Raster formats

Doug Nebert ddnebert at usgs.gov
Fri Nov 19 15:12:36 EST 1999


All:

I am seeing strange moire patterns in the global elevation 
data images (TIFF) as rendered through the mapserver, although 
the data itself does not seem to exhibit these checkerboard 
patterns. I am not sure where the pattern is being introduced 
but it is so regular that it seems like a resampling artifact 
when presented. 

I was wondering if use of JPEG or PNG might change this and 
if 3.3 will be allowing specification of image type. If I 
could switch the format (should be one of the get parameters 
[hint: this will be expected in OpenGIS WMT specs]) in the 
GET request then I can view the same data side by side...

Anyone else experience these kinds of patterns or finding 
solutions to them?

-- 
Douglas D. Nebert
Clearinghouse Coordinator 
FGDC Secretariat	Phone: +1 703 648 4151	Fax: +1 703 648-5755	
Pager Messaging: 	http://fgdclearhs.er.usgs.gov/dougmsg.html



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