Remote sensing details aside, sounds like you are running into the dreaded
MI raster resampling feature.  MI can't print 24 bit color at 24 bit to
postscript printers.  It resamples the raster to 8 bit to print.  That isn't
the problem.  The problem is that it uses the Windows color pallet for the
resample, thus your images look like they are at a low resolution, when in
reality they do not have enough colors to properly represent the image.

Scan your images at 1200 dpi, but if you are going to print them in MI then
you will have to resample them to 8 bit yourself with Photo Editor.  Just
make sure that when you resample them you have PE create an optimized
pallet.  The images will degrade slightly, but most will not be able to
distinguish the difference.

You are going to run into the same problem with Mr. Sid files.  That is why
I do not believe that Mr. Sid is a good solution for MI.  Besides ER Mapper
will give you a better compression tool for free and ER Mapper's format has
plug-ins for MI, AV, AutoCAD, PhotoShop and other apps.  But even with ER
Mapper you will run into a printing problem.

There is a company, Engineering Mapping Solutions that has a good solution.
Their product EMSView is a stand alone viewer that will display your
compressed images as a single image and export them out to all major GIS
apps in 24, 16 and 8 bit TIFFs (world and tab files included).  They have
even developed a mbx that will allow you to import an image from within MI.
Their number is (602) 870-7811.

Hope this helps,

Bill Landis...
Information Management Director, Global Mapping Services
CB Richard Ellis
P 602 735 5233  F 602 735 5655
"If at first you do succeed, try not to look astonished."  - unknown

                -----Original Message-----
                From:   Steven Heapy [SMTP:[EMAIL PROTECTED]]
                Sent:   Wednesday, July 14, 1999 7:15 PM
                To:     'MapInfo-L'
                Subject:        MI Aerial Photography - Printing and Storage

                Our Council has just had some aerial photography flown at
1:5000 and are
                investigating at what DPI we should have this scanned at ie
600 or 1200
                DPI   

                We are currently testing both, obviously the 1200 requires
more storage
                and cost but gives an improved image on the screen and
prints better.
                However both images that are printed through MapInfo 5.5 in
the layout
                seem to loose a fair amount of quality compared to being
printed in say
                Photo Editor.

                Also has anyone used and printed images compressed with Mr
Sid over a NT
                network.

                All comments, sugestions and ideas regarding DPI
(resolution), storage
                and printing would be appreciate

                Regards
                Steve
        
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