Database Reference
In-Depth Information
empty
controls
arrayanddeclarethatthemaphasaSphericalMercator's
projection, as shown in the following code:
<script defer="defer" type="text/
javascript">
// instantiate the map object
var map = new OpenLayers.Map("map", {
controls: [],
projection: new
OpenLayers.Projection("EPSG:900913")
});
</script>
4. Right after the
map
variable is declared, add some OpenLayers controls to
the map. For the Web GIS viewer you are creating, you will add the
Nav-
igation
control(whichhandlesmapbrowsingwithmouseevents,suchas
dragging, double-clicking, and scrolling the wheel),
PanZoomBar
control (a
four-direction navigation using the arrows present above the zooming ver-
tical slider), the
LayerSwitcher
control (which handles the switching on
andoffoflayersaddedtothemap),andthe
MousePosition
control(which
displays the map coordinates as they change while the user is moving the
mouse), using the following code:
// add some controls on the map
map.addControl(new
OpenLayers.Control.Navigation());
map.addControl(new
OpenLayers.Control.PanZoomBar()),
map.addControl(new
OpenLayers.Control.LayerSwitcher(
{"div":OpenLayers.Util.getElement("layerswitcher")}));
map.addControl(new
OpenLayers.Control.MousePosition());
5. Now,createtwoGooglebaselayers:oneforGoogleHybridandtheotherfor
Google Terrain Base maps, using the following code:
