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</o:shapelayout></xml><![endif]--></head><body lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>List,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I am in desperate need of assistance on this problem. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have a number of GEOJSON files that I want to allow the user to select from. They can only have one Geojson file active at any one time so I must remove the last before loading the next. They can select from a list in a menu object inside the Toolbar.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>No problem listing the files in a menu list and the first file loads just fine and the app sets itself to the BBox of the geojson group of vectors which can be a mix of point, lines and polygons.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Subsequent files load Ok as well but my problem is when I select the second or next geojson file I get an error on the execution of the “featuresadded” event when doing the <i>getDataExtent. </i>Firebug tells me that GeoExt.js line 38 returns with ”<span class=errormessage>this.layer is null” for the next file load.<o:p></o:p></span></p><p class=MsoNormal><span class=errormessage><o:p> </o:p></span></p><p class=MsoNormal><span class=errormessage>The actual zoomtoextent works as well but try as I may I cannot remove this error.<o:p></o:p></span></p><p class=MsoNormal><span class=errormessage><o:p> </o:p></span></p><p class=MsoNormal><span class=errormessage>I have listed my </span>initializeMarkup<span class=errormessage> function below which is called from the menu in a handler for each file load. This is pretty much how the examples do it but I’m not sure why this error is occurring on the next file load.<o:p></o:p></span></p><p class=MsoNormal><span class=errormessage><o:p> </o:p></span></p><p class=MsoNormal><span class=errormessage>Maybe someone can see an obvious error in my code?<o:p></o:p></span></p><p class=MsoNormal><span class=errormessage><o:p> </o:p></span></p><p class=MsoNormal><span class=errormessage>Thanks in anticipation.<o:p></o:p></span></p><p class=MsoNormal><span class=errormessage><o:p> </o:p></span></p><p class=MsoNormal><span class=errormessage>Cheers, Brad....</span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>function initializeMarkup(newSourceData)<o:p></o:p></p><p class=MsoNormal>{<o:p></o:p></p><p class=MsoNormal> // remove any existing GEOJSON loaded layer<o:p></o:p></p><p class=MsoNormal> if(markupLayerLoaded)<o:p></o:p></p><p class=MsoNormal> {<o:p></o:p></p><p class=MsoNormal> markupLayerLoaded.destroy(); <o:p></o:p></p><p class=MsoNormal> markupLayerLoaded=null;<o:p></o:p></p><p class=MsoNormal> saveStrategy.destroy();<o:p></o:p></p><p class=MsoNormal> saveStrategy=null;<o:p></o:p></p><p class=MsoNormal> }<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> // check if new data set being requested is 'none'<o:p></o:p></p><p class=MsoNormal> if(newSourceData == 'none'){ return; }<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> // setup a save strategy and symbology<o:p></o:p></p><p class=MsoNormal> saveStrategy = new OpenLayers.Strategy.Save();<o:p></o:p></p><p class=MsoNormal> saveStrategy.events.register('success', null, saveSuccess);<o:p></o:p></p><p class=MsoNormal> saveStrategy.events.register('fail', null, saveFail); <o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> // setup symbology if not already setup<o:p></o:p></p><p class=MsoNormal> if(!loadedMarkupSymbolizers){ loadedMarkupSymbology(); }<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> // create the imported markup layer<o:p></o:p></p><p class=MsoNormal> markupLayerLoaded = new OpenLayers.Layer.Vector("LoadedLayer", <o:p></o:p></p><p class=MsoNormal> {<o:p></o:p></p><p class=MsoNormal> eventListeners: { "featuresadded": dataLoaded },<o:p></o:p></p><p class=MsoNormal> strategies: <o:p></o:p></p><p class=MsoNormal> [<o:p></o:p></p><p class=MsoNormal> new OpenLayers.Strategy.Fixed(),<o:p></o:p></p><p class=MsoNormal> saveStrategy<o:p></o:p></p><p class=MsoNormal> ], <o:p></o:p></p><p class=MsoNormal> protocol: new OpenLayers.Protocol.HTTP<o:p></o:p></p><p class=MsoNormal> ({<o:p></o:p></p><p class=MsoNormal> url: newSourceData, <o:p></o:p></p><p class=MsoNormal> format: new OpenLayers.Format.GeoJSON<o:p></o:p></p><p class=MsoNormal> ({<o:p></o:p></p><p class=MsoNormal> //ignoreExtraDims: true, <o:p></o:p></p><p class=MsoNormal> internalProjection: P900913,<o:p></o:p></p><p class=MsoNormal> externalProjection: P4326<o:p></o:p></p><p class=MsoNormal> })<o:p></o:p></p><p class=MsoNormal> }),<o:p></o:p></p><p class=MsoNormal> styleMap: loadedMarkupSymbolizers <o:p></o:p></p><p class=MsoNormal> });<o:p></o:p></p><p class=MsoNormal> map.addLayer(markupLayerLoaded);<o:p></o:p></p><p class=MsoNormal>}<o:p></o:p></p><p class=MsoNormal><i><o:p> </o:p></i></p><p class=MsoNormal>function dataLoaded(event) <o:p></o:p></p><p class=MsoNormal>{ this.map.zoomToExtent(event.object.getDataExtent()); }<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>function saveSuccess(event) <o:p></o:p></p><p class=MsoNormal>{ alert('Changes saved');}<o:p></o:p></p><p class=MsoNormal>function saveFail(event) <o:p></o:p></p><p class=MsoNormal>{ alert('Error! Changes not saved');}<o:p></o:p></p></div></body></html>