Is there an easy way of taking a topographic map as yoinked from
Terraserver and making a heightfield of it such that each elevation
line and the space to the next line is a single greyscale?
The only way I have of accomplishing this at the moment is going
into PSP and manually putting in a vector point-to-point line over
each elevation line in a new layer...excessively time consuming.
I suppose I could try using a regular 1x1 paintbrush and my Wacom
tablet and drawing the lines in a new layer, but...if there's an
even easier way, I'd like to know about it!

-- 
Tim Cook
http://empyrean.scifi-fantasy.com

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"Timothy R. Cook" wrote:
> 
> Is there an easy way of taking a topographic map as yoinked from
> Terraserver and making a heightfield of it such that each elevation
> line and the space to the next line is a single greyscale?

Are you aware this would lead to a terraced terrain which would be far
from realistic?

If you are having a file of vector lines a possible solution would be to
close all lines which are not yet closed, fill them with the appropriate
color and layer the resulting polygons in the correct height order.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 21 Feb. 2002 _____./\/^>_*_<^\/\.______

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On Fri, 01 Mar 2002 08:36:01 -0500, "Timothy R. Cook"
<tim### [at] scifi-fantasycom> wrote:
> if there's an
> even easier way, I'd like to know about it!

I don't know how accurate is input and how accurate should be output but try
this:

1. Open image with lines in image manipulation software.
2. Assign each height to separate intensity of gray with rule: lowest height
is black, largest height is white.
3. Take filler/bucklet tool and fill each region (and line) of height range
with apropriate gray intensity (I hope lines are closed)
4. Look for largest distance beetween height-lines and perform blur/smooth
operation with this size/2 as radius.
5. Save image and use it as heigh field.

in step 3 if lines are not closed then add extra pixels to close it.

in step 4 you can experiment with lower radius of blur, handy blur with pencil
and/or separate blur for pairs of heights

ABX

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Christoph Hormann wrote:
> Are you aware this would lead to a terraced terrain which would be far
> from realistic?

Seeing's I've no other way of transferring topo data into POV/Moray,
I'll take what I can get.  Plus I do a blur after putting in all the
lines/filling them thereby getting a smoother image...but even then
I get a terraced look.  Even if I could output more than 256 shades
of grey, it'd still be terraced, just at a finer level.

-- 
Tim Cook
http://empyrean.scifi-fantasy.com

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PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
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> I don't know how accurate is input and how accurate should be output but try
> this:
> 
> 1. Open image with lines in image manipulation software.
> 2. Assign each height to separate intensity of gray with rule: lowest height
> is black, largest height is white.
> 3. Take filler/bucklet tool and fill each region (and line) of height range
> with apropriate gray intensity (I hope lines are closed)

Problem with this is the Terraserver/USGS topographic maps aren't just
the
elevation lines.  They also have a red grid, roads, green areas for
trees,
black boxes for buildings, labels for things, et cetera.

-- 
Tim Cook
http://empyrean.scifi-fantasy.com

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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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"Timothy R. Cook" wrote:
> 
> > Are you aware this would lead to a terraced terrain which would be far
> > from realistic?
> 
> Seeing's I've no other way of transferring topo data into POV/Moray,
> I'll take what I can get.  Plus I do a blur after putting in all the
> lines/filling them thereby getting a smoother image...but even then
> I get a terraced look.  Even if I could output more than 256 shades
> of grey, it'd still be terraced, just at a finer level.
> 

I doubt you would have any luck with that method.

There are programs performing height line -> DEM conversion, for example
GRASS:

http://www.geog.uni-hannover.de/grass/index2.html

but they usually produce unnaturally smooth results.  Methods taking into
account the sharp edges typical for terrain are quite complicated and
usually rely on further information like river lines etc.

Christoph

-- 
POV-Ray tutorials, IsoWood include,                 
TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 21 Feb. 2002 _____./\/^>_*_<^\/\.______

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On Fri, 01 Mar 2002 09:15:21 -0500, "Timothy R. Cook"
<tim### [at] scifi-fantasycom> wrote:
> Problem with this is the Terraserver/USGS topographic maps aren't just
> the
> elevation lines.  They also have a red grid, roads, green areas for
> trees,
> black boxes for buildings, labels for things, et cetera.

What the problem to fill all pixels with color different to elevation lines
with background color first. It should be easy possible with any image
manipulation software. IIRC it was possible even with paint in windows.

ABX

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Christoph Hormann wrote:
> but they usually produce unnaturally smooth results.

Considering I'm using the heightfield for an underwater scene,
and the fact that at the scale I'm working with, the vertical
difference of grass is negligible...smoothing is NOT a problem.
-- 
Tim Cook
http://empyrean.scifi-fantasy.com

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PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------

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On Fri, 01 Mar 2002 09:15:21 -0500, Timothy R. Cook wrote:
> Problem with this is the Terraserver/USGS topographic maps aren't just
> the
> elevation lines.  They also have a red grid, roads, green areas for
> trees,
> black boxes for buildings, labels for things, et cetera.

Have you considered just getting a DEM for that area instead?  The DRG maps
aren't really made for trying to get data out of.

If you're really set on using the topo lines, you can get them in vector 
format from the USGS website without all of the extraneous data.

-- 
plane{-z,-3normal{crackle scale.2#local a=5;#while(a)warp{repeat x flip x}rotate
z*60#local a=a-1;#end translate-9*x}pigment{rgb 1}}light_source{-9red 1rotate 60
*z}light_source{-9rgb y rotate-z*60}light_source{9-z*18rgb z}text{ttf"arial.ttf"
"RP".01,0translate-<.6,.4,.02>pigment{bozo}}light_source{-z*3rgb-.2}//Ron Parker

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"Timothy R. Cook" <tim### [at] scifi-fantasycom> wrote in message
news:3C7F8CA0.9700B111@scifi-fantasy.com...
> Christoph Hormann wrote:
> > Are you aware this would lead to a terraced terrain which would be far
> > from realistic?
>
> Seeing's I've no other way of transferring topo data into POV/Moray,
> I'll take what I can get.  Plus I do a blur after putting in all the
> lines/filling them thereby getting a smoother image...but even then
> I get a terraced look.  Even if I could output more than 256 shades
> of grey, it'd still be terraced, just at a finer level.
>
> --

Leveller has a "deterrace" function....

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