Celestia Forums

Hi.

I have just known that the Jaxa has disclosed the much awaited data from Kaguya, including the topographical ones. Access here. I haven't gone through all the search for data yet (which is not obvious). But a guy at unmannedspaceflight.com did a render of topography in Celestia (see here). I will try find the 16 bit data and make a good normal map with Fridger's tools one of these days.

Besides, browsing Ciclops for the recent flyby of enceladus, I found they released a new map of the little moon, much better than previous ones. Find it here.

Guillermo

Oops, I just saw that our very CL posts on that thread at unmanedspaceflight.

Also, see this thread:

viewtopic.php?f=5&t=15406



The Celestia renderings on UMSF are by volcanopele, who also posts fairly frequently here. I'm working with the 16-bit Kaguya data to make a normal map. Mike Howard's seems pretty good already except at the poles. I suspect the artifacts there are in the data itself, not with his processing, but it's worth a look.

--Chris

chris wrote:Also, see this thread: viewtopic.php?f=5&t=15406

Oops again, indeed! I missed that post, dated one hour before mine
Guillermo

chris wrote:Also, see this thread:

viewtopic.php?f=5&t=15406



The Celestia renderings on UMSF are by volcanopele, who also posts fairly frequently here. I'm working with the 16-bit Kaguya data to make a normal map. Mike Howard's seems pretty good already except at the poles. I suspect the artifacts there are in the data itself, not with his processing, but it's worth a look.

--Chris

I have also been working on the new publicly released topography data of the Moon (LALT).



After registration and download of the PDS/Img data, ISIS3 can be used for conversion to 16bit signed integer raw format as needed by my nms tool. Away from the poles, the resulting normal map is really nice, while the poles show a fairly strong pinch effect.

+++++++++++++++++++++++++++++++++
Therefore I have set out to code a new pinch correction algorithm for my tools. It's based on what I learned from getting rid of the polar pinch in case of the Phobos shape model

http://forum.celestialmatters.org/viewtopic.php?t=339
++++++++++++++++++++++++++++++++++

If the new "pinch killer" tool will work satisfactorily, it will be included in my F-TexTools/nmtools.

More about all this, at CelestialMatters ...stay tuned

Fridger

t00fri wrote:After registration and download of the PDS/Img data, ISIS3 can be used for conversion to 16bit signed integer raw format as needed by my nms tool. Away from the poles, the resulting normal map is really nice, while the poles show a fairly strong pinch effect.

Mike Howard's normal map actually looks better near the poles than the one produced by nms. I suspected that he was clamping the spherical correction term for regions within 2 degrees of the poles, and he confirmed that this was indeed the case (and that it was also beneficial when processing the MOLA data.) Mike posted a new map with some filtering at the poles to further reduce artifacts there.

Therefore I have set out to code a new pinch correction algorithm for my nms tool. It's based on what I learned from getting rid of the polar pinch in case of the Phobos shape model

Excellent--this will be very useful. It won't solve all the problems in the polar regions of the LALT data set, though. I tried producing a normal map without any spherical correction applied and noticed artifacts that aren't simply noise. In several places, features that are obviously crater rims are broken into pieces, with a series of gaps regularly spaced in longitude.

--Chris

--- edit ---

t00fri's image looks very much like this image from Lunar Orbiter 4

At first I was surprised on how exaggerated the data seemed in Celestia. I suppose I'm not quite as much now.

As I emphasized already in the dev list 3 days ago, there are some very nasty artefacts in the recent LANL topography data of the Moon near the poles (notably the south pole) that are NOT pinch-related, despite looking like pinches superficially.

Here is a clearcut display of the ORIGINAL LALT elevation data near the south pole in simple cylindrical projection:



To emphasize again, these vertical bar-type artefacts are NOT related to my normalmap code (nms), since they show clearly already in the original topography map! These artefacts get however amplified in the process of forming numerical derivatives for normalmap generation.

More in CelestialMatters, soon...

Since some days, I am in correspondence with the two Japanes scientists (Drs. Araki and Ishihara) , who did the image analysis of the recent LALT data. As soon as the dust settles, you will find my conclusions in CM, as well.

Fridger

PS: Let me add that I have meanwhile succeeded in deriving an effective algorithm for eliminating most of the nasty pinch effects in normalmaps! These encouraging results you will also find very soon in CelestialMatters.

Hungry4info wrote:t00fri's image looks very much like this image from Lunar Orbiter 4

At first I was surprised on how exaggerated the data seemed in Celestia. I suppose I'm not quite as much now.

Cute

It cannot be overlooked that my above image has a little better quality, though

Fridger

--- edit ---

abramson wrote:I will try find the 16 bit data and make a good normal map with Fridger's tools one of these days.

Besides, browsing Ciclops for the recent flyby of Enceladus, I found they released a new map of the little moon, much better than previous ones.

I made both:

• Moon Normal Map based on Kaguya elevation data.
• Enceladus textures based on Ciclops 2009-10-30 map.

Enjoy.
Guillermo

--- edit ---

starwalker wrote:

abramson wrote:

abramson wrote:I will try find the 16 bit data and make a good normal map with Fridger's tools one of these days.

Besides, browsing Ciclops for the recent flyby of Enceladus, I found they released a new map of the little moon, much better than previous ones.

I made both:

• Moon Normal Map based on Kaguya elevation data.
• Enceladus textures based on Ciclops 2009-10-30 map.

Enjoy.
Guillermo

Abramson,

I am amazed at the collection of maps you have put together using Celestia. You all are talking about discrepancies in the readings from the poles? How exactly do you put these maps together, you seem like one of the more advanced users on the site and any advice on getting started would be greatly appreciated...

Hi starwalker,

they are using a professional (bur free) software and get the data directly from the scientific sources (oncee they are published). The software used is called ISIS and very capable. Haven't used it though, but if you search a bit for the term here on the forum or in the Net you will get directions on how to use it and what it all can do.

Regards,

Guckytos