Thanks for the response, the output options you give are the ones I have
used in the WMS for the ecw image, the results for which you can see from
using the following urls in any WMS 1.1.1 compliant viewer:
PNG output, very large file size but high quality:
http://203.202.1.211/pngwms.asp?SERVICE=WMS&VERSION=1.1.1&REQUEST=getcapabilities
JPEG output, small file size but very low quality:
http://203.202.1.211/jpgwms.asp?SERVICE=WMS&VERSION=1.1.1&REQUEST=getcapabilities
What I do not understand is why (when using the same ecw image) does the
JPEG output give very good quality results and a small filesize using a CGI
call, but such poor results in a WMS which uses exactly the same output
options?
Any advice most welcome,
Gareth
----- Original Message -----
From: "Jacolin Yves" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, August 30, 2006 11:21 PM
Subject: Re: [UMN_MAPSERVER-USERS] WMS using ecw file
Le Mardi 29 Août 2006 15:31, Gareth Heinz a écrit :
Hi all,
Serving a satellite image ECW (approx 4GB file) as a MapServer CGI
consumable. While a 24bit PNG looks great, the filesize can be quite huge,
therefore I've modified to serve it as a JPEG with QUALITY set to 100.
This
still looks good and gives a very small filesize compared to the PNG.
Now here is the main question, when serving the same layer as a WMS
service, the JPG looks really washed-out, where as the PNG while looking
great has too big a filesize for the end-users. So I was wondering if
there
was a bug with Mapserver or GDAL (as I take it MapServer uses GDAL to
serve
ECW's), or if anyone out there has a solution?
Using MapServer 4.8.3 on Windows 2003 serving via IIS.
TiA.
Gareth
To improve your output you have several ways. Some of them got some
contrains.
I use ECW and try output in png (big but not good) and jpg not so good. Some
others parameters for both jpeg and png not output a good images.
Here my output format for PNG :
OUTPUTFORMAT
NAME png
DRIVER "GD/PNG"
MIMETYPE "image/png"
IMAGEMODE RGBA
EXTENSION "png"
FORMATOPTION "INTERLACE=OFF"
TRANSPARENT OFF
END
For jpeg :
OUTPUTFORMAT
NAME jpeg
DRIVER "GD/JPEG"
MIMETYPE "image/jpeg"
IMAGEMODE RGB
EXTENSION "jpg"
FORMATOPTION "INTERLACE=OFF"
FORMATOPTION "QUALITY=100"
END
You can change QUALITY parameter.
Hope it will help to improve your output.
Regards,
Y.
--
Yves Jacolin
http://yjacolin.gloobe.org
----
Stagiaire Conservatoire Régional des Espaces Naturels de la région Centre
http://cahiersnaturalistes.free.fr/cpnrc/
----
- Qu'est-ce que cela peut faire que je lutte pour la mauvaise cause
puisque je suis de bonne foi?
- Et qu'est-ce que ça peut faire que je sois de mauvaise foi
puisque c'est pour la bonne cause. (Jacques Prévert)
