求助ogc NWMTSLayer加载加载瓦片怎么设置zoom

[亲努力啊]

                      var extent = new NBounds(108.187401576852,28.1978827797115,116.377025347457,33.7230181778446);

			var resolutions = [0.01098632812500002,0.00549316406250001,0.0027465820312500017,0.0013732910156250009,0.000686645507812499,0.0003433227539062495,0.00017166137695312503,0.00008583068847656251,0.000042915344238281406,0.000021457672119140645,0.000010728836059570307,0.000005364418029785169,0.000002682210361715995,0.0000013411051808579975];
			var map = new NMap(mapDivId , {units: 'dd', projection:'epsg:4490'}); 
			map.zoomLevelsCount = 6;
			map.limitedZoomExtent = extent;
			map.maxResolution = 180/256;
			var mapLayer = new NWMTSLayer(
				'Vector',
				'http://xxxx:8877/newmap/ogc/Vector/wmts/Vector/Default/epsg:4490/',
				{isBasicLayer:true,tileOrigin:new NLatLng(-180,90),format:'image/png',resolutions:resolutions}
				
			);
			map.addLayer(mapLayer);
			map.zoomToMaxExtent();
			map.zoomToExtent(extent);
			return map;

加载出来的载瓦地址是 http://xxxxx/15/5421/26842.png
实际是http://xxxxx/8/5421/26842.png这样才是正确的
请问怎么设置zoom才能加载正常