LineStringの境界に合わせる
最初の座標を LngLatBounds に引き継ぎ、最後の座標を含むようにチェーン拡張することで、LineString の境界を取得します。
<!DOCTYPE html><html><head><meta charset="utf-8" /><title>LineStringの境界に合わせる</title><meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" /><script src="https://api.mapbox.com/mapbox-gl-js/v1.6.1/mapbox-gl.js"></script><link href="https://api.mapbox.com/mapbox-gl-js/v1.6.1/mapbox-gl.css" rel="stylesheet" /><style> body { margin: 0; padding: 0; } #map { position: absolute; top: 0; bottom: 0; width: 100%; }</style></head><body><style>.btn-control {font: bold 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;background-color: #3386c0;color: #fff;position: absolute;top: 20px;left: 50%;z-index: 1;border: none;width: 200px;margin-left: -100px;display: block;cursor: pointer;padding: 10px 20px;border-radius: 3px;} .btn-control:hover {background-color: #4ea0da;}</style><div id="map"></div><button id="zoomto" class="btn-control">Zoom to bounds</button> <script> mapboxgl.accessToken = '<your access token here>';// A GeoJSON object with a LineString route from the White House to Capitol Hillvar geojson = {'type': 'FeatureCollection','features': [{'type': 'Feature','geometry': {'type': 'LineString','properties': {},'coordinates': [[-77.0366048812866, 38.89873175227713],[-77.03364372253417, 38.89876515143842],[-77.03364372253417, 38.89549195896866],[-77.02982425689697, 38.89549195896866],[-77.02400922775269, 38.89387200688839],[-77.01519012451172, 38.891416957534204],[-77.01521158218382, 38.892068305429156],[-77.00813055038452, 38.892051604275686],[-77.00832366943358, 38.89143365883688],[-77.00818419456482, 38.89082405874451],[-77.00815200805664, 38.88989712255097]]}}]}; var map = new mapboxgl.Map({container: 'map',style: 'mapbox://styles/mapbox/light-v10',center: [-77.0214, 38.897],zoom: 12}); map.on('load', function() {map.addLayer({'id': 'LineString','type': 'line','source': {'type': 'geojson','data': geojson},'layout': {'line-join': 'round','line-cap': 'round'},'paint': {'line-color': '#BF93E4','line-width': 5}}); document.getElementById('zoomto').addEventListener('click', function() {// Geographic coordinates of the LineStringvar coordinates = geojson.features[0].geometry.coordinates; // Pass the first coordinates in the LineString to `lngLatBounds` &// wrap each coordinate pair in `extend` to include them in the bounds// result. A variation of this technique could be applied to zooming// to the bounds of multiple Points or Polygon geomteries - it just// requires wrapping all the coordinates with the extend method.var bounds = coordinates.reduce(function(bounds, coord) {return bounds.extend(coord);}, new mapboxgl.LngLatBounds(coordinates[0], coordinates[0])); map.fitBounds(bounds, {padding: 20});});});</script> </body></html>