Hi you all.

I am planning on rendering afly-by of some parts of the world ( with the
actual reliefs, seas and all).

I downloaded one so-called DEM files but did not manage to get anything
from it. As the file is 16Mb large,....%£!!?@@§/ ( censored) you can
understand my nervousness. All the DEM utilities fail to read it ( and
the file is not corrupted as it is in a normal .tgz format and I can see
its content).

The readme file says :
"The DEM is provided as 16-bit signed integer data in a simple binary
raster.
There are no header or trailer bytes imbedded in the image.  The data
are
stored in row major order (all the data for row 1, followed by all the
data
for row 2, etc.)." ----> I tried to read it as a Raw file, but it
doesn't work. Am I right ?

I tried with a smaller file but no more luck.


Does anyone know if I can find somewhere on the net files which have
already been converted for height_fields use( TGA, PNG,....)

Thanks

Fabien Hénon

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Hi!

Look for the following thread in povray.binaries.utilities:
Subject: Problem DEM2POV/DEM2TGA?
Date: Fri, 17 Apr 1998 18:56:57 +1000

I've posted there as response my DEMTOTGA conversion program and source
code. There are links to other conversion programs too.

Hope this helps.

Post a reply to this message

Fabien Hénon wrote:
> 
> Hi you all.
> 
> I downloaded one so-called DEM files but did not manage to get anything
> from it. As the file is 16Mb large,....%£!!?@@§/ ( censored) you can
> understand my nervousness. All the DEM utilities fail to read it ( and
> the file is not corrupted as it is in a normal .tgz format and I can see
> its content).
> 
On second thought, are you using DEM files? What do you mean by "normal
.tgz" format? Have you uncompressed and untar-ed it? When I worked with
DEM files, then height information file was 80 MB + there was number of
auxilary files. Seems like you haven't unpacked them...

Post a reply to this message

Well, I did untar and uncompressed the files and I got a number of files :
>W020n40.dem     56 Mb
>W020n40.dmw
>W020n40.hdr
>W020n40.prj
>W020n40.sch
>W020n40.src    28 Mb
>W020n40.stx

I give the size for the largest files only. The others are only a few bytes
large.

I read the readme file, but it does not say how to handle the files.


I have the feeling that the DEM file is not a proper one ( The DEM extension
is not correct here).

I downloaded the file from :
http://edcdaac.usgs.gov/gtopo30/gtopo30.html



Vahur Krouverk a écrit :

> Fabien Hénon wrote:
> >
> > Hi you all.
> >
> > I downloaded one so-called DEM files but did not manage to get anything
> > from it. As the file is 16Mb large,....%£!!?@@§/ ( censored) you can
> > understand my nervousness. All the DEM utilities fail to read it ( and
> > the file is not corrupted as it is in a normal .tgz format and I can see
> > its content).
> >
> On second thought, are you using DEM files? What do you mean by "normal
> .tgz" format? Have you uncompressed and untar-ed it? When I worked with
> DEM files, then height information file was 80 MB + there was number of
> auxilary files. Seems like you haven't unpacked them...

Post a reply to this message

Fabien Hénon wrote:
> 
> Well, I did untar and uncompressed the files and I got a number of files :
> >W020n40.dem     56 Mb
> >W020n40.dmw
> >W020n40.hdr
> >W020n40.prj
> >W020n40.sch
> >W020n40.src    28 Mb
> >W020n40.stx
> 
> I give the size for the largest files only. The others are only a few bytes
> large.
> 
> I read the readme file, but it does not say how to handle the files.
> 
> I have the feeling that the DEM file is not a proper one ( The DEM extension
> is not correct here).
> 
> I downloaded the file from :
> http://edcdaac.usgs.gov/gtopo30/gtopo30.html
> 

If my memory serves me correctly, then I've used files from same site
and the set of files seems to be OK. File size is probably OK too, my
memory failed here: whole package was probably >80 MB. Have you tried my
converter (see my previous post)?

Post a reply to this message

Vahur Krouverk wrote:

> If my memory serves me correctly, then I've used files from same site
> and the set of files seems to be OK. File size is probably OK too, my
> memory failed here: whole package was probably >80 MB. Have you tried my
> converter (see my previous post)?

I just downloaded a dem from that site and the two utilities I have for
conversion choked on them too. I then downloaded your utility and while
it was able to read the file and convert it to a .tga image there was
erroneous data in the resulting .tga the rendered it useless to me.
The dem I downloaded is of the Hawaiian Islands (w180n40.dem) which is
fairly well centered in the data. When converted to tga, with your
utility, there is a green colored stripe going directly through the
island chain (directly in the middle of the image) running left to
right. It takes up a sizable chunk of real estate

Any idea what may be causing that ?

