[OpenLayers-Users] transform help please

Thu Nov 19 14:01:58 EST 2009

It looks like you are trying to re-project Google raster layers?

I thought OpenLayers was only capable of re-projecting vector layers?

For example, the following article uses OpenLayers (& Proj4JS) to re-project
KML and GeoRSS data (geographic coords, WGS84) to a number of different
projections (Mollweide, Behrmann, etc):

http://www.geowebguru.com/articles/209-how-to-create-an-online-map-with-a-non-mercator-projection-part-2

Richard Marsden
Winwaed Software Technology LLC
http://www.winwaed.com
http://www.mapping-tools.com
http://www.geowebguruc.om

On Thu, Nov 19, 2009 at 12:12 PM, Dash <jimlug at co.clackamas.or.us> wrote:

>
> Aloha Thursday folks,
>
> I am banging my head against the problem for the last several hours.  I
> have
> went through numerous examples and utilized OpenLayers tutorial on
> reprojecting points without any success.  I've even used the Proj4js Wiki
> without any help.  Could some please shed some light on what I am doing
> wrong?
>
> Here is the scenario.  I am trying to transform some coordinates from
> EPSG:2913 to EPSG:900913.  I've also tried a simplified version using
> EPSG:4326 -> EPSG:900913.  Anyway, the transform is not happening for some
> odd reason.  I do have the proj4js library within my code and I have added
> EPSG definition to my /proj4js/lib/def directory.  I am checking if the
> projection by using the getUnits function of the projection class within
> OpenLayers.  If the units come back null, then the proj4js library is
> unavailable.  Why is this?  I'm so confused.  This should be rather
> straight
> forward.  Anyway, here is some of my code.  Hopefully someone can help me
> out.  Thanks.
>
> <head>
> <script src="http://openlayers.org/dev/lib/OpenLayers.js"
> type="text/javascript"></script>
> <script src="./proj4js/lib/proj4js.js"></script>
> <script src="proj4js/lib/defs/EPSG2913.js"></script>
> <script src="proj4js/lib/defs/EPSG900913.js"></script>
> <script src="proj4js/lib/defs/EPSG4326.js"></script>
> </head>
>
> <script type="text/javascript">
> var map;
> function init(){
>        var options = {
>                //projection: new OpenLayers.Projection("EPSG:900913"),
>     // Map projection
>                projection: "EPSG:900913",
>                displayProjection: new OpenLayers.Projection("EPSG:4326"),
>    // Display
> projection
>                units: "m",
>                numZoomLevels: 5,
>                maxResolution: 156543.0339,
>        maxExtent: new OpenLayers.Bounds(-13698618.8209569, 5595988.4768255,
> -13521569.8682338, 5701506.49106001)
>        };
>
>        // Initiate Map Controls
>        map.addControl(new OpenLayers.Control.LayerSwitcher());
>        map.addControl(new OpenLayers.Control.MousePosition());
>
>        // Create Google Mercator Layers
>        var gmap = new OpenLayers.Layer.Google("Google
> Streets",{'sphericalMercator': true, numZoomLevels: 20});
>        var gphy = new OpenLayers.Layer.Google("Google Physical",
> {'sphericalMercator': true, type: G_PHYSICAL_MAP, numZoomLevels: 20});
>    var gsat = new OpenLayers.Layer.Google("Google
> Satellite",{'sphericalMercator': true, type: G_SATELLITE_MAP,
> numZoomLevels:
> 20});
>    var ghyb = new OpenLayers.Layer.Google("Google
> Hybrid",{'sphericalMercator': true, type: G_HYBRID_MAP, numZoomLevels:
> 20});
>
> map.addLayers([gmap, gphy, gsat, ghyb]);
>
> var srcProj = new OpenLayers.Projection("EPSG:4326");
> alert(srcProj.getUnits());
> var point = new OpenLayers.LonLat(-71, 42);
> point.transform(srcProj, map.getProjectionObject());
>
> if(point.transformed)
>        {
>                alert("point already transformed");
>        }
>
> Proj4js.transform(srcProj, map.getProjectionObject(), point);
>
> Any suggestions would be greatly appreciated.  THANKS...
> --
> View this message in context:
> http://n2.nabble.com/transform-help-please-tp4033462p4033462.html
> Sent from the OpenLayers Users mailing list archive at Nabble.com.
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