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20050627: viewing McIDAS AREA files in IDV

>From: "David Fitzgerald" <address@hidden>
>Organization: Millersville University
>Keywords: 200506271844.j5RIiONi017398 IDV AREA files

Hi Dave-

>I pulled some archived GOES-12 images from the NOAA CLASS archives.  The
>images are in McIDAS AREA format.  I am trying to view these images in
>IDV without any luck.  The images are on my NFS file system and I select
>Mcidas AREA files as the Data source type.  I get the background map,
>but the image is solid white for all of my images, regardless whether
>the image is Visible, IR or Water Vapor.  Is this a know problem and is
>there a work around?

The problem is most likely that the images are not calibrated, so
you are seeing RAW values that are greater than 256 (white end of the
normal grey scale).

I'm not sure if the CLASS system allows you to specify a calibration
(e.g. brightness), but if it does, request them as brightness values.
Otherwise, you'll have to increase the range of the color table, by
right clicking on the color table and using the Change Range menu.
The GVAR imager stores 10 bits left justified in a 16-bit word
(retaining the sign bit)....so this has a range 0-32767.  In 
the 1.2RC1 version, you can set the color table range based on
the data from the Change Range widget.

Don
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