Celestia Forums

I discovered today that the Marsbump1k.jpg file is screwed up. I
think it's out of phase for the mars8k.dds file and vertically mirrored.

In any case, it doesn't at all match up correctly - you can really see
it by orbiting over mars, toggle ctrl-p on and off, and you'll see that the
great canyon's bump texture is on the reverse side of the planet.

Anybody else ever notice this.

I didn't try redmars8k.dds - is it the same?

Vic

Actually, the redmars dds seems to match the 1k bump ok. But that
other mars dds definitely doesn't match.

Vic

There are 2 distincly diferent version of the Mars textures out there. One has the tharsis area and olympus mons sittting toward the left side of the texture when viewed in a normal image viewing program. The other version available and the one that BlueMars and GreenMars are based on, the same features are one the right side of the texture toward the middle.
Here are examples.


You must use the right bumpmap that corisponse to the texture you are using or the results as you can already tell will be quite bad. This is also the case for the cloud map that was made for the real style Mars. If you use it with the wrong texture the clouds won't hover over the mountains and valleys but will be in the middle of nowhere. Lets not even get into the discusion over the color diferences. Most feel the top is more acurate while I prefer the lower one. I feel its closer to what the real color is. Maybe it needs just to be a little reder. Just a few things for you to chew on.

howdy!
i noticed this problem a while ago, and fixed the map myself over many hours of trial-and -error. I can post the bumpmap, but i have no site, so if anyone can point me in the direction to get it up and out there, please let me know. i am using this bumpmap with the 16k mars - it takes forever to load the two, but i feel VERY worth it...[/code]

16k Mars map - Where's that hiding?

Vic

You needn't have done all that work. There are matching bumpmaps for both if you simply look for them. You can find the 16k texture in dds format at Fridger's Texture Foundry site at http://www.celestiaproject.net/~t00fri/texfoundry.html
You will find them in the downloads area by memory size.

You're really trying to make Grant work, aren't you?

Don't forget that if you're going to use a bump map and surface texture with 0 at the edge, then you should specify a rotation origin in solarsys.ssc which is different from what is specified when you use maps with 0 in the middle. The sun should be over Olympus Mons at Noon, not Midnight!

I just now took the time to check.

The maps of Mars and solarsys.ssc as shipped with Celestia do not agree with one another.

The maps shipped with Celestia have 0 degrees at the right edge: Olympus Mons is in the right half of the image and Syrtis Major (the large dark feature) is in the left half.

solarsys.ssc follows the IAU standard and assumes the use of Martian maps with 0 degrees in the center. Olympus Mons should be in the left half of the image and Syrtis Major in the right half.

See, for example, http://www.giss.nasa.gov/data/mars/time/
which has Airy in the center. (The center of the crater Airy is defined to be 0 degrees Longitude.)

Another check is to look at Celestia's image of Mars and compare it with observations made at one of the oppositions. When it's supposed to be noon there, with Syrtis Major in the center of the viewable side of the planet, Celestia shows Syrtis Major on the dark side. E.g, for the 2001 opposition see http://mars.jpl.nasa.gov/mgs/msss/camera/images/opposition_6_2001/ although they're simulations, not photographs taken during opposition.

And here I had been assuming Celestia's maps were right. Now I've gotta redo a lot of things, including the RGB mars maps.

sigh.

Don. Edwards wrote:You needn't have done all that work. There are matching bumpmaps for both if you simply look for them. You can find the 16k texture in dds format at Fridger's Texture Foundry site at http://www.celestiaproject.net/~t00fri/texfoundry.html

I've been to this site many times, and I just went there and there's
no 16k textures anywhere on his site - so I don't know what 16k
textures you're referring to there.

Vic

I noticed that last year ,and i thought everyone new it

Grant Hutchison has determined tht the rotational description for Mars in solarsys.ssc is wrong, not the maps. He's included revised values in the thread where he's been discussing the similar problems affecting many of the natural satellites.

See http://63.224.48.65/forum/viewtopic.php?t=1331

Don Wrote:
You needn't have done all that work. There are matching bumpmaps for both if you simply look for them.

Well Don, sorry that some of us do workarounds and some of us do searches. I wanted a problem fixed, and wasnt a regular visitor to this site. I had checked the site you mentioned, and many others, without finding the updated bimpmap. So I took the time to make one. This is supposed to be fun and educational, and if someone takes the time to do their own mods, it shouldn't be lumped into the category of "wasting time"...

Vicware,
Sorry about that. I brain farted. Its on the damirof server. Slow but atainable over time. You can find a link to the server in the first thread of this area under Large DDS. If you can't see see th files you can always go through the directories to find it. Or you can go to Space-Graphics.Com and download there Mars textures. But be warned that you will ahve to resize them up or down to your needs.

ou8poop2,
What I ment was that most of the sites that have textures also post the bumpmap along side of it as a seperate download. I don't know what site you got your texture from but the sites that I regulary visit have the bump as well as the texture. I didn't mean to sound like I was saying it was a complete waste of time to make your own. Its just a simple fact that if someone wants something bad enough it can be found and ususaly without an extensive search. But by all means keep working on what you feel is fun. I do it as well. Simply check my thread of GreenMars. You can't get anymore texture manipulating than that.

Does this mean that the view of the surface of Mars from Earth/anywhere isn't accurate?

Anonymous wrote:Does this mean that the view of the surface of Mars from Earth/anywhere isn't accurate?

Yes, that's what it means: the image of Mars is effectively rotated 180 degrees from what it should be.

Follow the link above to the thread where Grant has determined better rotational parameters that you can put into solarsys.ssc