| opening and display large file [message #21572] |
Tue, 29 August 2000 23:56  |
Sylvain Carette
Messages: 19
Registered: May 2000
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Junior Member |
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<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
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<tt>Hi</tt>
<br><tt>How do you manage to display very large images? What is the options?</tt>
<br><tt>From the manual, it seem that using "assoc" is a winner but maybe
with one little example it would be more clear how can this be (It seem
to me that it is an important aspect of programming with IDL since most
of the time you'll deal with larger than memory files).</tt>
<br><tt>Even with assoc, dont you still have to copy from the file to an
array before display?</tt>
<br><tt>I dont decipher exactly why and when to use readu or read_binary,
the file pointer, assoc or writing to an offscreen buffer.</tt><tt></tt>
<p><tt>I tried to open and display a GTOPO30 tile (4800 x 6000 int). tv
could not display it - froze. I tried "slide_image" but it didnt scroll
with "retain=1" while "retain=2" and "retain=3" result in windows error
and crash.</tt><tt></tt>
<p><tt>Since most of my data fall in the 30mb to 610 mb range, I need absolutely
to open and display very large file. What is available? Pointers, sample
code, library, ideas, etc, I'm listening.... Just knowing that it have
to be handled on your own or that IDL provide facility (that they forgot
to explain in the manual) to deal with this will already be invaluable</tt><tt></tt>
<p><tt>Thanks</tt><tt></tt>
<p><tt>Sylvain Carette</tt>
<br><tt>VRML designer-composer</tt>
<br> </html>
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| Re: opening and display large file [message #21597 is a reply to message #21572] |
Fri, 01 September 2000 01:24  |
Sylvain Carette
Messages: 19
Registered: May 2000
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Junior Member |
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<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
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<tt>Martin Schultz wrote:</tt>
<blockquote TYPE=CITE><tt>Sylvain Carette wrote a lot of words but not
too many facts:</tt>
<br><tt>></tt></blockquote>
<tt>Yea, too many words.... and begin to drift away of what I intend.</tt>
<blockquote TYPE=CITE><tt> You never gave us any specs of your system
(not that I could do</tt>
<br><tt>anything with it, but I know of some people who might get</tt>
<br><tt>interested in helping you if you provided some more technical</tt>
<br><tt>infos). Before you blame IDL for not being able to do what you</tt></blockquote>
<tt>I dont want to trash or blame idl; I want to understand *why* or/and
where I did wrong and understand the working relationship between functions.
IDL absence of design just make thing harder that's all. But once you can
get over this, I suppose you can get some fun using its powerful feature
while avoiding the rest. I'm from a C, C++, Java background applied for
sound and 3D and I even write some Autolisp. If its necessary, I'm even
willing to use assembly which beat idl all the way on absence of design...
I know that when I'll have a "Hello Image" up and running, things will
start to make sense.</tt>
<br><tt>Now I'm still trying to make sense of it. I'll try to follow David's
advice (in some of the post up there) to have more focused requests (and
yours to have less verbose comments).</tt>
<br><tt>As for my setup: IDL5.3, PIII 600 250mb 20g Diamond Viper550 16mb
OpenGL and (almost shame to tell) Windows98....</tt>
<blockquote TYPE=CITE><tt>Please note: for some projects, selling a piano
is not enough.</tt>
<br><tt>What you really seem to be in need of is a solid buisiness model.</tt></blockquote>
<tt>Your right, I need $70,000 for this project (in which gathering and
proccess raster data represent only a small fraction of the work - mostly
cad and vrml) but I'm faced with the chicken and egg problem: no demo,
no money, no money, well I must break the cycle so I sell my piano and
buy IDL...</tt><tt></tt>
<p><tt>Sylvain Carette</tt>
<br><tt>VRLM designer-composer</tt>
<blockquote TYPE=CITE><tt>Martin</tt><tt></tt>
<p><tt>--</tt>
<br><tt> [[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[ </tt>
<br><tt>[[ Dr. Martin Schultz Max-Planck-Institut fuer Meteorologie</tt>
<br><tt>[[</tt>
<br><tt> [[ &nbs p; &nbs p; &nbs p;
Bundesstr. 55, 20146 Hamburg</tt>
<br><tt>[[</tt>
<br><tt> [[ &nbs p; &nbs p; &nbs p;
phone: +49 40 41173-308</tt>
<br><tt>[[</tt>
<br><tt> [[ &nbs p; &nbs p; &nbs p;
fax: +49 40 41173-298</tt>
<br><tt>[[</tt>
<br><tt>[[ martin.schultz@dkrz.de</tt>
<br><tt>[[</tt>
<br><tt> [[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[ </tt></blockquote>
<tt></tt></html>
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