Friday, February 13, 2015

KARI Lunar Orbiter Cont'd (4)

While preparing this mission concept, I also took the opportunity to generate a fresh 32k normal map of the Moon using the latest 2014 LOLA data.
A previous version from 2011 is available from and also the Celestial Motherlode.

Like the 2011 version, I used LDEM_128.IMG from here:
Then I used Fridger Schrempp's nmtools to generate a DXT5nm virtual texture. I took the opportunity to compile nmtools again for the Mac in order to try out nmtilesDXT (a nmtools program that generates DXT5nm tiles). This worked, although I had to change the Makefile and also compile NVIDIA texture tools from scratch.

Anyway here is a side-by-side comparison of the original 2011 version vs the 2014 normal map generated by me:

As you can see, there is a clear improvement in quality in the 2014 data.
Details are sharper, and there are less artifacts as compared to the 2011 data. It goes without saying that the DXT5nm compressed format also saves disk space: 589 MB vs 946 MB for the 2011 version (which uses PNG).

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