On Sun, 09 Aug 1998 06:49:59 -0500, Dan Connelly <djc### [at] flashnet>
wrote:

>Bret Slivka wrote:
>> 
>> Hello group.
>> 
>> I'm working on a 3d model of the planet Earth. I am trying to figure out
>> how to take this elevation map, turn it into a heightfield and somehow
>> "wrap" this heightfield around a sphere. but i'm a little stumped, so I
>> thought I'd tap into the vast knowledge of this collective for guidance.
>
>Features on the surface are under 10 km.  Yet the equator-to-
>pole distance is 10 Mm --- 1000 to one.  Therefore for any
>real purpose the Earth is smooth -- use textures
>instead if you want anything approaching realism.
>
Erm...how about using the image as a bump map?
Cheers,

Cliff Bowman
Why not pay my 3D Dr Who site a visit at
http://www.geocities.com/Area51/Dimension/7855/
PS change ".duffnet" to ".net" if replying via e-mail

Post a reply to this message

Jerry Anning wrote:

> Bret Slivka wrote:
>
> > I'm working on a 3d model of the planet Earth. I am trying to figure out
> > how to take this elevation map, turn it into a heightfield and somehow
> > "wrap" this heightfield around a sphere. but i'm a little stumped
>



> Incidentally, if your elevation map is from a freely available source, I
> would like to see a link.  I have been looking for such a map for my own
> experiments along these lines.
>
> Jerry Anning
> cle### [at] dholcom

---  See my post at povray.binaries.images.

I just posted two images.

One to be used as a grey scale height_field map.

The second is a full color overlay scaled the same
for image mapping over the first..

I believe both were generated taking into account
the distortion problem associated with mapping
onto a sphere and have been corrected accordingly.

Respectfully

K.Tyler

Post a reply to this message

If you want Bret, email me the elevation map.  I can convert it into a mesh
if you want (although the resulting file would have to be in dxf and it
could be very big, at least 2 Mb, to even come close to acheiving the detail
you're looking at).  All the same, I'll pop it into MAX and use the map as a
displacer on a geosphere.

--
Lance Birch
http://come.to/the.zone
Remove the smiley to e-mail.

Post a reply to this message

Bret Slivka wrote:

> Hello group.
>
> I'm working on a 3d model of the planet Earth. I am trying to figure out
> how to take this elevation map, turn it into a heightfield and somehow
> "wrap" this heightfield around a sphere. but i'm a little stumped, so I
> thought I'd tap into the vast knowledge of this collective for guidance.
> I humbly ask for your opinion on this matter.

Say.. I see this kind of stuff all the time...

Where CAN you get nice elevation maps, that are firendly for POV to use?
There are tons of random map generators, and nice custom map generators like
leveller, but I want the real thing! Most maps like this are in some format
ugly for POV to use.. Any ideas?

Simon
http://home.istar.ca/~sdevet

Post a reply to this message

Simon de Vet wrote:
> 
> Where CAN you get nice elevation maps, that are firendly for POV to use?
> There are tons of random map generators, and nice custom map generators like
> leveller, but I want the real thing! Most maps like this are in some format
> ugly for POV to use.. Any ideas?

I can't help you with POV-format maps, but for those who don't mind
doing their own conversion, you can find complete one-kilometre
resolution topographic data for the entire land surface of the Earth at
http://edcwww.cr.usgs.gov/landdaac/gtopo30/gtopo30.html .

-- 
Ross Smith ..................................... Wellington, New Zealand
<mailto:r-s### [at] ihugconz> ........ <http://crash.ihug.co.nz/~r-smith/>
   "Remember when we told you there was no future? Well, this is it."
                                                         -- Blank Reg

Post a reply to this message

Ross Smith wrote:
>  
> I can't help you with POV-format maps, but for those who don't mind
> doing their own conversion, you can find complete one-kilometre
> resolution topographic data for the entire land surface of the Earth at
> http://edcwww.cr.usgs.gov/landdaac/gtopo30/gtopo30.html .

Many utilities exist to do the conversion.  Leveller is probably
the best, as it includes a nice open-GL preview with fly-through
and supports explicit POV-Ray export.

Leveller: 
http://www3.sympatico.ca/tapio.vocadlo/leveller/

Dan

-- 
http://www.flash.net/~djconnel/

Post a reply to this message

Dan Connelly <djc### [at] flashnet> writes:

> Ross Smith wrote:
> >  
> > I can't help you with POV-format maps, but for those who don't mind
> > doing their own conversion, you can find complete one-kilometre
> > resolution topographic data for the entire land surface of the Earth at
> > http://edcwww.cr.usgs.gov/landdaac/gtopo30/gtopo30.html .
> 
> Many utilities exist to do the conversion.  Leveller is probably
> the best, as it includes a nice open-GL preview with fly-through
> and supports explicit POV-Ray export.

No, actually, Leveller isn't the best, as it's windows only. Not to
denigrate the author, but no program designed for use with POVray can
honestly claim the title 'the best' unless it runs on at *least* a
significant subset of the systems POVray does.
Leveller seems nice, and I'd like to see an X version of it, but until
there is one, 'the best' would have to be one of the command line
converters that will run on either unix or windows.

Shalon Wood

-- 
People who do stupid things with hazardous materials often die.
--Jim Davidson on alt.folklore.urban

Post a reply to this message

Shalon Wood wrote:

> No, actually, Leveller isn't the best, as it's windows only. Not to
> denigrate the author, but no program designed for use with POVray can
> honestly claim the title 'the best' unless it runs on at *least* a
> significant subset of the systems POVray does.
> Leveller seems nice, and I'd like to see an X version of it, but until
> there is one, 'the best' would have to be one of the command line
> converters that will run on either unix or windows.

I stand corrected -- I should have said the "best on W95".

Command line systems are not the best for Windows, where execution requires
opening a shell and dealing with the terrible W95 implementation of the
command line interface.  And GUI based packages often impede rather than
assist usage on UNIX, where command-line shells are highly developed
and quite convenient.  So there is no single "best" code for all
systems.

But to return to the original question -- many converters exist.
See, for example, dem2pov by John Beale:
http://shell3.ba.best.com/~beale/gforge/


Dan


-- 
http://www.flash.net/~djconnel/

Post a reply to this message

I know Dan and K. Tyler have been following, but if you haven't been
following the binaries.images group, I've gotten an initial
implementation of cylindrical and spherical mapping done.  Cylindrical
is pretty clean, the spherical works, but isn't very refined.  

Steve Lavedas

Bret Slivka wrote:
> 
> Hello group.
> 
> I'm working on a 3d model of the planet Earth. I am trying to figure out
> how to take this elevation map, turn it into a heightfield and somehow
> "wrap" this heightfield around a sphere. but i'm a little stumped, so I
> thought I'd tap into the vast knowledge of this collective for guidance.
> I humbly ask for your opinion on this matter.
> 
> Many thanks in advance,
> Bret

Post a reply to this message

Dan Connelly wrote:
> But to return to the original question -- many converters
> exist.
> See, for example, dem2pov by John Beale:
> http://shell3.ba.best.com/~beale/gforge/

Only sad that this converter doesn't work with this DEM format...but I
haven't found one yet too...so any hints welcome...

 See ya
   Udo

Post a reply to this message