Frank,<br><br>The ECW is already in a compressed format, so this means that the image is compressed another 95%? This additional compression is for performance purposes?; does it affect the image quality?<br><br>Thanks,<br>
<br>John<br><br><div><span class="gmail_quote">On 11/30/06, <b class="gmail_sendername">Frank Warmerdam</b> <<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
John Mitchell wrote:<br>> Hi Frank,<br>><br>> I now able to display ECW type files via mapserver within a community<br>> mapbuilder web browser client. I had question on part of the sample map<br>> file that you sent:
<br>> OUTPUTFORMAT<br>> NAME jpeg2000<br>> DRIVER "GDAL/JP2ECW"<br>> MIMETYPE "image/jpeg2000"<br>> FORMATOPTION "TARGET=95"<br>> IMAGEMODE RGB<br>> END<br>><br>> What does TARGET=95 mean?
<br><br>John,<br><br>This means that I am requesting 95% reduction in image size during<br>compression - ie. 20:1 compression.<br><br>> I am having good success (as far as image quality and small size<br>> downloaded to the browser) with displaying my image data as jpeg within
<br>> community mapbuilder as an example<br>> <FormatList><br>> <Format current="1">image/jpeg</Format><br>> </FormatList><br>> But when I try displaying it as a png as an example. I get poor quality
<br>> as far as the color.<br>> <FormatList><br>> <Format current="1">image/png</Format><br>> </FormatList><br><br>You like want PNG24 format. The plain PNG format results in a reduction
<br>to 8bit which causes a lot of damage to the image. The predefined 24bit<br>PNG output format is called "PNG24", and has a mimetype of<br>"image/png; mode=24bit"<br><br>> What application do you use to create your .ECW files?
<br><br>The original ecw file I was serving from was one I downloaded from<br><a href="http://geotorrent.org">geotorrent.org</a>. But I do sometimes use gdal_translate to produce<br>ecw files.<br><br>Best regards,<br>--<br>
---------------------------------------+--------------------------------------<br>I set the clouds in motion - turn up | Frank Warmerdam, <a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a><br>light and sound - activate the windows |
<a href="http://pobox.com/~warmerdam">http://pobox.com/~warmerdam</a><br>and watch the world go round - Rush | President OSGeo, <a href="http://osgeo.org">http://osgeo.org</a><br><br></blockquote></div><br><br clear="all">
<br>-- <br>John J. Mitchell