zoom：当前视角的缩放比例。
找了半天，原来是这个属性。

series: [
{
                            type: "map",
                            map: "china",
                            geoIndex: 1,
                            aspectScale: 0.75, //长宽比
                            showLegendSymbol: true, // 存在legend时显示
                            label: {
                                normal: {
                                    show: false
                                },
                                emphasis: {
                                    show: false,
                                    textStyle: {
                                        color: "#fff"
                                    }
                                }
                            },
                            roam: false,
                            zoom: 1.2, 
                            itemStyle: {
                                normal: {
                                    areaColor: "rgba(255,255,255,0)",
                                    borderColor: "#fff",
                                    borderWidth: 1,
                                    shadowColor: '#4341c9'
                                },
                                emphasis: {
                                    areaColor: "#0f2c70"
                                }
                            },
                            data: [
                                {name:"南海诸岛",     //隐藏海南岛
                                    itemStyle:{
                                        normal:{opacity:0,label:{show:false},borderWidth:"0",borderColor:"#10242b",areaStyle:{color:'#10242b'}},
                                        emphasis:{opacity:0,label:{show:false}}
                                    }
                                }
                            ]
                        },
]

放在series里~