最后我用 JSTS 库( https://www.npmjs.com/package/jsts )做到了。
这很容易:
//pathCoords should be an array of jsts.geom.Coordinate
var pathCoords = [];
var geometryFactory = new jsts.geom.GeometryFactory();
// on what distance new polygon should be built
var distance = (meters * 0.0001) / 111.12;
var shell = geometryFactory.createLineString(pathCoords);
// building a new polygon
var polygon = shell.buffer(distance);
// finally get your new polygon coordinates
var polygonCoords = polygon.getCoordinates();
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