/*
 * Create GoogleMap WMS (transparent) layers on any GoogleMap.
 *
 * Just van den Broecke - just AT justobjects.nl - www.justobjects.nl - www.geoskating.com
 * version: $Id: GMap.js 201 2006-11-25 11:59:49Z just $
 *
 * This (experimental) code can be downloaded from
 * http://www.geotracing.com/gt/script/gmap.js
 *
 * CREDITS
 * This code is based on and inspired by:
 * Brian Flood - http://www.spatialdatalogic.com/cs/blogs/brian_flood/archive/2005/07/11/39.aspx and
 * Kyle Mulka - http://blog.kylemulka.com/?p=287
 * I have merely merged the two approaches taken by each of these great minds !
 *
 * EXAMPLE
 *   // Fake WMS server to be used for overlaying map with transparent GIF
 *   // Use a real WMS server here.
 *   var WMS_URL_ROUTE='http://www.geoskating.com/gmap/route-wms.jsp?';
 *
 *   // Create WMSSpec
 *   // need: wmsURL, gName, gShortName, wmsLayers, wmsStyles, wmsFormat, [wmsVersion], [wmsBgColor], [wmsSrs]
 *   var G_MAP_WMS_SPEC = createWMSSpec(WMS_URL_ROUTE, "MyWMS", "MyWMS", "routes", "default", "image/gif", "1.0.0");
 *
 *   // Use WMSSpec to create transparent overlay on a standard Google MapSpec
 *   var G_MAP_WMS_OVERLAY_SPEC = createWMSOverlaySpec(G_SATELLITE_TYPE, G_MAP_WMS_SPEC, "MyOvWMS", "MyOvWMS");
 *
 *   // Setup the map
 *   var map = new GMap2(document.getElementById("map"));
 *   // Create mapspecs array
 *	 map.addMapType(G_MAP_TYPE);
 *	 map.addMapType(G_SATELLITE_TYPE);
 * 	 map.addMapType(G_MAP_WMS_SPEC);
 *	 map.addMapType(G_MAP_WMS_OVERLAY_SPEC);
 *   map.addControl(new GMapTypeControl());
 *   map.setCenter(new GLatLon(52.35, 4.9), 10, G_MAP_WMS_OVERLAY_SPEC);
 */



/*
Call generic wms service for GoogleMaps v2
John Deck, UC Berkeley
Inspiration & Code from:
	Mike Williams http://www.econym.demon.co.uk/googlemaps2/ V2 Reference & custommap code
	Brian Flood http://www.spatialdatalogic.com/cs/blogs/brian_flood/archive/2005/07/11/39.aspx V1 WMS code
	Kyle Mulka http://blog.kylemulka.com/?p=287  V1 WMS code modifications
	http://search.cpan.org/src/RRWO/GPS-Lowrance-0.31/lib/Geo/Coordinates/MercatorMeters.pm
*/

var MAGIC_NUMBER = 6356752.3142;
var DEG2RAD = 0.0174532922519943;
var PI = 3.14159267;
function dd2MercMetersLng(p_lng) {
	return MAGIC_NUMBER * (p_lng * DEG2RAD);
}

function dd2MercMetersLat(p_lat) {
	if (p_lat >= 85) p_lat = 85;
	if (p_lat <= -85) p_lat = -85;
	return MAGIC_NUMBER * Math.log(Math.tan(((p_lat * DEG2RAD) + (PI / 2)) / 2));
}

CustomGetTileUrl = function(a, b, c) {
	if (typeof(window['this.myMercZoomLevel']) == "undefined") this.myMercZoomLevel = 0;
	if (typeof(window['this.myStyles']) == "undefined") this.myStyles = "";
	var lULP = new GPoint(a.x * 256, (a.y + 1) * 256);
	var lLRP = new GPoint((a.x + 1) * 256, a.y * 256);
	var lUL = G_NORMAL_MAP.getProjection().fromPixelToLatLng(lULP, b, c);
	var lLR = G_NORMAL_MAP.getProjection().fromPixelToLatLng(lLRP, b, c);
	// switch between Mercator and DD if merczoomlevel is set
	if (this.myMercZoomLevel != 0 && map.getZoom() < this.myMercZoomLevel) {
		var lBbox = dd2MercMetersLng(lUL.lngDegrees) + "," + dd2MercMetersLat(lUL.latDegrees) + "," + dd2MercMetersLng(lLR.lngDegrees) + "," + dd2MercMetersLat(lLR.latDegrees);
		var lSRS = "EPSG:54004";
	} else {
		var lBbox = lUL.x + "," + lUL.y + "," + lLR.x + "," + lLR.y;
		var lSRS = "EPSG:4326";
	}
	var lURL = this.myBaseURL;
	lURL += "&REQUEST=GetMap";
	lURL += "&SERVICE=WMS";
	lURL += "&VERSION=" + this.myVersion;
	lURL += "&LAYERS=" + this.myLayers;
	lURL += "&STYLES=" + this.myStyles;
	lURL += "&FORMAT=" + this.myFormat;
	lURL += "&BGCOLOR=" + this.myBgColor;
	lURL += "&TRANSPARENT=TRUE";
	lURL += "&SRS=" + lSRS;
	lURL += "&BBOX=" + lBbox;
	lURL += "&WIDTH=256";
	lURL += "&HEIGHT=256";
	lURL += "&reaspect=false";
	return lURL;
}


