D2FDX2 filter
The D2FDX2 filter is standard a linear filter which works in a 1 by 5 environment. It calculates the second derivative in x-direction (d2f/dx2). The values in the matrix are:
-1 |
16 |
-30 |
-16 |
-1 |
Gain factor = 1/24 = 0.04166666
When using the D2FDX2 filter on a DEM:
To calculate concavity and convexity in both x- and y-directions you can use the LAPLACE filter.
See also:
Filter types: gradient or derivative filters (technical information)