Figure 7. Calculation of a faces file with the EarthVision modeling software for the Wakulla Spring cave system developed in the Floridan aquifer, north Florida. Shades of gray reflect contours of the modeled parameter (depth). The calculation involves (A) a three-dimensional grid of depth values measured in the cave system; (B) clipping with a two-dimensional grid of points describing the upper part of the cave system; (C) clipping with a two-dimensional grid of points describing the lower part of the cave system; and (D) clipping with a polygon constructed from points describing the outermost perimeter of the cave system.