[OpenLayers-Users] Re: marker can be created from feature?

[IvanBell]

I am not sure of the "right way", as I am still learning best practices. 
However, the following is how I add a marker to my maps.


I first tried creating a new marker feature (e.g., new
OpenLayers.Feature(layer,lonlat)) and calling the addMarker() method on the
layer.  However, I could not get that to work.  It appears that the
addMarker() method is not supported on a vector layer.


I now define a marker layer, which has a style map that defines the marker's
style.




      m_oMarkerLayer = new OpenLayers.Layer.Vector(
           "Marker Layer",
           {
              styleMap: new OpenLayers.StyleMap({
                                                  //
                                                  // Shift graphic up 25
pixels
                                                  //
                                                  graphicYOffset: -21,

                                                  //
                                                  // This will put a label
beneath the icon.  If the icon cannot be found, or does
                                                  // not exist, then only
the label will be displayed.
                                                  //
                                                  // label: "Some Label",

                                                  //
                                                  // Set the external
graphic and background graphic images.
                                                  //
                                                  externalGraphic:
"http://localhost:8081/geoserver/openlayers/img/marker.png",
                                                  backgroundGraphic:
"http://localhost:8081/geoserver/openlayers/img/marker_shadow.png",

                                                  //
                                                  // Makes sure the
background graphic is placed correctly relative
                                                  // to the external
graphic.
                                                  //
                                                  backgroundXOffset: 0,
                                                  backgroundYOffset: -16,

                                                  //
                                                  // Set the z-indexes of
both graphics to make sure the background
                                                  // graphics stay in the
background (shadows on top of markers looks
                                                  // odd; let's not do
that).
                                                  //
                                                  graphicZIndex:
MARKER_Z_INDEX,
                                                  backgroundGraphicZIndex:
SHADOW_Z_INDEX,
                                                  pointRadius: 10
                                              }),
              displayInLayerSwitcher: false,
              isBaseLayer: false,
              rendererOptions: { yOrdering: true }
           }
      );



I also define a method to add a marker to the map.  This is called from a
click event in my map.




      /**
       * Create marker.
       */
      function addMarker( p_oLongitudeLatitude ) {
         //
         // converts the LonLat coordinates to Pixel format
         //
         var oPixelPoint = m_oMap.getPixelFromLonLat( p_oLongitudeLatitude
);

         //
         // Add the marker to the markers layer.
         //
         arrFeatures = [];
         oMarker = new OpenLayers.Feature.Vector( new
OpenLayers.Geometry.Point( p_oLongitudeLatitude.lon,
p_oLongitudeLatitude.lat ) );
         arrFeatures.push( oMarker );
         m_oMarkerLayer.addFeatures( arrFeatures );
         m_oMarkerLayer.redraw();
      }



All of this code was derived directly from the 
http://dev.openlayers.org/releases/OpenLayers-2.10/examples/ OpenLayers
examples .


Sincerely,

Ivan



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