Limit of knowledge

[jogad]

Hello,

Two little details:

The first was yet in Celestia 1.5

lokPluto.jpg

If we right-click on Pluto or Charon and choose "Limit of knowledge" the surface doesn't change!
I know that this is very easy to solve. I think of the many users of Celestia who are not members of the forum and don't have to know why.


The second one is specific to the newest versions of Celestia 1.6
For Mercury there is no more "limit of knowledge" texture but the normal texture looks like that:

lokMercure.jpg

Is it really the normal texture? For sure is is an improvement in terms of accuracy but it is not very pretty.

[ElChristou]

...The second one is specific to the newest versions of Celestia 1.6
For Mercury there is no more "limit of knowledge" texture but the normal texture looks like that:...

Is it really the normal texture? For sure is is an improvement in terms of accuracy but it is not very pretty.

Yep... this is a map by an outsider and it don't match the quality criterion we are used to with the saturnian moons... I agree it's a bit weird for Celestia to have such map...

[t00fri]

My God...

and it would be so easy to render this texture BOTH accurate AND nice!

Fridger

[selden]

To put it more politely (glares at Fridger)
the decision has been made to eliminate Limit-of-Knowledge overlays and provide only planetary surface texture images which are correct. Only one planet and one moon are affected: Mercury and Mimas.
Mimas already has a complete map

(For the time being, we'll ignore the fake asteroid.jpg which is applied to bodies which do not have known surfaces.)

Mercury's map is a merge of recent Messenger images with older Mariner images,
Hopefully, additional Messenger images will be added to the map when they become available, some time after the next flyby, which will be in September.

If you want a complete, but fake, map of Mercury, surface textures are available on the MotherLode at http://www.celestiamotherlode.net/catalog/mercury.php

It was an oversight that the Pluto LoK images did not get deleted -- they probably should never have been included.

[t00fri]

To put it more politely (glares at Fridger)
the decision has been made to eliminate Limit-of-Knowledge overlays and provide only planetary surface texture images which are correct. Only one planet and one moon are affected: Mercury and Mimas.
Mimas already has a complete map

(For the time being, we'll ignore the fake asteroid.jpg which is applied to bodies which do not have known surfaces.)

Mercury's map is a merge of recent Messenger images with older Mariner images,
Hopefully, additional Messenger images will be added to the map when they become available, some time after the next flyby, which will be in September.

If you want a complete, but fake, map of Mercury, surface textures are available on the MotherLode at http://www.celestiamotherlode.net/catalog/mercury.php

It was an oversight that the Pluto LoK images did not get deleted -- they probably should never have been included.

Selden,

I am perfectly aware of what is up with Mercury, since I am working since some time on an ambitious Mercury texture (for Celestia.Sci) that uses ALL the available messenger data via ISIS3 etc.

It is just a matter of mastering certain image manipulation techniques to render a scientific texture also visually pleasing. That's what we mean. Certainly NOT to fill the voids with crater patches from the Moon

Fridger

[selden]

Fridger,

My explanation was not for you, but rather for Jogad. Sorry I didn't make that obvious.

Unfortunately I was also mistaken about how many bodies are affected.
If Celestia is going to be strict about no longer including artistic maps of unknown regions,
then the SSC entries for the following bodies also have to be corrected:

Io
Europa
Ganymede
Callisto
Epimetheus
Hyperion
Miranda
Ariel
Umbriel
Titania
Oberon
Triton
Pluto
Charon

[t00fri]

It is perfectly possible to render lok type textures in a manner that is NOT offending for the eye.

Rule number 1):
Apply a strong Gaussian smearing to the data in question and determine this way the "average color" of the image. Use that color for the LOK regions without data. This way one still can see where data are lacking, yet it is by far not such a visual shock as Mercury above..

Rule number 2): In case of composite textures consisting of many mosaic patches, smoothness of brightness and contrast across the many artificial mosaic boundaries is a physically correct and hence very sensible constraint. Many "scientific" mosaic maps ignore this fact badly... To remedy this situation one has to apply layer techniques, using gradient masks to match the brightness appropriately... It is tedious, but perfectly possible.

etc...

