[Gvsig_english] DEM generating

[Antonio Falciano]

Dietrich Schröder ha scritto:
> Yes, the workflow will give some results. I've used this workflow to
> create a DEM. Unfortunately, the DEM will be not of high quality, as the
> "steps" due to the line structure can clearly be seen in the DEM.

Sincerely speaking, I don't like this approach because it's so much
deterministic and "Void filling" tool is too much slower to interpolate
several No Data values, especially when cell size is high and/or raster
extent is big. It seems like a proof of concept.
An alternative way consists into conversion of contour lines into points
by "Line to equispaced points" tool and the application of an
interpolation method (e.g. IDW). Finally, if the result raster has some
No Data values (only in this case!), we can use "Void filling" tool.

> The results would be much better, if not all the rasterized pixel from
> the contours will be used, but a randomly distributed number of pixels.
> Unfortunately, such a tool to pick a random number of pixels doesn't
> exist up to now in Sextante. Hope it will be added in the future!

There's a function rand() in the Raster Calculator tool that returns a
value between 0 and 1. You could use it for a mask and so on...
Hope this helps!

Cheers,
Antonio

-- 
Antonio Falciano
http://www.linkedin.com/in/antoniofalciano