[OpenLayers-Dev] Vector layer marker drifting with Google base map

[Eric Lemoine]

Hi Sean. You need to use ESPG:900913 and set sphericalMercator to true
in the options passed to the constructor of the Google layer. There's
a page on OpenLayers' wiki about this, search SphericalMercator using
the wiki's search engine. Cheers. Eric

2008/9/18, Sean Gillies <sgillies at frii.com>:
> Hi all,
>
> I'm trying to overlay a point vector layer symbolized with drop shadow
> markers over a base Google layer. Things look fine, the marker is where
> I expect it, until I pan and then the position of the marker begins to
> drift approximately half height of the marker in the panning direction.
> I'm using the javascript served from openlayers.org/api/OpenLayers.js.
>
> Known bug? Programmer error? Script below:
>
>
> <script type="text/javascript">
>   var map, base, marker, coords;
>   var SHADOW_Z_INDEX = 10;
>   var MARKER_Z_INDEX = 11;
>
>   function init() {
>     map = new OpenLayers.Map('map');
>     base = new OpenLayers.Layer.Google(
>                 "Base", {
>                     isBaseLayer: true,
>                     type: G_PHYSICAL_MAP,
>                     }
>                 );
>     marker = new OpenLayers.Layer.Vector(
>                 "Marker",
>                 {
>                     styleMap: new OpenLayers.StyleMap({
>                         externalGraphic:
> "http://openlayers.org/dev/img/marker-gold.png",
>                         backgroundGraphic:
> "http://openlayers.org/dev/examples/marker_shadow.png",
>                         backgroundXOffset: 0,
>                         backgroundYOffset: -7,
>                         graphicZIndex: MARKER_Z_INDEX,
>                         backgroundGraphicZIndex: SHADOW_Z_INDEX,
>                         pointRadius: 10
>                     }),
>                     reproject: true,
>                     isBaseLayer: false,
>                     projection
>                     rendererOptions: {yOrdering: true}
>                 }
>             );
>     coords = pleiades_oljs.centroid.coordinates;
>     map.addLayers([base, marker]);
>     map.setCenter(new OpenLayers.LonLat(coords[0], coords[1]), 5);
>     marker.features.push(
>                     new OpenLayers.Feature.Vector(
>                         new OpenLayers.Geometry.Point(coords[0], coords[1])
>                     )
>                 );
>   }
> </script>
>
> I'm grateful for any suggestions.
>
> Sean
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