Grid Node Definition
A grid is a rectangular region comprised of rows and columns. A grid node is the intersection of a row and column in the grid file. Each grid node is represented by a Z value that indicates the height of the grid at that point.
Each grid node is indicated with a black "+" in the grid editor window. Each NoData node is indicated with a blue "x" in the grid node editor. The selected grid node is displayed with a red diamond around the grid node.