[mapguide-internals] Raster performance (was Raster providerproblems...)

[Traian Stanev]

My chief concern with dropping down to 8 bit color output is that it means we would have to turn off antialiased drawing. Compare the two attached images to see what happens when you save a map that uses antialiased drawing into a png8 image. I used GIMP to generate the optimal palette for the 8 bit image, which by the way is time consuming also, so regular 8-bit output would likely be worse.
 
Traian
 

	-----Original Message----- 
	From: mapguide-internals-bounces at lists.osgeo.org on behalf of Jason Birch 
	Sent: Sat 4/7/2007 3:22 PM 
	To: MapGuide Internals Mail List 
	Cc: 
	Subject: [mapguide-internals] Raster performance (was Raster providerproblems...)
	
	

	Bob wrote:
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	FYI - MapGuide 6.x has single threaded Raster data and DWG data since
	those formats were first supported. Yes it is a limitation, but one
	users have been living with for years.
	
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	It's probably not a great idea to bring this up right now, but I'd like to talk about raster performance a bit.
	
	>From my point of view (at our usage levels per-request speed is more important than concurrent access) raster data was never the limiting factor with 6.5 as long as it was configured properly for LOD at particular view scales.  My main area of optimisation has always been around vector data... making sure that not too much data is attached to requests, limiting secondary joins, generalizing for small scale display, etc.
	
	With MGOS architectural changes, I have to worry less about vector performance (SDF is still efficient; though multiple indexes would be nice) and more about raster performance.  I'm sure that a lot of this has to do with smooshing the raster data together with the rendered vector data on the server side...
	
	On a recent project, we found that switching overlay generation from PNG to JPG reduced each image from 2MB down to a few hundred K  I wonder if supporting PNG8 would allow for better apparent performance while reducing some of the compression uglyness of JPG.  It seems to for ArcGIS server:
	
	http://priour.wordpress.com/tag/arcgis-server/
	
	Jason