Tim Cook <z99### [at] gmailcom> wrote:
> Well, a little bit of progress, but something's obviously not right...
>
> Here's what I've got now, with tamrielheightsmall.png being a straight
> height-gradient render.
>
<snip>
> ...and this is what it comes out as.  (there's some weird noise at the
> top and bottom that's there even with just using InputPigment as the
> pigment, and the contour lines are all noisy)

Alright, after scratching my head for a while I've determined that the problem
is with your height data. I zoomed up on an unlined portion of your image and
saw a lot of noise; rendered it with Pg_Elevation_Lines, and got similar results
as yours.

So to get rid of the noise, try one of these options:

1) Open the height map in Gimp, and apply the Despeckle filter using its default
settings. Unfortunately, Gimp does not (yet!) support 16-bit grayscale.

-or-

2) Render your height map in POV-Ray using these command line options: +fng +f
+a0.01 +am2 +r3 This seems to be more accurate than Gimp's Depseckle filter,
although POV-Ray still cannot match the gamma of the original image, so
calculating the proper line spacing and offset with Pg_Elevation_Lines might
prove difficult.

Other program options include PhotoShop, Terragen, Wilbur, or any other program
that can manipulate 16-bit height maps.

Since I was unable to render your entire height map, I cannot say for certain if
the noise reduction techniques I tried would completely get rid of all the
artifacts, so you may need to tweak some settings here and there (interpolating
the image in POV-Ray comes to mind).

Sam

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