Celestia Forums

Hello everybody,
I just discover celestia and i am very impressing by the "community" of celestia. Thank you to all to allow us having such beautiful addons !
I studied Mars with remote sensing and I'm interested in available textures but I have some difficulties to realigned them....
Does somebody know how to do this ???
Thank you for all,
Ariane mascret.

Ariane wrote:Hello everybody,
I just discover celestia and i am very impressing by the "community" of celestia. Thank you to all to allow us having such beautiful addons !
I studied Mars with remote sensing and I'm interested in available textures but I have some difficulties to realigned them....
Does somebody know how to do this ???
Thank you for all,
Ariane mascret.

Hi Ariane,

why do you want to realign the textures? What do you precisely want to do? I could tell you a lot of things but I first need to know whether you are a beginner in image manipulation or an expert etc...

Bye Fridger

Hi Fridger,
I usually use geographical information system soft, so I always verify the georeferencing. And in Mars I saw that rivers or volcanos are not perfectly superimposed (I'm sorry for my bad english... I work to improve it ! ) So... i just want to know if it's possible to correct this easily???
I'm not really a beginner in image manipulation but in Celestia yes !
Thank you for the reply...
Ariane

Ariane wrote:Hi Fridger,
I usually use geographical information system soft, so I always verify the georeferencing. And in Mars I saw that rivers or volcanos are not perfectly superimposed (I'm sorry for my bad english... I work to improve it ! ) So... i just want to know if it's possible to correct this easily???
I'm not really a beginner in image manipulation but in Celestia yes !
Thank you for the reply...
Ariane

Hi Ariane,

I am still confused. What did you take as a reference for what you call imperfect alignment of rivers or vulcanos on Mars??

Or are you talking about an imperfect matching of the normal map texture features with those of the main surface texture?

I have created many super hires textures (up to w x h=32k x 16k !) of Mars but never observed anything like what you describe.

Bye Fridger

Hello Fridger,
oups... Sorry, I didn't know that you have created many texture...! I hope you don't think that I criticize easily... You have done such a fantastic work ! and I wish I can do the same ....!

I haven't Celestia on my computer here, so I will take some screen capture tonight in order to show you tomorrow. I think a picture will speak more better and clearly than me...Are you agree ?

bye, Ariane

i think what he means (by the way i am working on this same problem )
is that the mola data takes into account the Oblateness and MISS/USGS dose not
ie. mola is maped differently from miss and usgs , the miss map is maped to a perficet sphear

take a look at my mars the 16k,8k,... are remaped
a 32k and 64k( and maby 128k map) are in the works


this is a composit the color image is the mola data and the black and white on
top is miss 256

john Van Vliet wrote:i think what he means (by the way i am working on this same problem )
is that the mola data takes into account the Oblateness and MISS/USGS dose not
ie. mola is maped differently from miss and usgs , the miss map is maped to a perficet sphear

take a look at my mars the 16k,8k,... are remaped
a 32k and 64k( and maby 128k map) are in the works


this is a composit the color image is the mola data and the black and white on
top is miss 256

John,

your problem is of course well known to me. That is somewhat tedious, indeed. But Ariane's problem was trivial: I had a look at her BlueMars map. It did still use the old central meridian convention...

Bye Fridger

that old one , i had forgotten about it

ps an idia for the speed chalanged 56 & 26 k people
in doing a quote how about leaving out the image ( .png's do take a bit to loade )

Why not use version 2.1 of the mars digital image mosaic:

http://astrogeology.usgs.gov/Projects/MDIM21/

instead of MSSS. It matches mola data as close as can be. Although not the most beautiful map available( opposing shadows etc.), it is the most accurate and detailed global map i have found.

DBrady... wrote:Why not use version 2.1 of the mars digital image mosaic:

http://astrogeology.usgs.gov/Projects/MDIM21/

instead of MSSS. It matches mola data as close as can be. Although not the most beautiful map available( opposing shadows etc.), it is the most accurate and detailed global map i have found.

Right, now that I have a very fast ADSL line I want to put my hands on those data as soon as I'll find some time.

Bye Fridger

t00fri wrote:....It did still use the old central meridian convention...

How can I solve that one? I don't know very much of graphics. I'm sure that has been explained before. can you re-direct me?

To change the meridian of a surface texture map image, cut it in half, so that you have left and right square halves. Exchange those two halves, so that the new image has them swapped.

selden wrote:To change the meridian of a surface texture map image, cut it in half, so that you have left and right square halves. Exchange those two halves, so that the new image has them swapped.

Code: Select all

Original:

=========
| L | R 0
=========

Final:

=========
| R 0 L |
=========


Selden,

I am afraid that this is far from being the simplest way with GIMP or Photoshop. Actually, most of my conversation with Ariane went via many emails, where I also gave her detailed instructions.

In GIMP, one simply goes to Layer->Transform->Offset...
Enter into the offset dialog's x-slot: width/2 in pixels and make sure that "Wrap" is activated. So for a 4k texture, one enters 2048, etc.

In PS, the procedure is the same except, I think one finds the Offset dialog under Filters...

Bye Fridger

Fridger,

Of course, I don't use either GIMP or PhotoShop.
I was providing the generic method, which can be implemented using any graphics utility.