function doLayout(ecModel, payload) {
	        var api = this._api;
	        each(visualFuncs, function (visual) {
	            if (visual.isLayout) {
	                visual.func(ecModel, api, payload);
	            }
	        });
	    }
Layout before each chart render there series, special visual encoding stage

@param {module:echarts/model/Global} ecModel
@private