Tag Archives: tiled WMS overlay

Tiled WMS overlay in Windows Phone 7

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  Update 13/03/2013, here is new  blog about Tiled WMS overlay for Windows Phone 8 :https://blog.sumbera.com/2013/03/10/tiled-wms-overlay-in-windows-phone-8/

This post [https://blog.sumbera.com/2010/02/25/overlay-wms-on- google-in-silverlight-bing/ ] talked about how to overlay over the Bing maps Silverlight control Google tiles  and tiled WMS. It was quite easy to port this web sample into the Windows Phone 7 emulator. I took a smaple code from Training kit called “Ex1-TheBingMapControl” and extend it with the 2 classes : GoogleTile and WmsTile, with slight changes to the namespace using Microsoft.Phone.Controls.Maps (original for Silverlight was  Microsoft.Maps.MapControl). Then extend MainPage.XAML with :

                    <my:MapTileLayer Opacity=”1″>
                        <my:MapTileLayer.TileSources>
                            <local:GoogleTile></local:GoogleTile>
                        </my:MapTileLayer.TileSources>
                    </my:MapTileLayer>
                    <my:MapTileLayer Opacity=”1″>
                        <my:MapTileLayer.TileSources>
                            <local:WMSTiledOverlay></local:WMSTiledOverlay>
                        </my:MapTileLayer.TileSources>
                    </my:MapTileLayer>
 
 

Extended sample code availabel for download here : http://www.sumbera.com/lab/wp7/TheBingMapControlWithWMSandGoogle.zip

Update: I found the way calculating BoundingBox from the quadkey somehow limiting (the DeepEarth weay) since it worked only till the level 18. So here is updated class fro getting correct bounding box of the tiled WMS request in the Bing Silverlight control:

            public static double TileToWorldPosX(double tile_x, int zoom) {
return  (float)((tile_x / Math.Pow(2.0, zoom) * 360.0) – 180.0);
}
public static double TileToWorldPosY( double tile_y, int zoom) {
double n = Math.PI – ((2.0 * Math.PI * tile_y) / Math.Pow(2.0, zoom));
return   (float)(180.0 / Math.PI * Math.Atan(Math.Sinh(n)));
}
public override Uri GetUri(int tilePositionX, int tilePositionY, int tileLevel) {
                int zoom = tileLevel; //SSU tileLevel would be same as zoom in Bing control
double deltaX = 0;// 0.00135; //SSU deltaX for SLP WMS
double deltaY = 0;// 0.00058; //SSU deltaY for SLP WMS
double minXLon = TileToWorldPosX(tilePositionX, zoom) + deltaX;
double minYLat = TileToWorldPosY(tilePositionY + 1, zoom) + deltaY;
double maxXLon = TileToWorldPosX(tilePositionX + 1, zoom) + deltaX;
double maxYLat = TileToWorldPosY(tilePositionY, zoom) + deltaY;
string wmsUrl = string.Format(this.UriFormat, minXLon, minYLat, maxXLon, maxYLat, 256);
return new Uri(wmsUrl);
}}
   

 

Tiled WMS overlay on Google Map v3

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this is the third sample of the tiled WMS overlay over the Spherical Mercator, this time over the new Google Map v3. Previsous post talked about overlyaing WMS in  Silverlight Bing maps (https://blog.sumbera.com/2010/02/25/overlay-wms-on-google-in-silverlight-bing/ ) and OpenLayers (https://blog.sumbera.com/2010/02/17/overlay-wms-on-google-in-openlayers/).

Sample application can be found here: http://www.sumbera.com/lab/GoogleV3/tiledWMSoverlayGoogleV3.htm You can try to run it on your mobile device as well – suprisingly it run very well on my iPhone (sometimes it just crash Safari :), however on the iPad there are some more serious issues that will be hopefuly resolved with new iOS update (JavaScript stops to run).

For the new Google Map v3 you have to do the following :

//Define custom WMS tiled layer

var SLPLayer = 
 new google.maps.ImageMapType (
 {
  getTileUrl:
    function (coord, zoom) { 
      var proj = map.getProjection(); 
      var zfactor = Math.pow(2, zoom); 
       // get Long Lat coordinates
      var top = proj.fromPointToLatLng(
             new google.maps.Point(coord.x * 256 / zfactor, coord.y * 256 / zfactor) ); 
      var bot = proj.fromPointToLatLng(
            new google.maps.Point((coord.x + 1) * 256 / zfactor, (coord.y + 1) * 256 / zfactor)); 
      //corrections for the slight shift of the SLP (mapserver)
       var deltaX = 0.0013; 
       var deltaY = 0.00058; 
      
