[GRASS-user] New addon: r.denoise. Denoise topography including SRTM

[Frank Broniewski]

Hi John,

I want to try your module with my srtm data, but I always get out of memory 
messages. Maybe I am just to ambitious with my region settings :-) , but could 
you provide some hints on general memory usage?

Or should I program a script for a moving window so I get smaller regions? Are 
there any problems then on the connecting borders, e.g. differnently smoothed 
surfaces at the edges?

// messages and script call ...
r.denoise in=dgm out=dgm_denoise iterations=5 threshold=0.99
...
n1: 5
n2: 50
Read Model...
Triangulation...
Error:  Out of memory.



Many thanks

Frank


On Monday 17 August 2009 17:35:15 John A Stevenson wrote:
> Hi,
>
> I've uploaded a new module, r.denoise, to the addons repository.  The
> module can be used to remove noise/speckle from DEMs including SRTM
> data.  Removing noise can improve the results from other modules e.g.
> r.watershed, r.slope.aspect.  Compared to mean/median filtering with
> r.neighbors, r.denoise makes much smaller changes to the data and is
> able to preserve sharp edges.
>
> The module is most easily installed on grass-6.5.svn via the command:
>
> g.extension r.denoise
>
> however, being a shell script, it can also be downloaded and copied to a
> directory on the path.
>
> Further information:
>
> Addons page:
> http://grass.osgeo.org/wiki/GRASS_AddOns#r.denoise
>
> Article in press in Geomorphology describing use of the denoising
> algorithm on Lidar, TOPSAR and SRTM.
> http://dx.doi.org/10.1016/j.geomorph.2009.07.006
>
> Enjoy,
>
> John