Hi Jeff,<br>
<br>
Thanks for the tip - that worked!!<br>
<br>
Jennifer<br><br><div><span class="gmail_quote">On 1/24/06, <b class="gmail_sendername">Jeff McKenna</b> <<a href="mailto:jmckenna@dmsolutions.ca">jmckenna@dmsolutions.ca</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;">
Have you tried setting Chameleon's "image_type" parameter to PNG24 in<br>/config/chameleon.xml?<br><br>jeff<br><br><br><br>Jennifer Zeisloft wrote:<br>> Hello All,<br>><br>> I have been having problems displaying raster imagery from web mapping
<br>> services in MapServer/Chameleon (poor visual resolution, essentially).<br>> I first sought help from the MapServer list (pasted below), but have<br>> discovered that I likely need Chameleon help.<br>><br>
> Specifically, I am wondering how I can specify that 24bit output be<br>> generated from a layer in a web mapping context.<br>><br>> In addition to the responses below, Frank Warmerdam also suggested<br>> adding PROCESSING "DITHER=YES" to the mapfile if I do not specify jpeg
<br>> or png24 in the mapfile output. This did help somewhat. But again, the<br>> problem is that I cannot refer to a mapfile in an xml context file (as<br>> far as I know). So, there must be some other means in Chameleon of
<br>> specifying that the output is 24bit rather than 8bit.<br>><br>> I am grateful for any hints or ideas you can offer!<br>><br>> Thanks!<br>><br>> Jennifer Zeisloft<br>> UW Sea Grant<br>><br>
> ------------------------------------------------------------------------------------------------------------------<br>> >From the MapServer List Discussion:<br>><br>> Greetings All,<br>><br>> We have been noticing that some (but not all) WMS raster images look
<br>> pretty terrible (extremely low resolution compared to what they should<br>> be) when added to our MapServer application. For instance, from<br>> TerraServer (<a href="http://terraservice.net/ogcmap.ashx">http://terraservice.net/ogcmap.ashx
</a>), USGS Digital Ortho<br>> Quads are virtually useless regardless of scale, while USGS DRGs look<br>> decent. Daily MODIS imagery from NASA JPL World Map Service<br>> (<a href="http://wms.jpl.nasa.gov/wms.cgi?">
http://wms.jpl.nasa.gov/wms.cgi?</a>) has also typically been a problem.<br>> And there are others...<br>><br>> I have recently been playing with GDAL to display our own rasters, but<br>> also partially with the hope that it might somehow magically fix this
<br>> problem (of course it hasn't).<br>><br>> I am wondering whether the display problem is local or if it is on the<br>> data custodian's end, and whether this is typically the case. Is there<br>> any way to correct it? If it is at the custodial end, what might be
<br>> done differently to increase the display resolution for WMS clients (so<br>> that we don't make the same mistake)?<br>><br>> I really appreciate any hints or ideas you can offer.<br>><br>> Thanks much!
<br>><br>> Jennifer Zeisloft<br>> UW Sea Grant<br>><br>> ------------------------<br>> Jennifer -<br>><br>> You don't give us much information to go on, other than your dislike of<br>> the results!
<br>><br>> If you're consistently seeing poor-quality results, then there may well<br>> be something systematic you're doing in your map files or MapServer<br>> configuration. I'm assuming you're using MapServer to generate these
<br>> "horrible-looking" images. If you are, for example, requesting<br>> low-color output from high-color images, you're going to see blotchy<br>> output. DRGs are low-color images (only 13 unique colors) so they are
<br>> not as prone to being affected by a low-color output request.<br>><br>> Could you provide an example of the map file and configuration you're<br>> using to retrieve and display these images? There's nothing special
<br>> about the WMS interface that inherently limits image quality - you can<br>> get a perfect reproduction of the source imagery in many cases.<br>><br>> - Ed<br>><br>> Ed McNierney<br>> President and Chief Mapmaker
<br>> TopoZone.com / Maps a la carte, Inc.<br>> 73 Princeton Street, Suite 305<br>> North Chelmsford, MA 01863<br>> Phone: +1 (978) 251-4242<br>> Fax: +1 (978) 251-1396<br>> <a href="mailto:ed@topozone.com">
ed@topozone.com</a> <mailto:<a href="mailto:ed@topozone.com">ed@topozone.com</a>><br>><br>> --------------------------------------<br>> Thank you for responding, Ed.<br>><br>> Actually, these raster data sets are displayed as part of Chameleon
<br>> contexts (so there is no mapfile). I added the USGS orthos to a mapfile<br>> to see if the result was any different and it wasn't (the mapfile code<br>> for this layer is pasted below in any case).<br>>
<br>> The application can be found at<br>> <a href="http://maps.aqua.wisc.edu/lscmp/viewmaps.phtml">http://maps.aqua.wisc.edu/lscmp/viewmaps.phtml</a>. The example data sets I<br>> am referring to can be found in the Wisconsin: Imagery context.
