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Wireframe Maps

Wireframe maps are three-dimensional representations of a grid file or digital elevation model (DEM). They're created by connecting Z values along lines of constant X and Y. At each XY intersection (grid node), the height of the wireframe map is proportional to the Z value assigned to that node. The number of columns and rows in the grid file determines the number of X and Y lines drawn on the wireframe map.

Wireframe maps can display any combination of X lines, Y lines, or Z contour lines. On the wireframe map, X lines correspond to the columns in the grid file and Y lines correspond to rows in the grid file. When displaying contours on the wireframe map, the contour lines (lines of equal Z value on the surface) are drawn at the appropriate elevation on the surface. This type of map is also sometimes called a stacked contour plot because the contour lines are stacked one over another on the surface.

The smoothness of wireframe maps is a function of the density and topography of the grid. For example, a 10 by 10 grid file (ten rows and ten columns) appears much more angular than a 50 by 50 grid file created from the same data.

Increasing the number of grid rows or columns should improve angular wireframe maps. One method is to create a new grid file with more lines in the X and Y directions. Alternatively, sophisticated software such as Surfer allows you to use a spline smoothing function to insert additional rows and columns into an existing grid file. This obviously saves considerable time when dealing with large data sets. (Note: Surfer also has a matrix smoothing function which can be used to increase the smoothness of the map)

Blanked regions of a grid file are represented by low flat areas on a wireframe map and can wreak havoc with results if not treated correctly. It is recommended that the level of the blanked region is set to the minimum Z value for the grid file. For example, consider a blanked grid file that ranges from 45 to 100 in the Z dimension. When a wireframe map is displayed, the blanked region appears as a large flat area at the Z=45 elevation.