Fridger

[chris]

There are three obvious options:

1. Revert to the old pre-MESSENGER texture
2. Keep Steve Albers' map
3. Create a new map with better fill color in the blank areas and improved blending

Option 1 seems like a poor choice--we'd miss out on a lot of beautiful detail from MESSENGER. Option 3 is ideal, but we need a qualified volunteer to produce a new Mercury map.

--Chris

[ElChristou]

...Option 1 seems like a poor choice--we'd miss out on a lot of beautiful detail from MESSENGER. Option 3 is ideal, but we need a qualified volunteer to produce a new Mercury map.

Yep... but who can be enough qualified... that's the question!

[John Van Vliet]

--- edit ---

[t00fri]

Certainly NOT to fill the voids with crater patches from the Moon

well that is what i did

I know that.

Fridger

[jogad]

Happy Easter to everybody

I took a glance at the revamped texture by toofri.
viewtopic.php?f=5&t=13671
Very impressive work.
Thank you very much Fridger . Despite of you, you are not only a scientist but also an artist.

BUT

the decision has been made to eliminate Limit-of-Knowledge overlays and provide only planetary surface texture images which are correct.
...
If you want a complete, but fake, map of Mercury, surface textures are available on the MotherLode

I regret the deliberate elimination of Limit-of-Knowledge overlays.
Actually this is the replacement of the normal textures by limit-of-knowlegde textures.

The normal textures provided a plausible image of a planet and a good first look at it for example to make acquaintance in a tour of the solar system.
I am not scandalized by the use of other textures to fill the gaps if the result is not inconsistent with known scientific data. My opinion is that imagination should not be banned from Celestia.

The limit-of-knowledge brings precision of what is actually known or not. This is a valuable scientific tool but not a representation of the surface.

For the global representation of the planet, the flat surface of the unknown part is not more realistic (and probably less) than imaginary craters.

Celestia is not ONLY a scientific data source but also a program for discovery and amazement in front of the Universe.

Removing the normal textures to keep only the limit-of-knowledge ones is a real loss and a restriction of the use of Celestia itself witch is now intended to a more specific public.

[selden]

I misunderstood ChrisL's intent. Sorry to mislead people.

He wanted to use a more accurate map of Mercury, so Celestia v1.6 RC0 includes Steve Albers' map of Mercury and no LoK for Mercury. Discussions here and on the Developers' mailing list have changed his mind about how to improve the map of Mercury, but I'm not sure what RC1 will include.

The use of artistic maps and LoK overlays for the moons mentioned above is unchanged from v1.5.1. Improved maps are included for several moons.

[BobHegwood]

I misunderstood ChrisL's intent. Sorry to mislead people.

He wanted to use a more accurate map of Mercury, so Celestia v1.6 RC0 includes Steve Albers' map of Mercury and no LoK for Mercury. Discussions here and on the Developers' mailing list have changed his mind about how to improve the map of Mercury, but I'm not sure what RC1 will include.

The use of artistic maps and LoK overlays for the moons mentioned above is unchanged from v1.5.1. Improved maps are included for several moons.

If I may the Selden...

Why is it that when I try to add a LOK map to the solarsys.ssc file for Mercury, the
program loses it's marbles?
By that I mean that if I press a 1 to go to Mercury, I get pointed to some star instead.
If I remove the LOK specifications from solarsys.ssc, then I have no problems.

Should I download an even later release now?
Sorry for the question, and thanks for the answer.

[selden]

Bob,

Since you edited solarsys.ssc, I have to suspect that you made a typo somewhere.
Most likely, you put the AltSurface inside the definition of Mercury.
It should be a separate entry.

It'd be a lot safer to put it in its own file in extras for now.

I don't think any updates for Mercury have been made since RC0 was created.

[BobHegwood]

Okay thanks again, Selden. I'll try it a bit more carefully this time.

[BobHegwood]

Just wanted to thank you again, Selden. My Mercury
LOK texture works beautifully now. Amazing what this program
can do when you treat it correctly.

Thanks very much to the Good Doctor too. Absolutely beautiful
(and real) LOK texture in use now.

[deantracer]

Hi to all...
I don't think there is limit of knowledge it was really good knowledge..
But guys i have limit of on this site...