<br>><br>> I have read through the documentation on rasters in MapServer, as well<br>> as searched list archives and have not been able to determine how I<br>> would go about specifying low or high -color output. So, perhaps this
<br>> is part of the problem?<br>><br>> Again, any suggestions are greatly appreciated!!<br>><br>> Jennifer Zeisloft<br>><br>> LAYER<br>> NAME DOQ<br>> STATUS ON<br>> CONNECTIONTYPE WMS
<br>> TYPE RASTER<br>> CONNECTION "<a href="http://terraservice.net/ogcmap.ashx">http://terraservice.net/ogcmap.ashx</a>"<br>> PROJECTION<br>> "init=epsg:4326"<br>> END # Projection
<br>> METADATA<br>> "wms_srs" "EPSG:4326"<br>> "wms_name" "DOQ"<br>> "wms_title"
"USGS Digital Ortho-Quadrangles"<br>> "wms_onlineresource" "<a href="http://terraservice.net/ogcmap.ashx">http://terraservice.net/ogcmap.ashx</a>"<br>> "wms_abstract" "NA - test"
<br>> "wms_keywordlist" "NA -test"<br>> "wms_server_version" "1.1.1"<br>> "wms_formatlist" "image/png,image/jpeg,image/wbmp"<br>> "wms_format" "image/png"
<br>> END # Metadata<br>> END # layer<br>><br>> -------------------------------------<br>> From: Frank Warmerdam <<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a><br>> <mailto:<a href="mailto:warmerdam@pobox.com">
warmerdam@pobox.com</a>>> Mailed-By: <a href="http://lists.umn.edu">lists.umn.edu</a><br>> <<a href="http://lists.umn.edu">http://lists.umn.edu</a>><br>> Reply-To: Frank Warmerdam <<a href="mailto:warmerdam@pobox.com">
warmerdam@pobox.com</a> <mailto:<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a>>><br>> To: <a href="mailto:MAPSERVER-USERS@lists.umn.edu">MAPSERVER-USERS@lists.umn.edu</a> <mailto:<a href="mailto:MAPSERVER-USERS@lists.umn.edu">
MAPSERVER-USERS@lists.umn.edu</a>><br>> Date: Jan 23, 2006 10:57 PM<br>> Subject: Re: [UMN_MAPSERVER-USERS] Horrible Looking WMS Raster Imagery<br>><br>> On 1/23/06, Brent Pedersen <<a href="mailto:bpederse@nature.berkeley.edu">
bpederse@nature.berkeley.edu</a><br>> <mailto:<a href="mailto:bpederse@nature.berkeley.edu">bpederse@nature.berkeley.edu</a>>> wrote:<br>> > have you tried using image/jpeg?<br>><br>> In addition to fetching data from the remote WMSes as
<br>> JPEG, it is also necessary for mapserver to generate 24bit<br>> output (JPEG or PNG24 for instance). I don't know how to<br>> do that with Chameleon myself, but I'm sure there is a setting<br>> somewhere.
<br>><br>> I think Ed is right that the problem is 24bit to 8bit color<br>> conversion with correspondingly poor color resolution.<br>> Given sufficient blotchiness from this conversion it can<br>> even appear that spatial resolution is degraded (though it
<br>> isn't actually).<br>><br>> Best regards,<br>> ---<br>><br>> I set the clouds in motion - turn up | Frank Warmerdam,<br>> <a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a> <mailto:
<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 | Geospatial Programmer for Rent
<br>><br>> ------------------------------------------------<br>> Brent,<br>><br>> Thanks for the suggestion. I switched the output from png to jpeg - but<br>> no change (the jpeg might have looked a little worse??). Still, the
<br>> crux of the matter is, I suppose, that these images are displayed<br>> through a context file. The rasters are coming straight from their<br>> "original" (perhaps) source, which doesn't allow me to specify how the
<br>> image is displayed, but merely that an image is displayed (furthermore,<br>> the context file is automatically generated by the "Save Context" widget<br>> in Chameleon).<br>><br>> And an addendum to my last message: I did find output specifications in
<br>> the documentation<br>> (<a href="http://mapserver.gis.umn.edu/docs/reference/mapfile/outputformat/">http://mapserver.gis.umn.edu/docs/reference/mapfile/outputformat/</a>), but<br>> I don't have the opportunity in this instance to specify the output in
<br>> this sense.<br>><br>> Jennifer<br>><br>> -----------------------------------------------<br>> Hi Frank,<br>><br>> Thanks for the response, Frank. It is sounding more and more like this<br>> is a question I ought to forward to the chameleon list - because I am
<br>> also not sure how to generate 24bit output with chameleon!<br>><br>> I appreciate the much needed direction!<br>><br>> Thanks all!<br>><br>> Jennifer<br>><br><br><br>--<br>Jeff McKenna<br>DM Solutions Group Inc.
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