The slant plane has a 30[degrees] angle with the horizontal plane.
Figure 13 shows the spatial distribution of the percentage distance errors associated with the four methods for the 30[degrees] slant plane shown in Figure 10.
Buffers of 50-unit width are also delineated with the 30[degrees] slant plane methods shown in Figure 10.
The datasets include three hypothetical slant planes with a single source cell at the center of the planes and a USGS 7.
All the methods are first tested on hypothetical slant planes having different angles (0, 15[degrees], 30[degrees], 45[degrees], 60[degrees], and 75[degrees]) with the horizontal plane (Figure 10).
An elevation difference raster layer is then calculated by subtracting the constant raster layer from the slant planes.
Table 6 shows the mean errors associated with the four methods on the six slant planes.
Tables 7 to 10 show the accuracy and commission, omission, and total errors associated with 50-unit buffers delineated by the four methods on different slant planes.
Analysis on the hypothetical slant planes reveals that topo-distance is not perfect.