Apologies if this has been posted already.

NASA has released the "next generation" of their Blue Marble image maps of
the earth: http://earthobservatory.nasa.gov/Newsroom/BlueMarble/

The images are higher quality that the previous versions, cover topography,
bathymetry and the cloudless surface (one for each month of the year).

Resolutions are 5400 by 2700 (8km per pixel) and 21600 by 10800 (2km per
pixel) and, as usual, are free.

Very nice. :)

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"Alan Holding" <nomail@nomail> schrieb im Newsbeitrag 
news:web.434f5bb0b8731679e7014cf00@news.povray.org...
> Apologies if this has been posted already.
>
> NASA has released the "next generation" of their Blue Marble image maps of
> the earth: http://earthobservatory.nasa.gov/Newsroom/BlueMarble/
>
> The images are higher quality that the previous versions, cover 
> topography,
> bathymetry and the cloudless surface (one for each month of the year).
>
> Resolutions are 5400 by 2700 (8km per pixel) and 21600 by 10800 (2km per
> pixel) and, as usual, are free.
>
> Very nice. :)
>
>

Thank you for the nice news!
Now we're able to do animations that show the yearly cycle of the seasons. 
Let's see who is the first one who does it :)

Thies

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Thies Heidecke wrote:
> 
> Thank you for the nice news!
> Now we're able to do animations that show the yearly cycle of the seasons. 
> Let's see who is the first one who does it :)

Actually for this you would need shorter intervals - half a second of 
animation for a whole year is not exactly very useful...

The processing used for generating these looks quite impressive, i first 
wondered how they managed to generate a more or less cloud free image 
from only a month of data - the usual 32day composites contain 
significant cloud cover esp. in tropical regions.  You can find details 
on this and other processing aspects on:

http://snowy.arsc.alaska.edu/nasa/bmng/bmng.pdf

BTW an early test render (using the 2km variant) can be found on:

http://www.imagico.de/files/bmng1.jpg

(physically impossible BTW - notice the lighting combined with the 
january image...)

Christoph

-- 
POV-Ray tutorials, include files, Landscape of the week:
http://www.imagico.de/ (Last updated 07 Oct. 2005)
MegaPOV with mechanics simulation: http://megapov.inetart.net/

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Christoph Hormann wrote:

> BTW an early test render (using the 2km variant) can be found on:
> 
> http://www.imagico.de/files/bmng1.jpg
> 
> (physically impossible BTW - notice the lighting combined with the
> january image...)

Are you talking about the fact that the Sun shouldn't be above the
equator, or something else?

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> Actually for this you would need shorter intervals - half a second of
> animation for a whole year is not exactly very useful...

Well, you could interpolate between the images creating in total
360 images. Using a morphing program or something.

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Christoph Hormann wrote:

> 
> BTW an early test render (using the 2km variant) can be found on:
> 
> http://www.imagico.de/files/bmng1.jpg
> 

Christoph,

I've found your gallery of planet renderings quite interesting and useful.

I building up a scene showing the early stage of re-entry of John
Glenn's "Friendship 7" Mercury spacecraft. I've been working on modeling
the earth as it would be seen from about 90 miles (145 km) altitude,
probably somewhere over Texas.  The 8 km/pixel BlueMarble map is
obviously too coarse, and the 2 km/pixel map is two big to render in my
machine (3/4 GiB RAM).

You have some very nice renderings which seem to be a a fairly low
altitude, but I can't seem to find a description on your web site of how
you did it (or just what the altitude is).

Any tips?  I've thought of trying to slice up the whole earth image
somehow, is this what you did?  My thought is to process the image with
the convert tool from ImageMagick.  If you are doing a "close-up" like
this do you switch from a spherical to a planar projection on the image
map or do you use some other tricks?

Any advices would be welcome.

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Rick DeNatale wrote:
> 
> You have some very nice renderings which seem to be a a fairly low
> altitude, but I can't seem to find a description on your web site of how
> you did it (or just what the altitude is).

Well - the technique is outlined on:

http://www.imagico.de/pov/planets.html

When you use an isosurface for the geometry you are completely free to 
define the height function - you can combine a low detail basis with a 
higher detail region.  To define the areas the boxed pattern is well 
suited (for faster results i also recently used an object pattern when 
the transit region is not visible).  Mapping this to the sphere can be 
done using mapping warps or f_th/f_ph functions.

Most renders on http://www.imagico.de/pov/earth.html are from an 
altitude of about 200-500km.  The ones on 
http://www.imagico.de/pov/earth2.html are about 50-150km.

> Any tips?  I've thought of trying to slice up the whole earth image
> somehow, is this what you did?  My thought is to process the image with
> the convert tool from ImageMagick.

To extract an area from a very large image you need a tool that is able 
to do this without loading the whole image into memory.  The GDAL 
library can do this (specifically the gdal_translate program):

http://www.gdal.org/

Christoph

-- 
POV-Ray tutorials, include files, Landscape of the week:
http://www.imagico.de/ (Last updated 07 Oct. 2005)
MegaPOV with mechanics simulation: http://megapov.inetart.net/

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Rick DeNatale wrote:
> The 8 km/pixel BlueMarble map is
> obviously too coarse, and the 2 km/pixel map is two big to render in my
> machine (3/4 GiB RAM).

I've managed to render the 2 km/pixel map on 512 MB RAM, haven't tried 
it lately 'cuz bogged down in just playing with positioning of various 
elements using the 8 km version to decide that it's ready for a 'final'
render pass.  I tried, but failed, to combine the two 1 km hemispheres 
into a 43200x21600 map, partly due to insufficient system resources, 
partly due to the fact that I don't have an image editing program that 
can handle that large of an image.  I need a special app that'll splice 
them without needing to load the entire file into memory first.

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------

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Tim Cook <z99### [at] bellsouthnet> wrote:

> partly due to the fact that I don't have an image editing program that
> can handle that large of an image.  I need a special app that'll splice
> them without needing to load the entire file into memory first.

The NetPBM programs (which are the basis of ImageMagick) may be able to what
you want, since they are designed to run in pipes. I'm pretty sure that
pnmcat can join .ppm files, line by line. The .ppm format is very simple,
and these conversion & transformation utilities have been around for well
over a decade.

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