Add Identify Capabilities

The following adds identifying capabilities to your application. On mouse click on a property the property will be outlined. To get a handle to the APN on identify look at the IdentifyObserver success method.

function load() 
{
    if (GBrowserIsCompatible()) {
        map = new GMap2(document.getElementById("map"));
        map.setCenter(new GLatLng(37.4419, -122.1419), 17);
        map.addControl(new GSmallMapControl());
        map.addControl(new GMapTypeControl());
    }
    
    var divObj = document.getElementById("map");
    divObj.onclick = MouseHandler;
}//load

function MouseHandler(event){

    var x, y;
    // for IE
    if (event==null)
    {
	event = window.event;
	x = event.x;
	y = event.y;
    }
    // for Firefox
    else
    {
	x = event.clientX - event.currentTarget.offsetLeft;
	y = event.clientY - event.currentTarget.offsetTop;
    }
	
    // converts screen coordinate to map latitude longitude
    var latLng = map.fromContainerPixelToLatLng(new GPoint(x, y));

    // create query control object and point it to the query api url.
    var queryControl = new DMCQueryControl();

    // create a geometry to use in query.
    var geo = new DMCPoint(latLng.lng(), latLng.lat());
    queryControl.setGeometryFilter(geo);

    // execute query.
    queryControl.execute(new IdentifyObserver(),"success", "failure", "ID");
}

// observer to handle the idenitfy response.
function IdentifyObserver()
{
    this.success = function(recordSet)
    {
	    var record = recordSet.getByIndex(0);
	    if(record != null)
	    {
		    var apn = record.getByName("APN");
		    var fips = record.getByName("FIPS");
		    document.getElementById("output").innerText = "APN:" + apn + " FIPS:" + fips;
		    var geometry = record.getByName("GEOMETRY");
		    drawPolygon(geometry);
	    }
    }

    this.failure = function(err)
    {
	    //alert("Could not identify parcel at this location.");
    }
}

var identifyLayer = null;

// draws the identified shape on the map.
function drawPolygon(dmcPolygon){

    if(map == null || dmcPolygon == null) return;

    if(identifyLayer != null)
	    map.removeOverlay(identifyLayer);

    var color= "#FF0000";
    var weight = 3;
    var opacity = 1;
    var fillColor = "#FF0000";
    var fillOpacity = 0.3;

    identifyLayer = DMCtoGoogGeometry( dmcPolygon, color, weight, opacity, fillColor, fillOpacity);				
    map.addOverlay(identifyLayer);
}

Query on Map Extent

The following example performs a geometry query using the map extent, returning all parcels visible on the map, up to a maximum of 200.

function load() {

    if (GBrowserIsCompatible()) {
        map = new GMap2(document.getElementById("map"));
        map.setCenter(new GLatLng(37.4419, -122.1419), 17);
        map.addControl(newGSmallMapControl());
        map.addControl(new GMapTypeControl());
    }
	
    GEvent.bind(map, "moveend", this, QueryMapExtent);
    QueryMapExtent();

}//load

function QueryMapExtent()
{
    var mapBounds = map.getBounds();
    var sw = mapBounds.getSouthWest();
    var ne = mapBounds.getNorthEast();
	
    var geoPoints = [new DMCPoint(sw.lng(), ne.lat()), new DMCPoint(ne.lng(), ne.lat()), new DMCPoint(ne.lng(), sw.lat()), new DMCPoint(sw.lng(), sw.lat()), new DMCPoint(sw.lng(), ne.lat())];
    var geo = new DMCPolygon(geoPoints);
	
    // create query control object and point it to the query api url.
    var queryControl = new DMCQueryControl();    
    queryControl.setGeometryFilter(geo);
    queryControl.setMaxOutputRecords(200);
	
    //Set the queryControl object to return the centroids of the parcels
    queryControl.setReturnGeometryType(3);
		
    // execute query.
    queryControl.execute(new IdentifyObserver(),"success", "failure", "ID");
    progressBar.style.visibility = "visible";	    
}
	
var identifyLayers = new Array();

// observer to handle the idenitfy response.
function IdentifyObserver()
{
    this.success = function(recordSet)
    {		
        for(var i = 0; i < identifyLayers.length; i++)
            map.removeOverlay(identifyLayers[i]);
        identifyLayers = new Array();
		
        var record;
        var geometry;
		
        var length = recordSet.getCount();
        for(var i = 0; i < length; i++)
        {
            record = recordSet.getByIndex(i);
            if(record != null)
            {			   
                geometry = record.getByName("GEOMETRY");
                drawPoint(geometry);
            }
        }
        progressBar.style.visibility = "hidden";    
    }
	
    this.failure = function(err)
    {
        //alert("Could not identify parcel at this location.");
    }
}

// draws the identified shape on the map.
function drawPoint(dmcPolygon){

    if(map == null || dmcPolygon == null) return;
	
    var identifyLayer = new GMarker(DMCtoGoogGeometry(dmcPolygon));
    identifyLayers.push(identifyLayer);
    map.addOverlay(identifyLayer);
}