[mapserver-users] MapScript WMS request

[Smith, Michael ERDC-CRREL-NH]

I use this type of OpenLayers layer (OpenLayers.Layer.MapServer) all the
time and it works great. As an old school cgi user, I find the MapServer
interface more flexible than the WMS one.

Mike

-- 
Michael Smith

Remote Sensing/GIS Center
US Army Corps of Engineers



On 9/9/11  9:39 AM, "Fawcett, David (MPCA)" <david.fawcett at state.mn.us>
wrote:

>Puneet, 
>
>As far as I know, OpenLayers still has support for a layer based on
>MapServer CGI.  Because MapServer can also serve up WMS well, this layer
>type isn't necessarily recommended or as well supported.
>
>http://dev.openlayers.org/docs/files/OpenLayers/Layer/MapServer-js.html
>
>David.
>
>-----Original Message-----
>From: mapserver-users-bounces at lists.osgeo.org
>[mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Mr. Puneet
>Kishor
>Sent: Thursday, September 08, 2011 9:32 PM
>To: Daniel Morissette
>Cc: mapserver-users at lists.osgeo.org
>Subject: Re: [mapserver-users] MapScript WMS request
>
>
>On Sep 8, 2011, at 8:28 PM, Daniel Morissette wrote:
>
>> On 11-09-08 09:02 PM, Mr. Puneet Kishor wrote:
>>> 
>>> On Sep 8, 2011, at 7:43 PM, Daniel Morissette wrote:
>>>> 
>>>> Maybe call $map->save("/tmp/my.map") in your script after the map and
>>>>layer have been populated and paste the result... that may give us a
>>>>hint...
>>>> 
>>> 
>>> wow! this is a super-awesome debugging technique. I have sent you the
>>>map file off list to not pollute the entire list serve.
>>> 
>> 
>> I was able to reproduce the issue with the copy of the mapfile you sent
>>off-list.
>> 
>> It turns out that mappostgis.c's msPostGISLayerGetExtent() is hardcoded
>>to always return
>> 
>> {minx = -25000000, miny = -25000000, maxx = 25000000, maxy = 25000000}
>> 
>> ...and then it returns MS_SUCCESS.
>> 
>> I think this function should either be left unimplemented (this way
>>MapServer would fallback on other mechanisms), or return MS_FAILURE to
>>indicate to the calling code that it didn't do anything useful.
>> 
>> A quick search indicates an open ticket about the issue:
>> 
>> http://trac.osgeo.org/mapserver/ticket/3585
>> 
>> You could bump the ticket and hope someone works on it at the FOSS4G
>>code sprint next week.
>> 
>> The short term fix for you would be to set the "ows_extent" metadata in
>>your layer:
>> 
>>    METADATA
>>      "ows_extent" "-180 -90 180 90"
>>   ...
>>    END
>> 
>
>
>Thanks Daniel. I will bump the ticket. For now, see below --
>
>Using the "my.map" file I sent you, with no further modifications to it,
>I am able to successfully get an image back via
>[http://localhost.local/cgi-bin/gmna?SERVICE=WMS&VERSION=1.1.1&REQUEST=Get
>Map&BBOX=-180,-90,180,90&SRS=EPSG:4326&WIDTH=1200&HEIGHT=600&LAYERS=gmna&S
>TYLES=&FORMAT=image/png&TRANSPARENT=true]
>
>Note, no further modifications is required, that is, not even the
>"ows_extent" "-180 -90 180 90" bit in the layer METADATA. and I still get
>a good image.
>
>
>However, if I use the following program to access the same map file, I
>get the spurious "minx = -25000000, miny = -25000000, maxx = 25000000,
>maxy = 25000000" in the GetCapabilities.
>
>Finally, if I add the "ows_extent" "-180 -90 180 90" line in the layer
>METADATA in the "my.map" file, the GetCapabilities returns the correct
>bounds now, however, the image is still blank.
>
>	#!/opt/local/bin/perl
>	
>	use strict;
>	use mapscript;
>	
>	my $wms = new mapscript::OWSRequest();
>	$wms->setParameter("SERVICE", "WMS" );
>	$wms->setParameter("VERSION", "1.1.1" );
>	$wms->setParameter("REQUEST", "GetMap" );
>	$wms->setParameter("BBOX", "-180,-90,180,90" );
>	$wms->setParameter("LAYERS", "gmna");
>	$wms->setParameter("SRS", "EPSG:4326");
>	$wms->setParameter("WIDTH", "1200");
>	$wms->setParameter("HEIGHT", "600");
>	$wms->setParameter("FORMAT", "image/png");
>	$wms->setParameter("TRANSPARENT", "true");
>	
>	my $map = new 
>mapscript::mapObj("/Users/punkish/Sites/test/mapscript/my.map");
>	
>	if(!$map) {
>		warn "New mapObj() error: $mapscript::ms_error->{message}\n";
>	}
>	
>	my $io = mapscript::msIO_installStdoutToBuffer();
>	my $dispatch_out = $map->OWSDispatch( $wms );
>	printf "%s\n", mapscript::msIO_getStdoutBufferString();
>
>I have now spent an enormous amount of time on this, and for now, I have
>to move on. This is just not working out. Maybe I will try some other
>technique, perhaps this mode=tile to see if I can get MapServer powered
>maps in my apps.
>
>Thanks much for your help. If you (or anyone else) can come up with a
>bright idea, I will be happy to try it.
>
>Puneet.
>
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