Horrible Looking WMS Raster Imagery

[Brent Wood]

Hi Jennifer,

> 
> Greetings All,
> 
> We have been noticing that some (but not all) WMS raster images look
> pretty terrible (extremely low resolution compared to what they should
> be) when added to our MapServer application.  For instance, from
> TerraServer (http://terraservice.net/ogcmap.ashx), USGS Digital Ortho
> Quads are virtually useless regardless of scale, while USGS DRGs look
> decent.  Daily MODIS imagery from NASA JPL World Map Service
> (http://wms.jpl.nasa.gov/wms.cgi?) has also typically been a problem.
> And there are others... 

A couple of issues I noticed when starting out with mapserver a few weeks
ago...

If your source images are 24 bit, & mapserver is outputting 8 bit, expect
losses. Have you tried mapserver set to png24 as its output format?

Also, (though this applies more to vectors & text in my very limited
experience) if your mapserver set output size is not the same as that in your
html template where you display the image, you can get some poor quality output
when the browser scales the image to fit the hole you set for it. 

As an OS GIS & learning mapserver user in a primarily maritime (fisheries/
biodiversity/oceanography) environment, I'm particularly interested in others
also using these tools in a maritime environment. Any chance of letting me know
(off list?) what you are doing where??


Cheers,

   Brent Wood