Tim Cook <z99### [at] gmailcom> wrote:
> On 2012-10-17 17:33, Samuel Benge wrote:
> > If none of that works, would you mind posting your entire height map so I can
> > figure out what's going wrong?
>
> The original height map I rendered at 7200x4800, so it's a 2.4 MB png,
> here's the reduced-size version.  (Ehm, re-rendered...oh hey, I had
> jitter 'on' in the antialiasing options there, that might've been
> contributing to the noise level, let's see what it turns out with that
> off.)  *waits*
>
> Here we go.

Thanks, I'll see how it works out over here.

I noticed that your map uses elements of varying resolutions. Some parts are
sharp, while others are quite pixelated. That could be a big source of your
problems. AFAICT, noise reduction schemes assume that the noise is at or near
the pixel level (ie. sudden changes occur from one pixel to the next). If abrupt
changes occur over several pixels, you're going to have problems trying to
smooth things out.

There must be a magnification filter somewhere that can smooth the transitions,
like some sort of HQNx filter for height maps.

> Ah!  A problem your macro doesn't take into account (not sure how it
> would, either, but who knows?) is that of depressions, where a given
> contour line loop isn't an ascending hill, but a shallower area.

It should. The attached render uses a converted and eroded digital elevation
model of Morongo Valley, CA (elevation lines were arbitrarily chosen). Near the
far upper right you can just make out an irregular depression ringed by a blue
line. Depressions in the desert aren't easy to come by--all the water flows down
hills and ravines--and consequently that is the only one I have found on this
particular map so far.

My macro takes everything literally, so a line is just as likely to loop around
a depression as it is a hill, it's just that depressions are less common and
might be missed if the spacing is too wide.

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