On the left is the original green planar surface, with non-uniformly-spaced grid lines.
In the middle is a blue planar surface created by extending the original surface by adding 11 cells at the lower edge. Since the cell spacing in the original surface is non-uniform, the extension is wider on one side than the other.
On the right is a red planar surface created by extending the original surface a constant distance. No new grid lines are added between the end of the original surface and the extended surface.
Last updated 27 Feb 2003