SOURCE

G7SMap.init({
    id: 'map',
    key: {
        'bmap': 'ebAmxZxmn8hHBm1anhEcTH8j',
      	'gmap': 'AIzaSyBdZt3pUFIFTWKlHqUA_m6GJo_V--k84KU'
    }
}).then(function (map) {
  	// map即为初始化完成的 G7SMap 地图实例对象
  	
  	if (G7SMap.getVendor() === 'bmap') {
      	G7SMap.loadPlugins(['measureTool'], function () {
            var measureTool = new G7SMap.plugins.MeasureTool();
          	
          	document.querySelector('.ranging').addEventListener('click', function () {
            		measureTool.open();
            });
        });
    } else {
      	alert('MeasureTool插件不支持谷歌地图');
    }
});

<div id="map" class="map"></div>
<div>
  <button class="ranging">测距</button>
</div>

.map {
  max-width: 800px;
  height: 500px;
}
.result {
  color: #f60;
}