[OpenLayers-Users] transparent param not sent to WMS service

[myOpenLayersUName]

Hello, 

If there is something I am doing incorrectly in trying to access the
railway_30m layer (below) transparently, please let me know. Otherwise, I
thought this was something I should draw someone's attention to. 

Although this item is somewhat related to
http://n2.nabble.com/WMS-transparent-TRUE-versus-true-td1823416.html#a1823416
and http://trac.openlayers.org/ticket/678 (which was, I believe, submitted
to address the problem reported in the first link), I don't believe those
items dealt with actually trying to set transparency on a WMS layer as
suggested. 

In OpenLayers 2.8, given the following example: 

    var options = { 
        projection: "EPSG:4269", 
        maxExtent: new OpenLayers.Bounds(-135, 38, -50, 78), 
    }; 
    this.map = new OpenLayers.Map('map', options ); 

    var CTISwms = new OpenLayers.Layer.WMS( "CTI-S WMS", 
        "http://wms.sst-sw.rncan.gc.ca/wms/toporama_en", 
        {layers: 'railway_30m', format: 'image/png'}, 
        {isBaseLayer: false, visibility: true, transitionEffect: 'resize'}); 
    this.map.addLayers([CTISwms]); 

    var CTIS_wms_limits = new OpenLayers.Layer.WMS( "CTI-S WMS, limits", 
         "http://wms.sst-sw.rncan.gc.ca/wms/toporama_en", 
        {layers: 'limits', format: 'image/png'}, 
        {isBaseLayer: true, visibility: true, transitionEffect: 'resize'}); 
    this.map.addLayers([CTIS_wms_limits]); 

    this.map.zoomToMaxExtent(); 


I have been unable to set the railway_30m layer to be transparent using any
of the following syntax: 

    var CTISwms = new OpenLayers.Layer.WMS( "CTI-S WMS", 
        "http://wms.sst-sw.rncan.gc.ca/wms/toporama_en", 
        {layers: 'railway_30m', format: 'image/png'}, 
        {isBaseLayer: false, transparent: true, visibility: true,
transitionEffect: 'resize'}); 

    var CTISwms = new OpenLayers.Layer.WMS( "CTI-S WMS", 
        "http://wms.sst-sw.rncan.gc.ca/wms/toporama_en", 
        {layers: 'railway_30m', format: 'image/png'}, 
        {isBaseLayer: false, transparent: "true", visibility: true,
transitionEffect: 'resize'}); 

    var CTISwms = new OpenLayers.Layer.WMS( "CTI-S WMS", 
        "http://wms.sst-sw.rncan.gc.ca/wms/toporama_en", 
        {layers: 'railway_30m', format: 'image/png'}, 
        {isBaseLayer: false, visibility: true, transitionEffect: 'resize',
params: {TRANSPARENT: true}}); 

    var CTISwms = new OpenLayers.Layer.WMS( "CTI-S WMS", 
        "http://wms.sst-sw.rncan.gc.ca/wms/toporama_en", 
        {layers: 'railway_30m', format: 'image/png'}, 
        {isBaseLayer: false, visibility: true, transitionEffect: 'resize',
params: {TRANSPARENT: "true"}}); 


None of the above will actually send the TRANSPARENT parameter in the
request to the WMS service. The only way I was able to get the request to be
sent with that parameter and to get the layer to display transparently was
as follows: 

    var CTISwms = new OpenLayers.Layer.WMS( "CTI-S WMS", 
        "http://wms.sst-sw.rncan.gc.ca/wms/toporama_en?transparent=true", 
        {layers: 'railway_30m', format: 'image/png'}, 
        {isBaseLayer: false, visibility: true, transitionEffect: 'resize'}); 


Also, I noticed while investigating this that both WMS.js and
ArcGIS93Rest.js assume that params.TRANSPARENT is a string and do not handle
boolean anymore as suggested by the fix noted above. 

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