DFDDN filter
The DFDDN filter is standard a linear filter which works in a 5 by 5 environment. It calculates the first derivative in the downward diagonal direction (df/downward diagonal). The values in the matrix are:
1 |
0 |
0 |
0 |
0 |
|
0 |
-8 |
0 |
0 |
0 |
|
0 |
0 |
0 |
0 |
0 |
|
0 |
0 |
0 |
8 |
0 |
|
0 |
0 |
0 |
0 |
-1 |
Gain factor = 1/12 = 0.0833333
When using the DFDDN filter on a DEM:
See also:
Filter types: gradient or derivative filters (technical information)