I'm trying to render a portion of the south pole of the moon, using DEM from the LRO mission.
I'm seeing horizontal banding in the renders.
When I look at the DEM, I'm not seeing any banding.
I suspect it's a displacement artifact.
I have tried all the geometry dicing settings, but they don't make any difference.
I also made sure the displacement bounds is larger than the displacement amount.
What am I missing?

It turns out there ARE artifacts in the DEM, I couldn't see them when viewed in an image viewer.
My workaround is to blur the texture in the displacement material: Texture/Filter Width 1->25

For anyone interested in DEM, here is a paper on minimizing scanning artifacts:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.470.4960&rep=rep1&type=pdf [citeseerx.ist.psu.edu]