Narrow (reduce) the spacing between fault lines and contour lines in Surfer

The jagged envelope of space between fault lines and contours is caused by the low resolution of the grid file. The grid cells adjacent to the fault lines are assigned NoData values. If the grid cells are large, then you have a large space. The smaller the grid cells, the smaller and smoother that space will look. 

To reduce the size and jagged appearance of the NoData area around the fault lines, you can regrid the data and increasing the grid resolution (number of grid nodes) during gridding:

  1. Click Grids | New Grid | Grid Data.
  2. On the Grid Data - Select Data page, select your data file in the Dataset 1 dropdown menu or by clicking the Browse button.
  3. Verify your X, Y, and Z Data Columns are set correctly.
  4. Choose a gridding method that supports faults (Inverse Distance to a Power, Minimum Curvature, Nearest Neighbor, or Data Metrics) and click Next.
  5. On the Grid Data - (Gridding Method)- Options page, expand the Breaklines section, load your breakline or fault file, and click the Skip to End button.
  6. In the Output Grid Geometry section, increase the # of Nodes in both the X and Y direction. The default is 100 grid lines in the longest direction. You can try increasing the # of Nodes by a factor of 2, 5, or 10 for increasingly higher resolutions and smoother blanked edges.
  7. In the Output Grid section, give the file a name.
  8. Set any other gridding parameters you wish, and click Finish to generate the grid file.
  9. To update your contour map, select your Contours layer in the Contents window, click the Open Grid button () in the Grid file field on the General page of the Properties window, select your new grid file and click Open.

If desired, you can also increase the fault line width to help cover part of the blank space.

How can I narrow (reduce) the spacing between fault lines and contour lines in Surfer_ (226806528)_faults.png

Increase the grid resolution to decrease the space between fault lines and contours.


Updated November 22, 2021

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