Celestia Forums

I am working on a good Ceres texture for a while. My effort is to produce an albedo color map (without shading, as close as possible to real color and brightness).

This is one try, the original texture is a 21k png (131MB!). I combined several textures published by NASA, still far from perfect.
https://drive.google.com/open?id=0B14NSu0PnA5xY20tc3V2cHV1cmc

Here is another try, just using one color texture by NASA, it is in much smaller resolution (the one I post is a jpg in full resolution):
https://drive.google.com/open?id=0B14NSu0PnA5xMkxEeHhDTjc0WlE

In both cases, I tried to remove the shadows by using the published DEM, but processed differently: http://www.planetary.org/multimedia/space-images/small-bodies/ceres-20150219-dem.html
But as far as I know it is from bevore orbit insertion and thus in very poor resolution. Are there any better global topography maps avaliable yet? Or a high incident angle texture?

you do know i have a 32bit cub file for that very OLD and very early Ceres dem
it is from pre orbital images taken on approach

the one emily posted is a 8 bit normalized copy

John Van Vliet wrote:you do know i have a 32bit cub file for that very OLD and very early Ceres dem
it is from pre orbital images taken on approach

Is it the one you posted a normalmap from on the Motherlode? Emelys version is closer to reality. Resolution would not be any different if it was pre-orbit. Also since the DEM is blurry, I can easily work around 8bit artifacts in the normalmap.

If it is a cub file I have no use for it since I have no idea how to read such a file. I am despairing over all the NASA images online in cub format!

Emelys version is closer to reality.

that image on the planetary society page is mine
converted from a vertex/face shape file into a per meter dem ( approx.)

and until the HAMO images are released to pds this is the only dem
or until one is posted on pds

Ok I thought you mean the one on the motherlode.

Dammit we need a better one. When to expect a pds release? How was it with Vesta?

Vesta has a very nice 3d mesh "vesta512.bds"
http://dawndata.igpp.ucla.edu/tw.jsp?section=geom ... els/GASKELL_CLAUDIA_2013_02_13
once converted to a isis3 cub it is a 587 meg heighrmap -- 48 pixels per degree


or a 450 meg mesh in blender

Yes I'm using a 22MB binary cmod in my installation. More resolution would be nice, but not necessary. Maybe as a normalmap. But again, I have no idea how to use this online data unless it is in an easily readable format, the best Vesta DEM I have is 4k normal you posted somewhere, it worked fairly good to produce an acceptable albedo map.

Seeing NASAs renderings I think they have at leat a somewhat better DEM of Ceres.

Steve Albers has done a great looking updated Ceres map in 8K

Here is the link: http://laps.noaa.gov/albers/sos/sos.html

Here is an image of the map:

fsgregs wrote:Steve Albers has done a great looking updated Ceres map in 8K

Yes I've seen that one. But lightning condistions in this texture are very inconsistent, and projection is a bit inacurrate. I prefer NASA's projection, like this one:
http://space.frieger.com/asteroids/data/dwarf/textures/Ceres/DLR2016/grayscale.jpg?size=max

When John Van Vliet releases his Ceres normal map, I can use this data to remove shading from the map, after a bit of procession I will get close to an albedo map. Hopefully NASA publishes a high-indicent-angle texture as they did with Mercury.

there is a large LAMO clear filter mosaic
--- preview ---
http://sbn.psi.edu/archive/dawn/fc/certified/DWNC ... CE_LAMO_G_00N_180E_EQU_CLR.JPG
and
http://sbn.psi.edu/archive/dawn/fc/certified/DWNC ... CE_LAMO_Q_43N_045E_LAM_CLR.JPG

the pds LAMO img map is 3.3 GIG
the older HAMO 21093X 10546 is 212 MiB

I guess the texture I linked is the HAMO mosaic then. The LAMO mosaic must be huge, much too large for my computer to handle... But it looks great from the browse previews

FarGetaNik wrote:much too large for my computer to handle

need some help with that? got an extra 8GB i wanna use on something.

nardo wrote:need some help with that? got an extra 8GB i wanna use on something.

Sure thanks well its not about disc space, but I can't possibly process such huge textures. It would be necessary to convert img to png and if downscaled to ~ 20k texture, I can handle it.

FarGetaNik wrote:its not about disc space

i meant ram. 16gb is making my life so much easier.

FarGetaNik wrote:It would be necessary to convert img to png and if downscaled to ~ 20k texture

i'm downloading it now, and it's quite the image. i'll see if my laptop can handle it.

working on the 3 gig image .Right now i am removing the low light shading near the poles


this is 45 to 90 north and is 22250 x 22250 pixels

nardo wrote:i meant ram. 16gb is making my life so much easier.

That's great for you. And that's exactly my problem.

John Van Vliet wrote:working on the 3 gig image .Right now i am removing the low light shading near the poles

Looks very promising. If the topography matches well, it should be possible to remove all the shading and produe an albedo map, necessary if rendering a normalmap in Celestia.

So I've found the DEM on USGS: http://astrogeology.usgs.gov/search/map/Ceres/Dawn/DLR/FramingCamera/Ceres_Dawn_FC_HAMO_DTM_DLR_Global_60ppd_Oct2016

But while trying to process it my computer slowed incredibly. Monotoring with task manager clearly showed my RAM to be exhausted and finally I got a bluescreen. maybe I broke something there

If you haven't already, you might consider configuring a large, fixed paging file instead of letting windows dynamically adjust its size. That can help improve performance when it runs out of RAM. The traditional rule-of-thumb for paging file sizes is 4X the size of the RAM.

get an account so you can resize and reformat with their online tool. that's how i used to do it.

or you can use a tiled version then glue the tiles back together...

selden wrote:If you haven't already, you might consider configuring a large, fixed paging file instead of letting windows dynamically adjust its size. That can help improve performance when it runs out of RAM. The traditional rule-of-thumb for paging file sizes is 4X the size of the RAM.

Hm thanks for the tip, didn't know about that. Well I don't want to complain too much, I just was kind of frustrated Today I tried out photoshop on my university's computers, and it worked well despite same RAM size. It might just come back to the unstable developer's version of Gimp I'm using right now to handle 16bit.

nardo wrote:get an account so you can resize and reformat with their online tool. that's how i used to do it.

or you can use a tiled version then glue the tiles back together...

That's possible on USGS? I'll search for it, maybe it will be easier to get the data I want (and not these huge .cub files). Thanks for the textures, this helps alot