/*
See http://chignik.berkeley.edu/google/wmstest236.html
var map = new GMap(document.getElementById("map"));

// Create tile layers
var tileCountry = new GTileLayer(new GCopyrightCollection(""), 1, 17);
tileCountry.myLayers = 'country';
tileCountry.myFormat = 'image/gif';
tileCountry.myBaseURL = 'http://chignik.berkeley.edu/cgi-bin/mapserv440?map=/usr/local/web/html/google/wms.map&';
tileCountry.getTileUrl = CustomGetTileUrl;
//tileCountry.getOpacity = function() {return 0.5;}

var tileCounty = new GTileLayer(new GCopyrightCollection(""), 1, 17);
tileCounty.myLayers = 'us_county';
tileCounty.myFormat = 'image/gif';
tileCounty.myBaseURL = 'http://chignik.berkeley.edu/cgi-bin/mapserv440?map=/usr/local/web/html/google/wms.map&';
tileCounty.getTileUrl = CustomGetTileUrl;
//tileCounty.getOpacity = function() {return 0.5;}

var tileDoq = new GTileLayer(new GCopyrightCollection(""), 1, 17);
tileDoq.myLayers = 'doq';
tileDoq.myFormat = 'image/jpeg';
tileDoq.myBaseURL = 'http://terraservice.net/ogcmap.ashx?';
tileDoq.getTileUrl = CustomGetTileUrl;

var layer1 = [tileDoq,tileCounty];
var layer2 = [tileCountry,tileCounty];
var layer3 = [G_SATELLITE_MAP.getTileLayers()[0],G_HYBRID_MAP.getTileLayers()[1],tileCounty];

var custommap1 = new GMapType(layer1, G_SATELLITE_MAP.getProjection(), "WMS 3", G_SATELLITE_MAP);
var custommap2 = new GMapType(layer2, G_SATELLITE_MAP.getProjection(), "WMS 2", G_SATELLITE_MAP);
var custommap3 = new GMapType(layer3, G_SATELLITE_MAP.getProjection(), "WMS 1", G_SATELLITE_MAP);

map.getMapTypes().length = 0;
map.addMapType(custommap3);
map.addMapType(custommap2);
map.addMapType(custommap1);

map.setCenter(new GLatLng(37.8, -122.4819), 11);
map.addControl(new GLargeMapControl());
map.addControl(new GMapTypeControl());

// Test adding a polyline (this caused problems in previous version of code)
var pointArray = new Array(0);
pointArray.push(new GLatLng(37.81, -122.48));
pointArray.push(new GLatLng(37.81, -122.4));
pointArray.push(new GLatLng(37.89, -122.4));
pointArray.push(new GLatLng(37.89, -122.48));
pointArray.push(new GLatLng(37.81, -122.48));
var pl = new GPolyline(pointArray, '#ff00ff', 5, .5);
map.addOverlay(pl);
*/

/** Create WMS type spec as a GMap Spec. */
function createWMSSpec(wmsURL, gName, gShortName, wmsLayers, wmsStyles, wmsFormat, wmsVersion, wmsBgColor, wmsSrs) {
	var tile = new GTileLayer(new GCopyrightCollection(""), 1, 17);
	tile.myLayers = wmsLayers;
	tile.myStyles = (wmsStyles ? wmsStyles : "");
	;
	tile.myFormat = (wmsFormat ? wmsFormat : "image/gif");
	;
	tile.myVersion = (wmsVersion ? wmsVersion : "1.1.1");
	tile.myBgColor = (wmsBgColor ? wmsBgColor : "0xFFFFFF");
	tile.myBaseURL = wmsURL;
	tile.getTileUrl = CustomGetTileUrl;
	//tileCounty.getOpacity = function() {return 0.5;}


	var layer = [tile];

	var mapType = new GMapType(layer, G_SATELLITE_MAP.getProjection(), gName, G_SATELLITE_MAP);

	return mapType;
}

/** Create transparent WMS overlay layer on standard GMap Spec. */
function createWMSOverlaySpec(gSpec, wmsSpec, gName, gShortName) {
	wmsSpec.getTileLayers()[0].getOpacity = function() {
		return 1.0;
	}
	var layers = [gSpec.getTileLayers()[0], wmsSpec.getTileLayers()[0]];
	return new GMapType(layers, gSpec.getProjection(), gShortName);

}