Celestia Forums

Hi all,

Grant had spotted the large update of the USGS location labels for the Moon from 1857 ==> 8953 (!) and asked me to implement my importance weights into these new data.

This avoids overcrowded labels at any zoom level!

OK, this was easy to do and here is an illustration of the result



The trick is of course that for larger distance only the biggest locations are labelled...





My detailed, commented derivation of the importance weights is to be found in my Maple worksheet (~2.5MB, PDF format):

http://www.shatters.net/~t00fri/images/moon_weights.pdf

The striking feature is the almost perfect Normal distribution (Gaussian) of the log(size) of the craters around an average crater size of ~15.8 km:



Once more, this is a Celestia related application of (PERL) scripts, hey ElChristou
Bye Fridger

whoa nelly, what's that moon map? That looks much more detailed than the one I have.

Malenfant wrote:whoa nelly, what's that moon map? That looks much more detailed than the one I have.

I made it long ago. It's 8k.
But that's not the point of this thread

Bye Fridger

t00fri wrote:

Malenfant wrote:whoa nelly, what's that moon map? That looks much more detailed than the one I have.

I made it long ago. It's 8k.
But that's not the point of this thread

Bye Fridger

I know. But I still want to get hold of it - is it at your texture foundry?

t00fri wrote:....Once more, this is a Celestia related application of (PERL) scripts, hey ElChristou
Bye Fridger

RRRrrrr!!
Nice work and another tx for it.

Bye.

Very cool Fridger!! However, you are destroying my math student's beliefs that math is not used in the real world and especially not for leisurely endeavours... Histograms, distributions, log fuctions used to make linear equations. Indeed man, have you lost your mind.

buggs_moran wrote:...
Histograms, distributions, log fuctions used to make linear equations.

That I didn't understand...(there are no linear equations involved in the statistical part)

Indeed man, have you lost your mind.

That I did understand

Bye Fridger

t00fri wrote:The striking feature is the almost perfect Normal distribution (Gaussian) of the log(size) of the craters around an average crater size of ~15.8 km

It comes from the depths of my mind that a process of random breakage or fragmentation produces a lognormal distribution of fragment sizes. This seems to apply both to artificial processes (processing of ores) and natural ones (asteroids). From the distribution of asteroid sizes there seems to follow a similar one for craters. If I am not mistaken, the original model is due to Kolmogorov.

Cheers,

Guillermo

t00fri wrote:

buggs_moran wrote:...
Histograms, distributions, log fuctions used to make linear equations.

That I didn't understand...(there are no linear equations involved in the statistical part)

Bye Fridger

My bad Fridger. I went back and reread your worksheet. I had only given it a cursory glance last night (bad habits). I should know better. I see that the linear function of importance v. distance has nothing to do with the statistical ditribution...

Here is some further fun stuff related to the Moon.

I managed to FINALLY locate some true topographical
elevation data of the Moon with reasonably high
resolution from USGS. They are not so widely known since
they are in RAW grayscale format, both in 8bit and even in
16bit, such that a noise-less normal map can be made as
well (using Chris' nm16 code).



So I made a true 2k bump map file for the moon by
combining Celementine topography data (0.25x0.25 degree
resolution) with higher resolution elevation data for the
north and south pole regions. After eliminating many
artifacts, the result gives a qualitatively new perspective of
the Moon, based on my 8k main Moon texture.

Here is a taste of it:





Bye Fridger

Both of them are very nice,but when they will be available to download?

danielj wrote:Both of them are very nice,but when they will be available to download?

When I am entirely satisfied with them

Bye Fridger

Very nice indeed!!!
Lately I was thinking the Moon maps I'm using are really not fantastics...
I think I have found something better!!

Stunning work Fridger,

I'm sure I'll find the names to a lot more craters I see after I look through my telescope at night, using this package.