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Reply To: | Maps, Air Photo & Geospatial Systems Forum |
Date: | Wed, 10 May 2006 08:28:52 -0500 |
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-------- Original Message --------
Subject: Large format capture systems
Date: Tue, 09 May 2006 23:02:15 -0700
From: Dr. Virginia R. Hetrick <[log in to unmask]>
To: Maps, Air Photo & Geospatial Systems Forum <[log in to unmask]>
Hi, Jon -
You might take a look at the following two technologies:
1. A device called a SmartBoard which uses its own nominally colored
"markers" that you could use to trace with. Pretty expensive (around
$10,000 US for one as I recall). Problem is that the spatial resolution
of the "markers" which operate by interrupting a grid of light beans is
pretty course.
2. A better solution might be to use a large scale digitizing tablet,
say 1.5 meters or 2 meters square, which will normally have a
light-colored surface. You should be able to mount it with the surface
in a vertical position with the projector system centered on the
digitizing tablet.
Some years ago I wound up digitizing the polygons of a classified,
projected, Landsat image after I had digitally rectified the image of
some Atlantic barrier islands to a map projection. I found the real
problem was how to avoid getting my head (or other body parts) in the
way while tracing the projected image. By the time I was done, I had
pretty well gotten the hang of it. To make my life easier, I used a
cross-hair device to do the tracing because I could handle it without my
hand (or head) getting in the way. I figured that, if the viewing angle
to the cross-hair was consistent, then all the digitized areas would be
pretty good.
HTH.
virginia
--
\ / Virginia R. Hetrick, here in sunny California
0 Voicemail: 310.471.1766 Email: [log in to unmask]
Oo "There is always hope."
My fave: http://www.washington.edu/cambots/camera1_l.gif
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