Re: [Geotools-gt2-users] define projection when overlaying WMS and shapefile in JMapFrame

[Michael B. <mic...@gm...>]

Hello George,

Firstly, with GeoTools 8 I'd recommend that you use MapContent in your
own code instead of the deprecated MapContext class.

There should be a status bar item (right hand side; you might need to
widen the frame to see it) to show or set the CRS for the display.

Programmatically you can do the same thing:

MapContent map = new MapContent();
// add layers, then...
map.getViewport().setCoordinateReferenceSystem( myDisplayCRS );

See the MapViewport javadocs for more info:
http://docs.geotools.org/latest/javadocs/org/geotools/map/MapViewport.html

Yet another way to do it is:
JMapFrame frame = ...
ReferencedEnvelope bounds = ... // create ReferencedEnvelope with desired CRS
frame.getMapPane().setDisplayArea( bounds );

Hope this helps.

Michael


On 12 July 2012 19:19, George Taylor <geo...@ya...> wrote:
> Hello,
> I am looking for some information how to set the projection correctly for a
> MapContext or JMapFrame, such that all layer overlays are correctly
> displayed. I am running displayWmsAndShapefile() (code below) to display a
> shapefile (110m_coastline.shp from
> http://www.naturalearthdata.com/downloads/110m-physical-vectors/) and the
> "Ocean Coastline" layer from the WMS at
> http://atlas.gc.ca/cgi-bin/atlaswms_en?VERSION=1.1.1&Request=GetCapabilities&Service=WMS.
>
> The result shows that the two layers don't match: http://imagebin.org/220454
> If I show the shapefile alone, the JMapFrame sets the CRS to GCS_WGS_1984.
> If I show the WMS alone, the JMapFrame sets the CRS to EPSG:4326. How can I
> force the JMapFrame to paint everything using EPSG:4326?
>
> More generally, how can I choose the CRS that is requested from a WMS server
> if the server supports several CRSs? Using a GetMapRequest I could use the
> setSRS() method. But in the code below there is no GetMapRequest involved.
> Can I still force the JMapFrame to request the WMS Layer in a different CRS?
>
> Thank you
> George
>
> --- code snippet (using geotools-8.0-RC2) ---
>
>   private void displayWmsAndShapefile() throws Exception {
>                 File sourceFile;
>                 SimpleFeatureSource featureSource;
>                 MapContext map;
>
>         sourceFile = JFileDataStoreChooser.showOpenFile("shp", null);
>         if (sourceFile == null) {
>             return;
>         }
>         FileDataStore store = FileDataStoreFinder.getDataStore(sourceFile);
>         featureSource = store.getFeatureSource();
>
>         // Create a map context and add our shapefile to it
>         map = new DefaultMapContext();
>         map.addLayer(featureSource, null);
>
>         //WMS Stuff:
>         URL capabilitiesURL = WMSChooser.showChooseWMS();
>         if( capabilitiesURL == null ){
>           System.exit(0); // canceled
>         }
>         WebMapServer wms = new WebMapServer( capabilitiesURL );
>
>         List<Layer> wmsLayers = WMSLayerChooser.showSelectLayer( wms );
>         if( wmsLayers == null ){
>           JOptionPane.showMessageDialog(null, "Could not connect - check
> url");
>           System.exit(0);
>         }
>
>         for( Layer wmsLayer : wmsLayers ){
>             WMSMapLayer displayLayer = new WMSMapLayer(wms, wmsLayer );
>             map.addLayer( displayLayer );
>         }
>
>         // Create a JMapFrame with custom toolbar buttons
>         JMapFrame mapFrame = new JMapFrame(map);
>         mapFrame.enableToolBar(true);
>         mapFrame.enableStatusBar(true);
>
>         // Display the map frame. When it is closed the application will
> exit
>         mapFrame.setSize(800, 600);
>         mapFrame.setVisible(true);
>     }
>
>
>
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