javascript - 使用 geojson 确定给定地理区域与哪些其他地理区域共享边界

Question

是否可以使用 topojson 或 geojson 来确定给定要素与哪些要素(即国家、州、市)共享边界？对于那些不熟悉 geojson 的人，数据结构如下所示:

{
  "type": "FeatureCollection",
  "features": [
     {
       "type": "Feature",
       "id": "01",
       "properties": { "name": "Alabama" },
       "geometry": {
         "type": "Polygon",
         "coordinates": [[[-87.359296,35.00118],
           [-85.606675,34.984749],[-85.431413,34.124869],
           [-85.184951,32.859696],[-85.069935,32.580372],
           [-84.960397,32.421541],[-85.004212,32.322956],
           [-84.889196,32.262709],[-85.058981,32.13674] …
          ]]
      }
    },
    {
         "type": "Feature",
         "id": "02",
         "properties": { "name": "Alaska" },
         "geometry": {
           "type": "MultiPolygon",
           "coordinates": [[[[-131.602021,55.117982],
             [-131.569159,55.28229],[-131.355558,55.183705],
             [-131.38842,55.01392],[-131.645836,55.035827],
             [-131.602021,55.117982]]],[[[-131.832052,55.42469],
             [-131.645836,55.304197],[-131.749898,55.128935],
             [-131.832052,55.189182], …
            ]]]
          }
      }
// ... more features ...
}

Answer 1

这里的问题与格式无关，但 TopoJSON 使这变得非常简单 - 实际上有一个库方法 topojson.neighbors(objects) ，它应该提供您所需要的:

Returns an array representing the set of neighboring objects for each object in the specified objects array. The returned array has the same number of elements as the input array; each element i in the returned array is the array of indexes for neighbors of object i in the input array. For example, if the specified objects array contains the features foo and bar, and these features are neighbors, the returned array will be [​1, [0]​], indicating that foo is a neighbor of bar and vice versa.