-- 
Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message

Ken wrote:
> 
> The dem I downloaded is of the Hawaiian Islands (w180n40.dem) which is
> fairly well centered in the data. When converted to tga, with your
> utility, there is a green colored stripe going directly through the
> island chain (directly in the middle of the image) running left to
> right. It takes up a sizable chunk of real estate
> 
> Any idea what may be causing that ?
> 
As I wrote in the binaries, I had similar problems (some parts seemed to
be incorrect) and I don't know, whether this is problem in my converter
or data. I'll look at my source.

Post a reply to this message

Ken wrote:
> The dem I downloaded is of the Hawaiian Islands (w180n40.dem) which is
> fairly well centered in the data. When converted to tga, with your
> utility, there is a green colored stripe going directly through the
> island chain (directly in the middle of the image) running left to
> right. It takes up a sizable chunk of real estate
> 
> Any idea what may be causing that ?
> 
I d-l same file and got same result. As matter of fact, there is red and
green component in this stripe. I think that this is
compression-decompression problem, as it reaches from one high peak to
other. I try in on home computer (linux box) to see, if this helps.

Post a reply to this message

Check out the FAQ there, this type of DEM is not ASCII.
http://edcdaac.usgs.gov/gtopo30_faq.html

Bob

|
| I read the readme file, but it does not say how to handle the files.
|
|
| I have the feeling that the DEM file is not a proper one ( The DEM extension
| is not correct here).
|
| I downloaded the file from :
| http://edcdaac.usgs.gov/gtopo30/gtopo30.html
|

Post a reply to this message

So, is there a way I can convert this 'simple binary raster format' ? With
Photoshop 5 maybe.
I have to say that I have never heard of this file format.

If anyone knows if/how it can be converted. I tried to open it as a RAW  file with
different options, but all I get is a blurry image.


Thanks

Fabien Hénon


Bob Hughes a écrit :

> Check out the FAQ there, this type of DEM is not ASCII.
> http://edcdaac.usgs.gov/gtopo30_faq.html
>
> Bob
>
> |
> | I read the readme file, but it does not say how to handle the files.
> |
> |
> | I have the feeling that the DEM file is not a proper one ( The DEM extension
> | is not correct here).
> |
> | I downloaded the file from :
> | http://edcdaac.usgs.gov/gtopo30/gtopo30.html
> |

Post a reply to this message

No help maybe but here's URLs to the two programs mentioned there at the gtopo30
web page.
http://www.esri.com/software/arcview/index.html
http://www.esri.com/software/arcinfo/index.html

I think it just comes down to the change in data format.
See the section 5.0 here in the readme:
http://edcdaac.usgs.gov/gtopo30/README.html#h15

Bob

"Fabien Hénon" <ffj### [at] club-internetfr> wrote in message
news:38F77ED9.C7DC260C@club-internet.fr...
| So, is there a way I can convert this 'simple binary raster format' ? With
| Photoshop 5 maybe.
| I have to say that I have never heard of this file format.
|
| If anyone knows if/how it can be converted. I tried to open it as a RAW  file
with
| different options, but all I get is a blurry image.
|
|
| Thanks
|
| Fabien Hénon
|
|
| Bob Hughes a écrit :
|
| > Check out the FAQ there, this type of DEM is not ASCII.
| > http://edcdaac.usgs.gov/gtopo30_faq.html
| >
| > Bob
| >
| > |
| > | I read the readme file, but it does not say how to handle the files.
| > |
| > |
| > | I have the feeling that the DEM file is not a proper one ( The DEM
extension
| > | is not correct here).
| > |
| > | I downloaded the file from :
| > | http://edcdaac.usgs.gov/gtopo30/gtopo30.html
| > |
|

Post a reply to this message

OK,

I have to admit, that this was error in my code, after all. It was this
infamous and old trick: "opening-binary-files-in-text-mode", which from
time to time tortures those programmers who code in MS-DOS. Now it
should work OK, so virtual trip to Hawaii (and around the world) is
possible. I've uploaded new version to binaries.utilities. Note, that it
has different options now (e.g. scaling is not performed by default).

Post a reply to this message

Fabien Hénon wrote:
> 
> So, is there a way I can convert this 'simple binary raster format' ? With
> Photoshop 5 maybe.
> I have to say that I have never heard of this file format.
> 
> If anyone knows if/how it can be converted. I tried to open it as a RAW > file with
> different options, but all I get is a blurry image.
> 
Have you tried my coverter? I've uploaded new version to
binaries.utilities, which converts those files to POV-Ray .TGA
heightfield format.

Post a reply to this message

Vahur Krouverk wrote:
> 
> OK,
> 
> I have to admit, that this was error in my code, after all. It was this
> infamous and old trick: "opening-binary-files-in-text-mode", which from
> time to time tortures those programmers who code in MS-DOS. Now it
> should work OK, so virtual trip to Hawaii (and around the world) is
> possible. I've uploaded new version to binaries.utilities. Note, that it
> has different options now (e.g. scaling is not performed by default).

OK,

 I tried it on Hawaii again and (I really hate to tell you this) the
results were worse than with your original utility. Before I could
at least see the islands now they are skewed all over the place. In
the areas were there is no height data in the .dem file are ok but
anywhere there is height date it's all messed up.

