ogc features over orthophoto over dem

[Jim Koutsovasilis]

Hello Andrea,

not sure about this, but could you try the following:

> ScalarMap elevationAlphaMap = new ScalarMap(demElevation,
Display.Alpha);
> display.addMap(elevationAlphaMap);

and comment out the lines:
> ScalarMap alphaMap = new ScalarMap(alphaType, Display.Alpha);
> display.addMap(alphaMap)

This will map elevation to alpha, meaning that the hill tops will be
solid, while the valleys will be transparent (or the other way
around...) This is probably not what you wanted though, as you were
using the RGBA values from the image to map the A component of RGBA to
Display.Alpha.

Can you confirm that the original image has alpha values in it? I don't
know what visad does if you give it an RGB image, but then treat the
range as RGBA.

(Don't think this is much help)

Regards,
Jim.



-----Original Message-----
From: Andrea Antonello [mailto:andrea.antonello at gmail.com]
Sent: Tue 14/11/2006 8:29 PM
To: Jim Koutsovasilis
Cc: visad at unidata.ucar.edu
Subject: Re: RE: ogc features over orthophoto over dem


Thanks Jim,
the alpha sucks a lot of additional ram, so I switched it off.
Good you asked, since something very strange happens when using alpha:
http://www.jgrass.org/cgi-bin/moin.cgi/HowItIsGoingWithVisad?action=sho
w

The photo behaves like having alpha on itself (you can see the
overlays), but it doesn't. You can see the axes, but not the map below.

I also tried to do the alpha with a ConstantMap[], but I went out of
memory with 2 gigs of dedicated ram. And that on a raster of about
200x200. This hurts.

Any idea about the transparency problem?

Andrea






* [A.D. 14/11/06 09:49], Jim Koutsovasilis <J.Koutsovasilis at bom.gov.au>
probably wrote:
> Hello Andrea,
> 
> your screenshot is very impressive and inspiring.
> 
> Most of your Display.Alpha code is commented out - I am wondering how
> the screenshot would have looked with transparency turned on.
> 
> Regards,
> Jim.
> ---
> Jim Koutsovasilis
> CSSB / Communications / AMDISS
> Australian Bureau of Meteorology
> 
> Phone: +61 3 9669 4303
> Email: jimk at bom.gov.au 
> 
> 
> -----Original Message-----
> From: owner-visad at unidata.ucar.edu
[mailto:owner-visad at unidata.ucar.edu]
> On Behalf Of Andrea Antonello
> Sent: Tuesday, 14 November 2006 05:28
> To: visad at unidata.ucar.edu
> Subject: ogc features over orthophoto over dem
> 
> 
> 
> I prototyped around a little bit adding also shapefiles to my testcase
> and I must say: visad rocks!
> 
> I have huge performance problems, which I hope to resolve somehow
later.
> 
> I put the resulting screenshot at:
>
http://www.jgrass.org/cgi-bin/moin.cgi/HowItIsGoingWithVisad?action=sho
w
> I hope someone is interested in this first draft and has some ideas on
> how to do things better. I welcome all critics (Don Murray, I wasn't
yet
> able to get things work following your advices, I will come back on
that
> later).
> 
> I have a couple of rather different questions I would like to post, in
> the hope they are not too scattered.
> 
> - in visad, is there some kind of caching system that gives the
> possibility to work with huge files that can't be kept in memory? Kind
> of tiling mechanism. LIDAR and friends are a now used reality, has
> anyone experience?
> 
> - in the image I made the river with a Gridded3DSet. I'm not sure if
> that is the proper way. Should I use some VisadLineArray?
> 
> - also, I had to elevate the river of some meter, since in certain
parts
> it went below the elevation model (which by the way is right, since
the
> river is made of coarser points as the dem and the lines in some parts
> "intersect" the dem). Has anyone a better idea to overlay the
shapefile 
> over the dem?
> 
> - I tried to simulate a line with borders by painting a thinner after
a
> thicker one of different color. The result is weak as expected, is
there
> any way to do styling of lines (apart of dashing, which I read is
> supported)?
> 
> And last but not least (even if really not so important :)): 
> - has anyone an idea about how to put a filled polygon over the dem? I
> tried as a joke to do it with Delauny, but it doesn't permit 3D.
> Perhaps the best would be to create an image and use it as a texture
> over the dem and photo (does this last sentence make a sense?).
> 
> 
> Thanks in advance for any comment.
> Andrea
> 
>
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-- 
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Andrea Antonello
Environmental Engineer
tel.     +39 0471 068065  
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email:   andrea.antonello at hydrologis.com

"Let it be as much a great honour to take as to give learning,
if you want to be called wise."
Skuggsja' - The King's mirror - 1240 Reykjavik
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