function genData(len, offset) { var lngRange = [-10.781327, 131.48]; var latRange = [18.252847, 52.33]; var arr = new Float32Array(len * 2); var off = 0; for (var i = 0; i < len; i++) { var x = +Math.random() * 10; var y = +Math.sin(x) - x * (len % 2 ? 0.1 : -0.1) * Math.random() + (offset || 0) / 10; arr[off++] = x; arr[off++] = y; } return arr; } var data1 = genData(5e5); var data2 = genData(5e5, 10); option = { title: { text: echarts.format.addCommas(data1.length / 2 + data2.length / 2) + ' Points' }, tooltip: {}, toolbox: { left: 'center', feature: { dataZoom: {} } }, legend: { orient: 'vertical', right: 10 }, xAxis: [{ }], yAxis: [{ }], dataZoom: [{ type: 'inside' }, { type: 'slider' }], animation: false, series: [{ name: 'A', type: 'scatter', data: data1, dimensions: ['x', 'y'], symbolSize: 3, itemStyle: { opacity: 0.4 }, large: true }, { name: 'B', type: 'scatter', data: data2, dimensions: ['x', 'y'], symbolSize: 3, itemStyle: { opacity: 0.4 }, large: true }] };