Curvature raster map problem

[TomaszBartus]

Hi!

I have posted the question about my curvature tool problem to raster subforum (http://forums.arcgis.com/threads/79818-Curvature-raster-map).

I do not want to multiply messages and therefore, please to use the external link

Tomasz Bartu�?

[TomaszBartus]

The problem is still unsolved.
I think it's not a fail DEM problem.

Fig. 1. DEM
[ATTACH=CONFIG]23440[/ATTACH]

Fig. 2. Total curvature grid layer
[ATTACH=CONFIG]23441[/ATTACH]

Fig. 3. Topographic Wetness Index (TWI) / Compound Topographic Index (CTI) / Catchment Wetness Index (CWI)  (DEM derivative) - the same problem with pixels with extreme values which looking like chess board.

[ATTACH=CONFIG]23442[/ATTACH]

maybe there is an intelligent way to smooth the grids? any ideas?

[TomaszBartus]

How to perform a smoothing of the grid surface by the Fast Fourier Transform (FFT) (Preferably using free applications)?
I know that this can not be done directly in ArcGIS.

- It'll be probably possible to do with Oasis Montaj (I do not have the app) and Surfer (http://www.cas.umt.edu/geosciences//faculty/sheriff/495-applied%20magnetics/sources/threshold%20filt...),
- Idrisi?

[TomaszBartus]

It may be useful to someone!
The problem was caused by the irregular boundaries of the DEM area. When I change it to the rectangular, the problem has resolved.