GPX変換

GPX のトラック点 ⇔ GeoJSON LineString（基本変換）。

points: 3

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "pointCount": 3
      },
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [
            139.7671,
            35.6812,
            5
          ],
          [
            139.6917,
            35.6895,
            10
          ],
          [
            139.7454,
            35.6586,
            8
          ]
        ]
      }
    }
  ]
}