:(

-- 
Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message

Fabien Hénon wrote:

> So, is there a way I can convert this 'simple binary raster format' ? With
> Photoshop 5 maybe.
> I have to say that I have never heard of this file format.

I had the same problems with files from the server you mentioned.
To open it with Photoshop, do the following :
- with a text editor, open one of the small files (don't remeber the extension),
where you'll find the number of raws and columns;
- open the first large file with PhotoShop, as "raw", and enter the dimensions you
found in the small file.

If you can't do it, tell me and I'll redo the openings to tell you exactly how to
procced.

D. Masnéri

Post a reply to this message

Ken wrote:
> 
> OK,
> 
>  I tried it on Hawaii again and (I really hate to tell you this) the
> results were worse than with your original utility. Before I could
> at least see the islands now they are skewed all over the place. In
> the areas were there is no height data in the .dem file are ok but
> anywhere there is height date it's all messed up.
> 
> :(
> 
DUH!
Yes, this was worse version... I've cancelled message and posted again
version, which should be better. Sorry.

Post a reply to this message

Yes, I tried to convert it with your utility, but it crashes and says :

Exiting due to signal SIGSEGV
General Protection Fault at eip=00002758.....


The file I downloaded is the western part of Africa called W020N40_tar.gz, just in
case....


Fabien Hénon



Vahur Krouverk a écrit :

> Fabien Hénon wrote:
> >
> > So, is there a way I can convert this 'simple binary raster format' ? With
> > Photoshop 5 maybe.
> > I have to say that I have never heard of this file format.
> >
> > If anyone knows if/how it can be converted. I tried to open it as a RAW > file
with
> > different options, but all I get is a blurry image.
> >
> Have you tried my coverter? I've uploaded new version to
> binaries.utilities, which converts those files to POV-Ray .TGA
> heightfield format.

Post a reply to this message

I managed to find a file that read 6000 x 4800 ( width and height)

I tried to open the file with Photoshop as a RAW file with all the possibilities I
could think of, and none of them works..

Thanks if you can help.

Fabien Hénon

"D. Masnéri" a écrit :

> Fabien Hénon wrote:
>
> > So, is there a way I can convert this 'simple binary raster format' ? With
> > Photoshop 5 maybe.
> > I have to say that I have never heard of this file format.
>
> I had the same problems with files from the server you mentioned.
> To open it with Photoshop, do the following :
> - with a text editor, open one of the small files (don't remeber the extension),
> where you'll find the number of raws and columns;
> - open the first large file with PhotoShop, as "raw", and enter the dimensions you
> found in the small file.
>
> If you can't do it, tell me and I'll redo the openings to tell you exactly how to
> procced.
>
> D. Masnéri

Post a reply to this message

Fabien Hénon wrote:
> 
> Yes, I tried to convert it with your utility, but it crashes and says :
> 
> Exiting due to signal SIGSEGV
> General Protection Fault at eip=00002758.....
> 
> The file I downloaded is the western part of Africa called W020N40_tar.gz, just in
> case....
> 
> Fabien Hénon

What operating system are you using? Win95,
98, NT, 2000? What processor? Did you convert whole dem file or part of
it? What options did you use? Does program outputs something before
crashing? Map file shows, that this address belongs to memory allocation
subroutine, do you have enough resources in case of 9x? 
Was it new version or did you used old version?

P.S. I found, that my program does not convert negative values
correctly. I'd like to hear opinions, how they should be converted? One
option is to assign minimum value (i.e. maximum negative value) to level
0
and raise all other points with respect to it.
But this means that sea level will be above zero level and it
could produce problems with sea rendering: it will
be hard to determine correct value for sea color map, even if program
will
output sea level value. Is there other options?

Post a reply to this message

'MicroDEM' is a very easy way to extract and initially display most forms of
DEM data.

I have used it with great success with the same format materials.

Provides an easy way to preview the scene, and make a fly through. Data can
then be saved as .bmp.

DVJ

Ken <tyl### [at] pacbellnet> wrote in message
news:38F717AC.16B7A618@pacbell.net...
>
>
> Vahur Krouverk wrote:
>
> > If my memory serves me correctly, then I've used files from same site
> > and the set of files seems to be OK. File size is probably OK too, my
> > memory failed here: whole package was probably >80 MB. Have you tried my
> > converter (see my previous post)?
>
> I just downloaded a dem from that site and the two utilities I have for
> conversion choked on them too. I then downloaded your utility and while
> it was able to read the file and convert it to a .tga image there was
> erroneous data in the resulting .tga the rendered it useless to me.
> The dem I downloaded is of the Hawaiian Islands (w180n40.dem) which is
> fairly well centered in the data. When converted to tga, with your
> utility, there is a green colored stripe going directly through the
> island chain (directly in the middle of the image) running left to
> right. It takes up a sizable chunk of real estate
>
> Any idea what may be causing that ?
>
> --
> Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
> http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message