      //create the Bounding box string
       var bbox = (top.lng() + deltaX) + "," +(bot.lat() + deltaY) +","
                           +(bot.lng() + deltaX) +"," +(top.lat() + deltaY);
      
       //base WMS URL
        var url = 
       "http://mapserver-slp.mendelu.cz/cgi-bin/mapserv?map=/var/local/slp/krtinyWMS.map&" ;
       url +="&REQUEST=GetMap"; //WMS operation
       url +="&SERVICE=WMS"; //WMS service
       url +="&VERSION=1.1.1"; //WMS version 
       url +="&LAYERS=" + "typologie,hm2003"; //WMS layers
       url +="&FORMAT=image/png"; //WMS format
       url +="&BGCOLOR=0xFFFFFF" ;
       url +="&TRANSPARENT=TRUE" ;
       url +="&SRS=EPSG:4326"; //set WGS84 
       url +="&BBOX="+ bbox; // set bounding box
       url +="&WIDTH=256"; //tile size in google
       url +="&HEIGHT=256" ; 
       return url; // return URL for the tile    
     }, //getTileURL
 tileSize: new google.maps.Size(256, 256),
 isPng: true
 });

//add WMS layer
 map.overlayMapTypes.push(SLPLayer); 

 
 
 

Overlay WMS on Google in OpenLayers

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[Note: therea are related post: overlyaing tiled WMS over the new Google Map v3 https://blog.sumbera.com/2010/11/02/tiled-wms-overlay-on-google-map-v3/ and overlying tiled WMS over the Silverlight Bing map https://blog.sumbera.com/2010/02/25/overlay-wms-on-google-in-silverlight-bing/ ]

Is it possible to display WMS (EPSG:4326) over the Google (EPSG:900913) in Openlayers ? Yes ! thanks to the great img ‘feature’ that enables you to shrink/expand your return image based on defined image size. That means that if your map view is rectangular or you request WMS as tiles (rectangular too) you get proper overlay of EPSG:4326 on EPSG:900913) . Example of various image sizes follows (these are actually WMS GetMap requests):

256 x 160

256 x 256

Here is the way how to implement it in OpenLayers – very simplified:

1. read this post http://docs.openlayers.org/library/spherical_mercator.html and create your Google map:

var options = {
projection: new OpenLayers.Projection(“EPSG:900913”),
displayProjection: new OpenLayers.Projection(“EPSG:4326”),
units: “m”,
numZoomLevels: 22,
maxExtent: new OpenLayers.Bounds(-20037508, -20037508,
20037508, 20037508.34)
};
map = new OpenLayers.Map(‘map’, options);
            // create Google Mercator layers
            var ghyb = new OpenLayers.Layer.Google(
“Google Hybrid”,
{ type: G_HYBRID_MAP, ‘sphericalMercator’: true }
);

2. add your WMS layer

var gwms = new OpenLayers.Layer.TMS(“SLP”, “http://mapserver-slp.mendelu.cz/cgi-bin/mapserv?map=/var/local/slp/krtinyWMS.map&”,
{
layers: ‘obrys,typologie,hm2003’,
type: ‘png’,
visibility: true,
getURL: get_wms_url,
format: “image/png”,
opacity: 1,
isBaseLayer: false,
deltaX: 0.0013,
deltaY: 0.00058
});

3. include support for reprojection before you include OpenLayers:

<script src =”proj4js/lib/proj4js-combined.js”>script>

4. handle WMS as TMS tiles as this:

function get_wms_url(bounds) {

// recalculate bounds from Google to WGS
var proj = new OpenLayers.Projection(“EPSG:4326”);
bounds.transform(map.getProjectionObject(), proj);

// this is not necessary for most servers display overlay correctly,
//but in my case the WMS  has been slightly shifted, so I had to correct this with this delta shift

bounds.left += this.deltaX;
bounds.right += this.deltaX;
bounds.top += this.deltaY;
bounds.bottom += this.deltaY;

            //construct WMS request

var url = this.url;
url += “&REQUEST=GetMap”;
url += “&SERVICE=WMS”;
url += “&VERSION=1.1.1”;
url += “&LAYERS=” + this.layers;
url += “&FORMAT=” + this.format;
url += “&TRANSPARENT=TRUE”;
url += “&SRS=” + “EPSG:4326”;
url += “&BBOX=” + bounds.toBBOX();
url += “&WIDTH=” + this.tileSize.w;
url += “&HEIGHT=” + this.tileSize.h;
return url;

}

That is, live example you can see here http://www.sumbera.com/lab/wms/getcapWGS.htm

or in MapShake here : http://www.mapshake.cz/mapfs.aspx?i=464