function MapTypeToLetter(mapType) {
	switch(mapType) {
		case G_NORMAL_MAP	: return'M';
		case G_SATELLITE_MAP	: return'S';
		case G_HYBRID_MAP	: return'H';
		case WMS_NEXRAD_MAP	: return'N';
		default			: return'-';
	}
}

function LetterToMapType(letter) {
	switch(letter) {
		case'M'	: return G_NORMAL_MAP;
		case'S'	: return G_SATELLITE_MAP;
		case'H'	: return G_HYBRID_MAP;
		case'N'	: return WMS_NEXRAD_MAP;
		default	: return G_NORMAL_MAP;
	}
}

function WMSCreateMap(name,copyright,baseUrl,layer,format,transparent,opacity,minResolution,maxResolution,extraTileLayers,urlArg) {
	var tileLayer		= new GTileLayer(new GCopyrightCollection(copyright),minResolution,maxResolution);
	tileLayer.baseUrl	= baseUrl;
	tileLayer.layer		= layer;
	tileLayer.format	= format;
	tileLayer.transparent	= transparent;
	tileLayer.getTileUrl	= WMSGetTileUrl;
	tileLayer.getOpacity	= function() { return opacity; };
	tileLayer.getCopyright	= function() { return {prefix:'',copyrightTexts:[copyright]}; };
	
	var tileLayers		= [];
	for(var i in extraTileLayers) 
		tileLayers.push(extraTileLayers[i]);
		
	tileLayers.push(tileLayer);
	return new GMapType(tileLayers,G_SATELLITE_MAP.getProjection(),name,{errorMessage:_mMapError,urlArg:'o'});
}

function WMSGetTileUrl(tile,zoom) {
	var southWestPixel	= new GPoint(tile.x*256,(tile.y+1)*256);
	var northEastPixel	= new GPoint((tile.x+1)*256,tile.y*256);
	var southWestCoords	= G_NORMAL_MAP.getProjection().fromPixelToLatLng(southWestPixel,zoom);
	var northEastCoords	= G_NORMAL_MAP.getProjection().fromPixelToLatLng(northEastPixel,zoom);
	var bbox		= southWestCoords.lng()+','+southWestCoords.lat()+','+northEastCoords.lng()+','+northEastCoords.lat();
	var transparency	= this.transparent?'&TRANSPARENT=TRUE':'';
	
	return this.baseUrl+'?VERSION=1.1.1&REQUEST=GetMap&LAYERS='+this.layer+'&STYLES=&SRS=EPSG:4326&BBOX='+bbox+'&WIDTH=256&HEIGHT=256&FORMAT='+this.format+'&BGCOLOR=0xCCCCCC&EXCEPTIONS=INIMAGE'+transparency;
}

var WMS_NEXRAD_MAP	= WMSCreateMap('RADAR','NWS/Iowa U. Ag. Dept.','http://mesonet.agron.iastate.edu/cgi-bin/wms/nexrad/n0r.cgi','nexrad-n0r','image/png',true,0.666,4,10,G_NORMAL_MAP.getTileLayers(),'n');