid to create a map and visualize in the 3D view.

1.png

Assign NoData to your 3D grid outside a 2D polygon boundary, such as an alpha shape polygon created around the original data points.

How to assign NoData below a surface

To use this feature, all you need to start with is a 3D grid file (VTK or HDF). Follow these steps:

  1. Click Grids | Edit | Assign NoData.

  2. To the right of Input Grid, click Browse, select your 3D grid file and click Open. Choose to import the file as 3D Grid.

  3. Now you can choose to assign NoData inside or outside a 2D polygon, or above or below a surface described in a 2D grid file (or both). Make your selections in the NoData 2D Polygon Boundary and the NoData Surface Boundary sections.

    1. 4.png
      Choose to assign NoData to a 3D grid file using a polygon boundary, another grid surface, or both.
  4. Give the file a name and click OK. If a 3D grid was selected for the input grid, then the output grid is automatically a 3D grid as well. The 3D grid file is created with the appropriate NoData selections applied. You can use this new 3D grid to create a map and visualize in the 3D view.

2.png

Assign NoData above or below another 2D grid surface, such as topography to remove the gridded data above the ground surface.

 

 

 

 

Was this article helpful?
2 out of 2 found this helpful

Comments

0 comments

Article is closed for comments.