Available with 3D Analyst license.
Surface Difference works by performing ageometric comparison between the triangles of both input surfaces.The triangles from the first surface are classified as eithercompletely above, below, or intersecting the second (reference)surface. When intersections are detected, triangles get subdividedinto portions that are classified as above, below, or coplanar tothe other surface. Contiguous triangles, and triangle parts, thathave the same classification are grouped into polygons, and theirvolumetric contributions are summed to provide a total for each ofthese polygons. This information is then written to the outputpolygon feature class.
The difference surface is constructed using constrained Delaunay triangulation while performing the geometric comparisonbetween the two input surfaces. The z values of this surface represent the heightdifferential between the input surfaces. Z values of 0.0 occurwhere the input surfaces have coincident values. Positive values denote the areas where the first surfaceis above the second (reference) surface, and negative values reflect areas where the first surface is below the second.
When a difference raster is requested,the tool converts the triangulated difference surface to a raster usinglinear interpolation.
When an output TIN folder is specified, thetriangulated difference surface will be written as a TIN to the specified workspace. If the resulting surface would contain too many nodes for one TIN to store, the tool may outputmultiple TINs.
