Hi everyone, I'm working on my first OpenLayers map and I'm having a problem with toggling layer visibility. I want to use an HTML form with radiobuttons to toggle the layers instead of the LayerSwitcher control. When I choose a layer other than the first layer in the list, it draws fine once but if you do any zooming or panning it will not redraw. If you choose the first layer, it works fine. Here's the map:
http://maps.massgis.state.ma.us/dcr/forestry09.html The function that chooses the new layer is called changeSymbolization (it's called by the radiobuttons' change event). It loops through the layers and makes all but one invisible. function changeSymbolization(byField){ var byFieldSplit = byField.toString().split(','); lz = map.layers; for (n=0; n < lz.length; n++) { lz[n].setVisibility(lz[n].name == byFieldSplit[0]); } document.getElementById("theLegendTitle").innerHTML = byFieldSplit[1]; document.getElementById("theLegend").src = "http://giswebservices.massgis.state.ma.us/geoserver/wms?VERSION=1.1.0&R EQUEST=GetLegendGraphic&LAYER=massgis:DCR.TOWNS_POLYM_FORESTRY&STYLE=DCR .TOWNS_POLYM_FORESTRY::" + byFieldSplit[0] + "&WIDTH=16&HEIGHT=16&FORMAT=image/png"; } [this function is called by radiobuttons, for example]: <input type="radio" name="chosenSymbology" onclick="changeSymbolization(this.value)" value="FSCARS_SC,Towns symbolized by<br/>National Forest Service<br/>CARS Score:" /> Federal CARS score<br /> After trying a few approaches, I set it up so there are 17 different layers added to the map, each of which contains all the background layers plus the foreground layer (which is symbolized by a different attribute in each layer). This is done in the init() function. I'm not sure this is the best way to do it, but when I tried having the background and foreground layers in separate layers, the foreground layer would block the background layers by drawing a white background on the whole map before drawing the foreground layer. [Here is what each layer looks like (there are 17 of these, each with a different name and different Style for one of the layers)]: IMPERV_PCT_Layer = new OpenLayers.Layer.WMS( "IMPERV_PCT", "http://giswebservices.massgis.state.ma.us/geoserver/wms";, { width: '600', srs: 'EPSG:26986', layers: 'massgis:DCR.TOWNS_POLYM_FORESTRY,massgis:GISDATA.OCEANMASK_POLY,massgis :GISDATA.NEMASK_POLY,massgis:DCR.TOWNS_POLYM_FORESTRY,massgis:GISDATA.TO WNS_POLY', height: '358', styles: ',,GISDATA.NEMASK_POLY::Light_Yellow,DCR.TOWNS_POLYM_FORESTRY::IMPERV_PC T,GISDATA.TOWNS_POLY::Labels_Med', format: 'image/png' }, {singleTile: true, ratio: 1} ); IMPERV_PCT_Layer.setVisibility(0); [Here is how they're added to the map]: map.addLayers([SUSTCOM_SC_Layer,FSCARS_SC_Layer,ST_ASST_YN_Layer,MGTPLAN _YN_Layer,ADV_GRP_YN_Layer,LOC_ORD_YN_Layer,PROSTAF_YN_Layer,TREEINV_YN_ Layer,TREECITYYN_Layer,OSPLAN_YN_Layer,PDENSQMI00_Layer,BUDGET_P_C_Layer ,UFORE_YN_Layer,STRATUM_YN_Layer,UCF_INDEX_Layer,CANOPY_COV_Layer,IMPERV _PCT_Layer]); I tried to find a similar example somewhere, but they seem to use the layerswitcher control and be really simple (Examples) or be so complex that I couldn't make heads of tails of them (Gallery). Does anyone have a suggestion for how to fix the redrawing problem, or a better approach to dealing with the layer switching that would solve the problem? Thank you for your help! --David _______________________________________________ Users mailing list [email protected] http://openlayers.org/mailman/listinfo/users
