[Mapserver-users] Size of images in ImageCatalog

[Ed McNierney]

Jeff -

Just leave them as independent quadrangles.  You should pay some attention to the organization and compression of your TIFF imagery, so that it's easy for MapServer to "look" at the portion of each image that's required.  And if you're displaying the DRGs at "zoomed out" scales (small-scale display) you might want to considering building image pyramids with GDAL to speed access.

But as far as your specific question goes, I've got almost 60,000 DRGs indexed as individual quads (no chopping up) and that's never been a performance concern.

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242 

-----Original Message-----
From: Jeff Berry [mailto:jeffb at erlandsen.com]
Sent: Wednesday, June 11, 2003 3:43 PM
To: MapServer
Subject: [Mapserver-users] Size of images in ImageCatalog


I have DRGs for the State of Washington and I'm struggling with how to tile
them for display in MapServer.  I've projected and clipped the collars off,
and am wondering wether I should just keep them at 7.5' quadrangles or clip
them smaller to say 1.5' blocks.  So, I guess my question is...are smaller
images necessarily better when in an image catalog for MapServer?  Is it
faster for MapServer to look at say up to 8 smaller images that are around
2-3 Mb each, or is it faster to look at 2-4 larger images that are around
7-8 Mb each in to generate the final map?  Maybe there is no significant
difference.  Hope that makes sense.

Jeff Berry
GIS Analyst
Erlandsen & Associates
P.O. Box 2029
Chelan, WA 98816
(509) 682-4189
jeffb at erlandsen.com

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