Celestia Forums

Hi all,

I build a 32k night lights virtual texture. See my shots and tell me if it makes sence to have a night light map in 32k. I have no performance problems with my Duron900/GF3 64mb/512mb ram. By removing all unnecessary tiles I could reduce the number of tiles from 2730 to 1097.
( My old computer needs only one hour to build the level5/32k/1,5GByte inclusive DDS compession.)

Ok now the shots:


Philadelphia / New York


Portugal / Spain


Japan

You have sure noticed that my colors a bit different from that what you know as night lights. Please have a look at some real pictures .

And the best is I found my home towm .

Bye Jens

Jens

See my shots and tell me if it makes sence to have a night light map in 32k.

Yes please, it makes a lot of sense to me!

Would your texture also include aurora ?

regards
TERRIER

TERRIER wrote:Would your texture also include aurora ?TERRIER

No it has no aurora.

Bye Jens

it looks ok, but in my opinion they dont look like night lights...
but i want to try it, so when will it be available?

Hi all,

Have a look at a real pictiure. http://earthobservatory.nasa.gov/Newsro ... g_id=11278

I have my night lights now uploaded. See on my web page.

Bye Jens

Coud it be sodium vapor lights that make the night lights orange?

Brendan

jim wrote:Hi all,

Have a look at a real pictiure. http://earthobservatory.nasa.gov/Newsro ... g_id=11278

Hi Jens,

Yes, this is a "real" picture, but one taken with a hand-held electronic camera through the ISS windows ("...from the International Space Station with the handheld eclectronic still camera..."). Most, if not all "night" photos taken with automatic exposure hand-held cameras make lights appear to be orangish.

However, if you take a look at satellite photographs of the Earth's night lights, you will see the difference...



http://svs.gsfc.nasa.gov/vis/a000000/a002200/a002276/index.html



http://www.gsfc.nasa.gov/topstory/2003/0815citylights.html





http://www.nasm.si.edu/galleries/lae/html/orb_land_4.htm

Hope this helps,

-Don G.

Brendan wrote:Coud it be sodium vapor lights that make the night lights orange?

Hi Brendan,

At very low altitudes (ie. aircraft on approach to a city), the difference in illumination chemical types may be noticable. But, I don't think this would be the case for higher altitudes -- though I might be wrong.

-Don G.

Hi Don,

Thanks for this pictures. But I think that this satelite photos are far away from real (natural) colors. I found this statement about the satelites "The DMSP-OLS has a unique capability to detect low levels of visible-near infrared (VNIR) radiance at night."

My sample link is not the only night light picture I have seen. Photos from Londen, Paris, lights along the Nil and S?o Paulo shows similar colors. Sure my night lights are still to bright however this is a concession to the limit of our computers. Further lacks it at some details. Its a bit to blotty. Now the quality of the source map was not better.

Bye Jens

Hi Jens,

You can certainly use whatever color you like. The further up one goes, I would expect the color of city lights to become more color-distorted because of the atmosphere.

But before you make your final decision, please do like I did, and spend several hours searching the Internet for "night lights" along with whatever other keywords you would like. Then, when you find photos, read what the photo was taken with and how the picture was taken (ie. snapshot camera, single exposure, multiple exposure, timed exposure, film, CCD, etc., etc.).

Most, if not all, of the orangish light photos I found were taken by astronauts from the space stations or shuttle. These were taken with hand-held, single exposure, snapshot cameras -- some film and some CCD. There are no multiple exposure photos, because the shuttle and/or space station move too fast -- the pictures would not overlap correctly.

On the other hand, all of the white light photos I found were taken with a satellite. If you read about how these pictures were taken, you will find that most are multiple exposures over many days, weeks and even months. Then, the individual pictures are combined in a special process which brings out the light. The same thing can be done with snapshot cameras, but the camera and subject must both be stationary.

I'm sure Fridger could explain this in more detail since he is an optics and telescope making amateur. It's all about gathering light to the highest possible extent, which satellites and multiple exposure scene shots do quite nicely. Single shot, snapshot cameras do not do a good job at this.

