[OpenLayers-Users] Behaviour discrepancies between maps (application/openlayers from GeoServer VS OpenLayers JS code)

[Eric Lemoine]

Hello. Regarding the performance issue: in the first case three images
are requested from GS, one for each WMS layers configured in OL.
Althoug i'm not a GS expert, i think that in the second case only one
image is requested - the three layers are combined in a single image.
Does that make any sense ? Eric

2008/5/22, springrider <springrider at hotmail.com>:
>
> Hello,
>
> I tried to play with the different output format (gif,PNG8) but the display
> of the maps is always very slow when i zoom in. Moreover, i am still having
> this uncorrect display of the plolygons.
>
> If anyone could help a lost newbie, I would be very thankful...
>
> Sylvain
>
>
> springrider wrote:
>>
>> Good afternoon
>>
>> Sorry for the long title. I am developing a web application based on
>> oracle, GeoServer and Openalyers. It works great but i have found some
>> performance discrepancies and display problems between maps in a Web page
>> generated through OL Javascript code and maps generated from Geoserver
>> using the format="application/openlayers".
>>
>> Here the code I am using to generate my map through JS code (Sorry
>> everything is on my development server and can not be accessed from
>> outside):
>>
>> var myMap = new
>> OpenLayers.Map('mapResourceFIRMS',{numZoomLevels:24,projection:
>> "EPSG:4326" });
>> 	
>> myMap.addControl(new
>> OpenLayers.Control.LayerSwitcher({'ascending':true}));
>> myMap.addControl(new OpenLayers.Control.OverviewMap());	
>>
>> var wms = new OpenLayers.Layer.WMS("All
>> Areas","http://193.43.36.236:8080/geoserver/wms?service=wms",
>> 								{layers:'fifao:FAO_DIVISION'},{wrapDateLine: true}
>> 								);
>> 	wms.addOptions({isBaseLayer: true});	
>> 	
>> var wms_continent = new
>> OpenLayers.Layer.WMS("Continent","http://193.43.36.236:8080/geoserver/wms?service=wms",
>> 								{layers: 'fifao:CONTINENTS_LN1',
>> 								transparent:"true"},{wrapDateLine: true}
>> 								);
>> 	wms_continent.addOptions({isBaseLayer: false});   	
>>
>> 	myMap.addLayer(wms);	
>> 	myMap.addLayer(wms_continent);	
>> 	myMap.zoomToMaxExtent();
>>
>> I obtain a map which works correctly but when i zoomed in, it always takes
>> 10 seconds to display the new extended view.
>>
>> On this other hand, when i  use the openlayer format of Geoserver through:
>> http://193.43.36.236:8080/geoserver/wms?bbox=-198.0,-97,198.0,99&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:FAO_DIVISION,fifao:CONTINENTS_LN1&width=600&height=290&srs=EPSG:4326
>> I obtain the same kind of map with less functionnalities but when i zoom
>> in, it is displayed automatically, very smoothly. No additional delay is
>> required to display the zoomed view.
>>
>>
>> Moreover i have a problem of display: When i zoom in on specific polygons
>> in the map based on OpenLayers JS library in my Web page, these polygons
>> are not correctly represented:
>>  http://www.nabble.com/file/p17364274/Untitled-2%2Bcopy.jpg
>> : See in red the limits of the polygons which are missing.
>>
>> Here, an screenshot of the same area from a map generated from Geoserver
>> using the "application/openlayers" format and having the correct border
>> for the polygons:
>>  http://www.nabble.com/file/p17364274/Untitled-4%2Bcopy.jpg
>>
>> I don't understand why 2 maps showing the same data which should be based
>> on the same mechanism, behave so differently in term of loading
>> performance and layers display. In fact, I would like to have my map
>> nested in my web page and built using Openlayers JS code behaving the same
>> as the one which can be generated through GeoServer.
>>
>> Moreover, if you have any hints or tricks for improving the speed of
>> display when zooming, i would be very interested.
>>
>> Hope it is clear enough.
>>
>> Thanks
>>
>> Sylvain
>>
>
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