In article <web.3f5641e0fd79e95a78c628a10@news.povray.org>,
 "saleem" <nomail@nomail> wrote:

>     1.I'm using a PNG file as a height field (DIGITAL TERIAN MODEL - DTM),
> this height field is imported to pov-ray to be in size of 1,1,1, I would
> like to translate and         rescale the height field back to it's real
> size and location.

The "real" size and location is whatever you need it to be. POV 
coordinates have no relation to real-world units, and certainly no 
relation to coordinates on a globe.


> Are the pixels centers placed on the corners or are they
> shifted 0.5 pixel inside form each direction ? (Should I use a factor for
> translation of :  dx = x0 - 0.5*grid_dx ?). is the image map (png file)
> scaling concept similar also to height field scaling and translation
> concept?

I really have no idea what you're asking here...but it sounds like you 
really don't understand how image maps and height fields work. I suggest 
you go back and read the documentation, maybe look at the earlier 
threads in these groups.


>  2. I'm defining the camera according to right_length vector, I know that
> the pixel size in the camera plan is X (1.5 micro m), how to define the
> length of right vector: X * columns  or X * (columns -1), generally speaking
> how pov ray calculate the ray vector for intersection when using the trace
> function ?

Again, I have no idea what you're asking. You may be going at it the 
wrong way, try describing exactly what you're attempting to do rather 
than assuming it must be done a certain way.


>  3. How can I get out of pov ray X,Y,Z of the intersections ? I have added
> also building to scene (group of poly)

Look up the trace() function.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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