-Don G.

I'd really like to see level 10 detail of some cities at night, and I've got to say the image of Buenos Aries in Jens' link looks pretty good. It would make those night side orbits a bit more interesting!

If it means using still camera images to get the best results to achieve this and having similar yellowish colours for the lesser resolution levels so the transition between levels is not noticeable when you zoom in, then I'm happy with it! I don't think it would be a bad idea just to call the entire vitual texture 'Still Camera night lights'.

Is it possible to run both a 'satellite' night light texture and a 'still camera' night texture both with the correct effect and have one as an alternate texture? In which case we have the best of both worlds.

Jens
It'd be nice to see a level 10 experiment with a city if possible? to see how it would look when zooming in from level 0. Maybe Buenos Aries ? - I reckon I can think of someone who would be quite happy to see this!

regards
TERRIER

I'll answer my own question here!

Is it possible to run both a 'satellite' night light texture and a 'still camera' night texture both with the correct effect and have one as an alternate texture? In which case we have the best of both worlds.

Yes you can. I'm running Don Edwards lights and aurora texture with my standard Earth texture and Jens new nightlights with my alternate 32k blue marble texture.

Here's my latest ssc Earth texture settings in solarsys using Jens newly available normalmap and specularmap VTs;



and my complete settings in BlueMarble DDS.ssc;


And it looks as if everything is working fine.

TERRIER: where you thinking about me?
Sure I will love to see the night lights from Buenos Aires in level10. On my holydays I went to Buenos Aires in plane, and i arrived ad night. It was an amazing view! there where withe, yellow and orange lights. Very beautifull. I am hoping to see something like that in Celestia.
It will be also good to see level10 night lights from other important cities in the world. I think that we can start from capitals: Buenos Aires, Santiago de Chile, Montevideo, La Paz, Brasilia, Mexico DF, Washington DC, Paris, Berlin... well, you know what I am talking about.
What do you think? Is it doable?

Because night lights, like normal planet surfaces, are affected by the atmosphere you're viewing through, shouldn't there be some kind of "haze" for the dark side of a planet too...?

Just an idea!

El Pelado

Ho Ho! Yep, I can't think of anyone else from Argentina on the forum, but maybe I'm wrong?

At the current time with version 1.3.1p11 I guess that going to level 10 resolution for nightlights is the ultimate direction for this particular feature. It would be great to see a few major cities / conurbations at this level of detail.

It'd also be nice to watch a city turn from night to day or vice versa!

regards
TERRIER

TERRIER...sync orbit. Position yourself above, say...I don't know...Florida at a low altitude and up the speed...great fun!....Even better from the shuttle!

Regards...bh. (not logged in again!).

there is a problem with this virtual texture: have anybody tryed to see the KSC in level10 texture and the nightlights virtual textures? it looks very bad...

Yes, it looks as if there are strange luminous banks of fog coming in from the sea.

Is this because the alignment is out, or simply because a level 5 texture is being mixed with a much greater resolution level 10 texture?

I don't think it is being totally fair, expecting the level 5 and the higher resolution tiles up to level 10, to match up!

Hi all,

ElPelado wrote:there is a problem with this virtual texture: have anybody tryed to see the KSC in level10 texture and the nightlights virtual textures? it looks very bad...

Here is a little bug fix for this problem. Add for all missed levels empty level folder to speculare VT and all works fine. This is also a general tip by problems with virtual textures.

TERRIER wrote:Jens
It'd be nice to see a level 10 experiment with a city if possible? to see how it would look when zooming in from level 0. Maybe Buenos Aries ? - I reckon I can think of someone who would be quite happy to see this!

Sorry Terrier, I have at the moment no plans to do such work.
But I plan to write a post about my virtual texture tools and scripts and how to use them. Maybe you can build than you own addons .

Bye Jens

So how is this coming? I can't wait to download it!