[mapguide-users] Render services image formats

[Traian Stanev]

Toy can try  to split the raster data out into a tiled base layer, which uses JPEG format. Then use PNG8 format for the vector data (either tiled base layer or dynamic).

This would move most color variation to the JPEGs, which would then free the PNG8 color table generation to work with a much smaller color map and thus do a better job at preserving the antialiasing shades.

Traian

P.S. I am not sure if it is possible to have JPEG base layers though...



From: mapguide-users-bounces at lists.osgeo.org [mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Gary Morin
Sent: Thursday, March 20, 2008 5:58 AM
To: mapguide-users at lists.osgeo.org
Subject: [mapguide-users] Render services image formats

Hi

I've been investigating the render services image formats in an attempt to improve performance over the internet

My first observation, it appears in MGOS 2 setting the image format in serverconfig.ini does not affect the formats being served, it was only when I edited the ajaxmappane.templ did I see a difference.

I know the default is PNG, but we can change it JPG and with MGOS2 PNG8.

The problem is, with PNG the map images look great, but the download size is enormous, I'm using some raster maps and the downloads are in the region of 1.5mb. on my internet connection it is taking in the region of 6 seconds to display the map after a pan.

If I switch to JPG the download is much faster, the downloaded images are around 250K, but the quality is poor, some text and labels are now unreadable.

I have also tried the new PNG8 format, but its results were very similar to JPG, image quality is poor.

Many of my clients are use to working with the old MG 6.5, even with raster files being served it performance was great.

Is there a way to alter the compression ratio of a format or any plans to allow this to be done in the future?

Thanks

Gary






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