Mars NormalMaps from MOLA data
Posted: 05.07.2008, 20:36
Hi all.
I have written a set of Perl scripts that read the MOLA elevation data for Mars, stitch together a large map (up to 46K), and use Fridger's NMTools to generate NormalMaps, either regular or a complete VT ready for use. I did this for my personal use, but the high resolution results are so beautiful, that I documented them and am making them public. They are easy to use even if you don't speak Perl. They are available at the Celestia section of my page. The readme file and the scripts themselves explain what you need and how to proceed. I put there a few screenshots, and am inserting just one below.
Some details now.
MOLA data are distributed by the Planetary Data System through its Geosciences node. The necessary files are the 128 pixels per degree topographic as well as the 64 ppd ones. (They are here.) They are distributed as tiles of 16 bits per pixel binary images. The scripts make the tedious job of stitching them together.
The 128 ppd set covers Mars from Latitude 88N to 88S. So, to make a 46K map I use the 2 degrees around the poles from the 64 ppd set. The results show that these data are probably spurious, but I still decided to just use the data and not retouch them, at least for now. The resulting 46K x 16 bits elevation map can be fed to NMTools to make high quality, geometrically correct NormalMaps up to 32K, exquisitely detailed. They are ideal to be used with a very flat surface texture, such as the one by Mario Rossi from Space Graphics.
You can also generate lower resolution maps just from the 64 ppd set, which is a smaller download from PDS. Whith it, you can make a 16K VT NormalMap, which is very decent. Regular NormalMaps (not VT) can also be easily made from this one, 2K, 4K, 8K, as you please, to replace the official Mars bump file. With these fantastic data available, I believe that we could just distribute Celestia with a 2K Mars NormalMap.
One can easily adapt these scripts to generate NormalMaps of other planets distributed in the same format. The PDS has just informed of a new Clementine Mapping Project, that provides some "improved" lunar maps (the topographic map is explained in this paper). I tried to use that map, which is said to be 16 bit raw, but something is not working, because the NormalMap does not results well. Anyway, I downloaded the elevation png they distribute, and the resolution is not very good, so perhaps it's not worth. Perhaps we can just wait until the Japanese or the ESA release their own measurements. If anyone succeeds with Luna, please let me know...
Enjoy, and let me know if you use it, and certainly if you like it!
Guillermo
PS: Fridger & Robert, thanks again for the NMTools!
I have written a set of Perl scripts that read the MOLA elevation data for Mars, stitch together a large map (up to 46K), and use Fridger's NMTools to generate NormalMaps, either regular or a complete VT ready for use. I did this for my personal use, but the high resolution results are so beautiful, that I documented them and am making them public. They are easy to use even if you don't speak Perl. They are available at the Celestia section of my page. The readme file and the scripts themselves explain what you need and how to proceed. I put there a few screenshots, and am inserting just one below.
Some details now.
MOLA data are distributed by the Planetary Data System through its Geosciences node. The necessary files are the 128 pixels per degree topographic as well as the 64 ppd ones. (They are here.) They are distributed as tiles of 16 bits per pixel binary images. The scripts make the tedious job of stitching them together.
The 128 ppd set covers Mars from Latitude 88N to 88S. So, to make a 46K map I use the 2 degrees around the poles from the 64 ppd set. The results show that these data are probably spurious, but I still decided to just use the data and not retouch them, at least for now. The resulting 46K x 16 bits elevation map can be fed to NMTools to make high quality, geometrically correct NormalMaps up to 32K, exquisitely detailed. They are ideal to be used with a very flat surface texture, such as the one by Mario Rossi from Space Graphics.
You can also generate lower resolution maps just from the 64 ppd set, which is a smaller download from PDS. Whith it, you can make a 16K VT NormalMap, which is very decent. Regular NormalMaps (not VT) can also be easily made from this one, 2K, 4K, 8K, as you please, to replace the official Mars bump file. With these fantastic data available, I believe that we could just distribute Celestia with a 2K Mars NormalMap.
One can easily adapt these scripts to generate NormalMaps of other planets distributed in the same format. The PDS has just informed of a new Clementine Mapping Project, that provides some "improved" lunar maps (the topographic map is explained in this paper). I tried to use that map, which is said to be 16 bit raw, but something is not working, because the NormalMap does not results well. Anyway, I downloaded the elevation png they distribute, and the resolution is not very good, so perhaps it's not worth. Perhaps we can just wait until the Japanese or the ESA release their own measurements. If anyone succeeds with Luna, please let me know...
Enjoy, and let me know if you use it, and certainly if you like it!
Guillermo
PS: Fridger & Robert, thanks again for the NMTools!