Novice: Contours from GIF [Smoothing]

James Cameron cameron at
Thu Sep 25 02:56:24 EDT 1997

Radoslav Bonk wrote:
> [...] try to run d.display [...]

Wow!  I hadn't found that program yet.  That makes things much simpler,

Aldo Clerici wrote:
> I usually use:
>    r.thin (to thins lines)
>    r.line (to create a binary vector file)
> (to build the dig_plus file)
>    v.digit (to label contour lines).

Okay, I've done all that now.  I've also gone further and attempted
to use to build a raster, then r.neighbors to smooth the
data, then r.slope.aspect and then r.cost to try and figure out an
optimal road path.  [Thanks to Ishmael Williams for that last bit].

But the contour separation varies considerably ... the land has steep
and flat sections, so r.neighbors would tend to pull down the hills
if I enlarge it's sampling area too much ... but if I don't enlarge
it enough then there are flat sections between contours that affect
the cost calculations.

How do I smooth contours without warping the data too much?

James Cameron                                    (cameron at
Digital Equipment Corporation (Australia) Pty. Ltd. A.C.N. 000 446 800

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